diff --git a/spec/AccountLockoutPolicy.spec.js b/spec/AccountLockoutPolicy.spec.js
index 43212d0e69..4d598417d5 100644
--- a/spec/AccountLockoutPolicy.spec.js
+++ b/spec/AccountLockoutPolicy.spec.js
@@ -3,13 +3,14 @@
 const Config = require('../lib/Config');
 const Definitions = require('../lib/Options/Definitions');
 const request = require('../lib/request');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 const loginWithWrongCredentialsShouldFail = function (username, password) {
   return new Promise((resolve, reject) => {
     Parse.User.logIn(username, password)
       .then(() => reject('login should have failed'))
       .catch(err => {
-        if (err.message === 'Invalid username/password.') {
+        if (err.message === ErrorMessage.invalid('username/password')) {
           resolve();
         } else {
           reject(err);
@@ -24,12 +25,7 @@ const isAccountLockoutError = function (username, password, duration, waitTime)
       Parse.User.logIn(username, password)
         .then(() => reject('login should have failed'))
         .catch(err => {
-          if (
-            err.message ===
-            'Your account is locked due to multiple failed login attempts. Please try again after ' +
-              duration +
-              ' minute(s)'
-          ) {
+          if (err.message === ErrorMessage.accountLocked(duration)) {
             resolve();
           } else {
             reject(err);
diff --git a/spec/AuthenticationAdapters.spec.js b/spec/AuthenticationAdapters.spec.js
index 89eeb51231..d723c3f81c 100644
--- a/spec/AuthenticationAdapters.spec.js
+++ b/spec/AuthenticationAdapters.spec.js
@@ -250,7 +250,7 @@ describe('AuthenticationProviders', function () {
       })
       .then(fail, ({ data }) => {
         expect(data.code).toBe(208);
-        expect(data.error).toBe('this auth is already used');
+        expect(data.error).toBe('This auth is already used.');
         done();
       })
       .catch(done.fail);
diff --git a/spec/EmailVerificationToken.spec.js b/spec/EmailVerificationToken.spec.js
index 50b626de0d..b9c2b964a2 100644
--- a/spec/EmailVerificationToken.spec.js
+++ b/spec/EmailVerificationToken.spec.js
@@ -2,6 +2,7 @@
 
 const Config = require('../lib/Config');
 const request = require('../lib/request');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 describe('Email Verification Token Expiration: ', () => {
   it('show the invalid verification link page, if the user clicks on the verify email link after the email verify token expires', done => {
@@ -848,7 +849,7 @@ describe('Email Verification Token Expiration: ', () => {
           .then(response => {
             expect(response.status).toBe(400);
             expect(response.data.code).toBe(Parse.Error.EMAIL_MISSING);
-            expect(response.data.error).toBe('you must provide an email');
+            expect(response.data.error).toBe(ErrorMessage.required('email'));
             expect(sendVerificationEmailCallCount).toBe(0);
             expect(sendEmailOptions).not.toBeDefined();
             done();
diff --git a/spec/ParseGraphQLServer.spec.js b/spec/ParseGraphQLServer.spec.js
index d204886fe5..94ede6c8ce 100644
--- a/spec/ParseGraphQLServer.spec.js
+++ b/spec/ParseGraphQLServer.spec.js
@@ -4188,7 +4188,7 @@ describe('ParseGraphQLServer', () => {
                 .slice(0, 3)
                 .map(obj =>
                   expectAsync(getObject(obj.className, obj.id)).toBeRejectedWith(
-                    jasmine.stringMatching('Object not found')
+                    jasmine.stringMatching('Object not found.')
                   )
                 )
             );
@@ -4232,7 +4232,7 @@ describe('ParseGraphQLServer', () => {
               getObject(object2.className, object2.id, {
                 'X-Parse-Session-Token': user3.getSessionToken(),
               })
-            ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+            ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
             await Promise.all(
               [object1, object3, object4].map(async obj =>
                 expect(
@@ -4250,7 +4250,7 @@ describe('ParseGraphQLServer', () => {
                   getObject(obj.className, obj.id, {
                     'X-Parse-Session-Token': user4.getSessionToken(),
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'))
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'))
               )
             );
             expect(
@@ -4266,7 +4266,7 @@ describe('ParseGraphQLServer', () => {
                   getObject(obj.className, obj.id, {
                     'X-Parse-Session-Token': user5.getSessionToken(),
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'))
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'))
               )
             );
             expect(
@@ -6036,7 +6036,7 @@ describe('ParseGraphQLServer', () => {
                   updateObject(obj.className, obj.id, {
                     someField: 'changedValue1',
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6122,7 +6122,7 @@ describe('ParseGraphQLServer', () => {
                 { someField: 'changedValue5' },
                 { 'X-Parse-Session-Token': user3.getSessionToken() }
               )
-            ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+            ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
             await object2.fetch({ useMasterKey: true });
             expect(object2.get('someField')).toEqual(originalFieldValue);
             await Promise.all(
@@ -6135,7 +6135,7 @@ describe('ParseGraphQLServer', () => {
                     { someField: 'changedValue6' },
                     { 'X-Parse-Session-Token': user4.getSessionToken() }
                   )
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6162,7 +6162,7 @@ describe('ParseGraphQLServer', () => {
                     { someField: 'changedValue7' },
                     { 'X-Parse-Session-Token': user5.getSessionToken() }
                   )
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6234,7 +6234,7 @@ describe('ParseGraphQLServer', () => {
                   updateObject(obj.className, obj.id, {
                     someField: 'changedValue1',
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6330,7 +6330,7 @@ describe('ParseGraphQLServer', () => {
                 { someField: 'changedValue5' },
                 { 'X-Parse-Session-Token': user3.getSessionToken() }
               )
-            ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+            ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
             await object2.fetch({ useMasterKey: true });
             expect(object2.get('someField')).toEqual(originalFieldValue);
             await Promise.all(
@@ -6343,7 +6343,7 @@ describe('ParseGraphQLServer', () => {
                     { someField: 'changedValue6' },
                     { 'X-Parse-Session-Token': user4.getSessionToken() }
                   )
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6372,7 +6372,7 @@ describe('ParseGraphQLServer', () => {
                     { someField: 'changedValue7' },
                     { 'X-Parse-Session-Token': user5.getSessionToken() }
                   )
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6446,7 +6446,7 @@ describe('ParseGraphQLServer', () => {
             expect(result.data.deleteCustomer.customer.someField2).toEqual('someField2Value1');
 
             await expectAsync(obj.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
           });
 
@@ -6482,7 +6482,7 @@ describe('ParseGraphQLServer', () => {
               objects.slice(0, 3).map(async obj => {
                 const originalFieldValue = obj.get('someField');
                 await expectAsync(deleteObject(obj.className, obj.id)).toBeRejectedWith(
-                  jasmine.stringMatching('Object not found')
+                  jasmine.stringMatching('Object not found.')
                 );
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
@@ -6495,7 +6495,7 @@ describe('ParseGraphQLServer', () => {
                   deleteObject(obj.className, obj.id, {
                     'X-Parse-Session-Token': user4.getSessionToken(),
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6506,7 +6506,7 @@ describe('ParseGraphQLServer', () => {
               ]
             ).toEqual({ objectId: object4.id, __typename: 'PublicClass' });
             await expectAsync(object4.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
             expect(
               (
@@ -6516,7 +6516,7 @@ describe('ParseGraphQLServer', () => {
               ).data.delete[object1.className.charAt(0).toLowerCase() + object1.className.slice(1)]
             ).toEqual({ objectId: object1.id, __typename: 'GraphQLClass' });
             await expectAsync(object1.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
             expect(
               (
@@ -6526,7 +6526,7 @@ describe('ParseGraphQLServer', () => {
               ).data.delete[object2.className.charAt(0).toLowerCase() + object2.className.slice(1)]
             ).toEqual({ objectId: object2.id, __typename: 'GraphQLClass' });
             await expectAsync(object2.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
             expect(
               (
@@ -6536,7 +6536,7 @@ describe('ParseGraphQLServer', () => {
               ).data.delete[object3.className.charAt(0).toLowerCase() + object3.className.slice(1)]
             ).toEqual({ objectId: object3.id, __typename: 'GraphQLClass' });
             await expectAsync(object3.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
           });
 
@@ -6572,7 +6572,7 @@ describe('ParseGraphQLServer', () => {
               objects.slice(0, 3).map(async obj => {
                 const originalFieldValue = obj.get('someField');
                 await expectAsync(deleteObject(obj.className, obj.id)).toBeRejectedWith(
-                  jasmine.stringMatching('Object not found')
+                  jasmine.stringMatching('Object not found.')
                 );
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
@@ -6585,7 +6585,7 @@ describe('ParseGraphQLServer', () => {
                   deleteObject(obj.className, obj.id, {
                     'X-Parse-Session-Token': user4.getSessionToken(),
                   })
-                ).toBeRejectedWith(jasmine.stringMatching('Object not found'));
+                ).toBeRejectedWith(jasmine.stringMatching('Object not found.'));
                 await obj.fetch({ useMasterKey: true });
                 expect(obj.get('someField')).toEqual(originalFieldValue);
               })
@@ -6596,7 +6596,7 @@ describe('ParseGraphQLServer', () => {
               ][object4.className.charAt(0).toLowerCase() + object4.className.slice(1)].objectId
             ).toEqual(object4.id);
             await expectAsync(object4.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
             expect(
               (
@@ -6608,7 +6608,7 @@ describe('ParseGraphQLServer', () => {
               ].objectId
             ).toEqual(object1.id);
             await expectAsync(object1.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
             expect(
               (
@@ -6632,7 +6632,7 @@ describe('ParseGraphQLServer', () => {
               ].objectId
             ).toEqual(object3.id);
             await expectAsync(object3.fetch({ useMasterKey: true })).toBeRejectedWith(
-              jasmine.stringMatching('Object not found')
+              jasmine.stringMatching('Object not found.')
             );
           });
         });
diff --git a/spec/ParseInstallation.spec.js b/spec/ParseInstallation.spec.js
index b11f1337e5..d777bd56b9 100644
--- a/spec/ParseInstallation.spec.js
+++ b/spec/ParseInstallation.spec.js
@@ -1232,7 +1232,9 @@ describe('Installations', () => {
           },
           err => {
             expect(err.code).toBe(136);
-            expect(err.message).toBe('installationId may not be changed in this operation');
+            expect(err.message).toBe(
+              'The field installationId can not be changed in this operation.'
+            );
             done();
           }
         );
diff --git a/spec/ParseQuery.FullTextSearch.spec.js b/spec/ParseQuery.FullTextSearch.spec.js
index e6614e5d81..96cfebc0c1 100644
--- a/spec/ParseQuery.FullTextSearch.spec.js
+++ b/spec/ParseQuery.FullTextSearch.spec.js
@@ -3,6 +3,7 @@
 const Config = require('../lib/Config');
 const Parse = require('parse/node');
 const request = require('../lib/request');
+const { ErrorMessage } = require('../lib/Errors/message');
 let databaseAdapter;
 
 const fullTextHelper = async () => {
@@ -110,7 +111,10 @@ describe('Parse.Query Full Text Search testing', () => {
       }
     };
     await expectAsync(invalidQuery()).toBeRejectedWith(
-      new Parse.Error(Parse.Error.INVALID_JSON, 'bad $text: $search, should be object')
+      new Parse.Error(
+        Parse.Error.INVALID_JSON,
+        ErrorMessage.queryValueTypeInvalid('object', '$text.$search')
+      )
     );
   });
 
@@ -119,7 +123,10 @@ describe('Parse.Query Full Text Search testing', () => {
     const query = new Parse.Query('TestObject');
     query.fullText('subject', 'leche', { language: true });
     await expectAsync(query.find()).toBeRejectedWith(
-      new Parse.Error(Parse.Error.INVALID_JSON, 'bad $text: $language, should be string')
+      new Parse.Error(
+        Parse.Error.INVALID_JSON,
+        ErrorMessage.queryValueTypeInvalid('string', '$text.$language')
+      )
     );
   });
 
@@ -128,7 +135,10 @@ describe('Parse.Query Full Text Search testing', () => {
     const query = new Parse.Query('TestObject');
     query.fullText('subject', 'leche', { caseSensitive: 'string' });
     await expectAsync(query.find()).toBeRejectedWith(
-      new Parse.Error(Parse.Error.INVALID_JSON, 'bad $text: $caseSensitive, should be boolean')
+      new Parse.Error(
+        Parse.Error.INVALID_JSON,
+        ErrorMessage.queryValueTypeInvalid('boolean', '$text.$caseSensitive')
+      )
     );
   });
 
@@ -137,7 +147,10 @@ describe('Parse.Query Full Text Search testing', () => {
     const query = new Parse.Query('TestObject');
     query.fullText('subject', 'leche', { diacriticSensitive: 'string' });
     await expectAsync(query.find()).toBeRejectedWith(
-      new Parse.Error(Parse.Error.INVALID_JSON, 'bad $text: $diacriticSensitive, should be boolean')
+      new Parse.Error(
+        Parse.Error.INVALID_JSON,
+        ErrorMessage.queryValueTypeInvalid('boolean', '$text.$diacriticSensitive')
+      )
     );
   });
 });
diff --git a/spec/ParseQuery.spec.js b/spec/ParseQuery.spec.js
index 6de0957999..d49ce31434 100644
--- a/spec/ParseQuery.spec.js
+++ b/spec/ParseQuery.spec.js
@@ -5,6 +5,7 @@
 'use strict';
 
 const Parse = require('parse/node');
+const { ErrorMessage } = require('../lib/Errors/message');
 const request = require('../lib/request');
 
 const masterKeyHeaders = {
@@ -980,7 +981,7 @@ describe('Parse.Query testing', () => {
       .then(done.fail)
       .catch(response => {
         equal(response.data.code, Parse.Error.INVALID_JSON);
-        equal(response.data.error, 'bad $containedBy: should be an array');
+        equal(response.data.error, ErrorMessage.queryValueTypeInvalid('an array', '$containedBy'));
         done();
       });
   });
@@ -1319,7 +1320,7 @@ describe('Parse.Query testing', () => {
       .then(done.fail)
       .catch(error => {
         equal(error.code, Parse.Error.INVALID_JSON);
-        equal(error.message, 'bad $in value');
+        equal(error.message, ErrorMessage.objectFieldValueInvalid('$in'));
         done();
       });
   });
@@ -1339,7 +1340,7 @@ describe('Parse.Query testing', () => {
       .then(done.fail)
       .catch(error => {
         equal(error.code, Parse.Error.INVALID_JSON);
-        equal(error.message, 'bad $nin value');
+        equal(error.message, ErrorMessage.objectFieldValueInvalid('$nin'));
         done();
       });
   });
diff --git a/spec/ParseServerRESTController.spec.js b/spec/ParseServerRESTController.spec.js
index 1b136808b9..4ca63fe8af 100644
--- a/spec/ParseServerRESTController.spec.js
+++ b/spec/ParseServerRESTController.spec.js
@@ -4,6 +4,7 @@ const ParseServer = require('../lib/ParseServer').default;
 const Parse = require('parse/node').Parse;
 const semver = require('semver');
 const TestUtils = require('../lib/TestUtils');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 let RESTController;
 
@@ -569,7 +570,7 @@ describe('ParseServerRESTController', () => {
       fail('Success callback should not be called when passing an empty username.');
     } catch (err) {
       expect(err.code).toBe(Parse.Error.USERNAME_MISSING);
-      expect(err.message).toBe('bad or missing username');
+      expect(err.message).toBe(ErrorMessage.required('username', ''));
     }
   });
 
@@ -582,7 +583,7 @@ describe('ParseServerRESTController', () => {
       fail('Success callback should not be called when passing an empty password.');
     } catch (err) {
       expect(err.code).toBe(Parse.Error.PASSWORD_MISSING);
-      expect(err.message).toBe('password is required');
+      expect(err.message).toBe(ErrorMessage.required('password', ''));
     }
   });
 
diff --git a/spec/ParseUser.spec.js b/spec/ParseUser.spec.js
index 80f6254be8..faa1446cd4 100644
--- a/spec/ParseUser.spec.js
+++ b/spec/ParseUser.spec.js
@@ -12,6 +12,7 @@ const request = require('../lib/request');
 const passwordCrypto = require('../lib/password');
 const Config = require('../lib/Config');
 const cryptoUtils = require('../lib/cryptoUtils');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 describe('Parse.User testing', () => {
   it('user sign up class method', async done => {
@@ -73,7 +74,9 @@ describe('Parse.User testing', () => {
       .catch(err => {
         expect(err.status).toBe(404);
         expect(err.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       });
@@ -102,7 +105,9 @@ describe('Parse.User testing', () => {
       .catch(err => {
         expect(err.status).toBe(404);
         expect(err.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       });
@@ -231,7 +236,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.message).toBe('Invalid username/password.');
+        expect(err.message).toBe(ErrorMessage.invalid('username/password'));
         expect(err.code).toBe(Parse.Error.OBJECT_NOT_FOUND);
         done();
       });
@@ -1910,7 +1915,7 @@ describe('Parse.User testing', () => {
         },
         err => {
           expect(err.code).toBe(Parse.Error.OBJECT_NOT_FOUND);
-          expect(err.message).toEqual('Invalid username/password.');
+          expect(err.message).toEqual(ErrorMessage.invalid('username/password'));
           done();
         }
       );
@@ -2206,7 +2211,7 @@ describe('Parse.User testing', () => {
       user2.set('username', 'Test1');
       user2.set('password', 'test');
       await expectAsync(user2.signUp()).toBeRejectedWith(
-        new Parse.Error(Parse.Error.USERNAME_TAKEN, 'Account already exists for this username.')
+        new Parse.Error(Parse.Error.USERNAME_TAKEN, ErrorMessage.exists('Account', 'username'))
       );
     });
 
@@ -2220,7 +2225,7 @@ describe('Parse.User testing', () => {
       user2.setUsername('Test1');
       user2.setPassword('test');
       await expectAsync(user2.signUp()).toBeRejectedWith(
-        new Parse.Error(Parse.Error.USERNAME_TAKEN, 'Account already exists for this username.')
+        new Parse.Error(Parse.Error.USERNAME_TAKEN, ErrorMessage.exists('Account', 'username'))
       );
     });
 
@@ -2236,7 +2241,7 @@ describe('Parse.User testing', () => {
       user2.setPassword('test');
       user2.setEmail('Test@Example.Com');
       await expectAsync(user2.signUp()).toBeRejectedWith(
-        new Parse.Error(Parse.Error.EMAIL_TAKEN, 'Account already exists for this email address.')
+        new Parse.Error(Parse.Error.EMAIL_TAKEN, ErrorMessage.exists('Account', 'email address'))
       );
     });
 
@@ -2255,7 +2260,7 @@ describe('Parse.User testing', () => {
 
       user2.setEmail('Test@Example.Com');
       await expectAsync(user2.save()).toBeRejectedWith(
-        new Parse.Error(Parse.Error.EMAIL_TAKEN, 'Account already exists for this email address.')
+        new Parse.Error(Parse.Error.EMAIL_TAKEN, ErrorMessage.exists('Account', 'email address'))
       );
     });
 
@@ -2505,7 +2510,7 @@ describe('Parse.User testing', () => {
               body: JSON.stringify({ foo: 'bar' }),
             }).then(fail, response => {
               const b = response.data;
-              expect(b.error).toBe('Session token required.');
+              expect(b.error).toBe(ErrorMessage.required('Session Token', ''));
               done();
             });
           });
@@ -3022,7 +3027,7 @@ describe('Parse.User testing', () => {
         expect(emailCalled).toBeTruthy();
         expect(emailOptions).toBeDefined();
         expect(err.status).toBe(400);
-        expect(err.text).toMatch('{"code":125,"error":"you must provide a valid email string"}');
+        expect(err.text).toMatch('{"code":125,"error":"' + ErrorMessage.invalid('email') + '"}');
         done();
       });
   });
@@ -3718,7 +3723,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.data.error).toEqual('Invalid username/password.');
+        expect(err.data.error).toEqual(ErrorMessage.invalid('username/password'));
         done();
       });
   });
@@ -3743,7 +3748,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.data.error).toEqual('Invalid username/password.');
+        expect(err.data.error).toEqual(ErrorMessage.invalid('username/password'));
         done();
       });
   });
@@ -3768,7 +3773,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.data.error).toEqual('username/email is required.');
+        expect(err.data.error).toEqual(ErrorMessage.required('username/email', ''));
         done();
       });
   });
@@ -3834,7 +3839,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.message).toEqual('Invalid username/password.');
+        expect(err.message).toEqual(ErrorMessage.invalid('username/password'));
         done();
       });
   });
@@ -3859,7 +3864,7 @@ describe('Parse.User testing', () => {
       })
       .then(done.fail)
       .catch(err => {
-        expect(err.data.error).toEqual('password is required.');
+        expect(err.data.error).toEqual(ErrorMessage.required('password', ''));
         done();
       });
   });
@@ -4162,7 +4167,7 @@ describe('login as other user', () => {
       done();
     } catch (err) {
       expect(err.data.code).toBe(Parse.Error.OBJECT_NOT_FOUND);
-      expect(err.data.error).toBe('user not found');
+      expect(err.data.error).toBe(ErrorMessage.notFound('User'));
     }
 
     const sessionsQuery = new Parse.Query(Parse.Session);
@@ -4227,7 +4232,7 @@ describe('login as other user', () => {
       done();
     } catch (err) {
       expect(err.data.code).toBe(Parse.Error.OPERATION_FORBIDDEN);
-      expect(err.data.error).toBe('master key is required');
+      expect(err.data.error).toBe(ErrorMessage.required('Master Key', ''));
     }
 
     const sessionsQuery = new Parse.Query(Parse.Session);
diff --git a/spec/RegexVulnerabilities.spec.js b/spec/RegexVulnerabilities.spec.js
index 62af4f04e2..c85e061a1e 100644
--- a/spec/RegexVulnerabilities.spec.js
+++ b/spec/RegexVulnerabilities.spec.js
@@ -1,3 +1,4 @@
+const { ErrorMessage } = require('../lib/Errors/message');
 const request = require('../lib/request');
 
 const serverURL = 'http://localhost:8378/1';
@@ -148,7 +149,7 @@ describe('Regex Vulnerabilities', function () {
         fail('should not work');
       } catch (e) {
         expect(e.code).toEqual(Parse.Error.OBJECT_NOT_FOUND);
-        expect(e.message).toEqual('Invalid username/password.');
+        expect(e.message).toEqual(ErrorMessage.invalid('username/password'));
       }
     });
 
diff --git a/spec/RestQuery.spec.js b/spec/RestQuery.spec.js
index c8e3adb49d..181fbf06b0 100644
--- a/spec/RestQuery.spec.js
+++ b/spec/RestQuery.spec.js
@@ -7,6 +7,7 @@ const RestQuery = require('../lib/RestQuery');
 const request = require('../lib/request');
 
 const querystring = require('querystring');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 let config;
 let database;
@@ -165,7 +166,7 @@ describe('rest query', () => {
       err => {
         expect(err.code).toEqual(Parse.Error.OPERATION_FORBIDDEN);
         expect(err.message).toEqual(
-          'This user is not allowed to access ' + 'non-existent class: ClientClassCreation'
+          ErrorMessage.unauthorizedAccess('class', 'ClientClassCreation')
         );
         done();
       }
diff --git a/spec/ValidationAndPasswordsReset.spec.js b/spec/ValidationAndPasswordsReset.spec.js
index d7cc72c7b0..8071d43477 100644
--- a/spec/ValidationAndPasswordsReset.spec.js
+++ b/spec/ValidationAndPasswordsReset.spec.js
@@ -3,6 +3,7 @@
 const MockEmailAdapterWithOptions = require('./support/MockEmailAdapterWithOptions');
 const request = require('../lib/request');
 const Config = require('../lib/Config');
+const { ErrorMessage } = require('../lib/Errors/message.js');
 
 describe('Custom Pages, Email Verification, Password Reset', () => {
   it('should set the custom pages', done => {
@@ -231,7 +232,7 @@ describe('Custom Pages, Email Verification, Password Reset', () => {
               done();
             },
             error => {
-              expect(error.message).toEqual('User email is not verified.');
+              expect(error.message).toEqual(ErrorMessage.unverified('User email'));
               done();
             }
           );
@@ -369,9 +370,7 @@ describe('Custom Pages, Email Verification, Password Reset', () => {
               done();
             },
             error => {
-              expect(error.message).toEqual(
-                'An appName, publicServerURL, and emailAdapter are required for password reset and email verification functionality.'
-              );
+              expect(error.message).toEqual(ErrorMessage.fieldMissingForVerificationFunc());
               done();
             }
           );
@@ -405,9 +404,7 @@ describe('Custom Pages, Email Verification, Password Reset', () => {
               done();
             },
             error => {
-              expect(error.message).toEqual(
-                'An appName, publicServerURL, and emailAdapter are required for password reset and email verification functionality.'
-              );
+              expect(error.message).toEqual(ErrorMessage.fieldMissingForVerificationFunc());
               done();
             }
           );
@@ -438,9 +435,7 @@ describe('Custom Pages, Email Verification, Password Reset', () => {
               done();
             },
             error => {
-              expect(error.message).toEqual(
-                'An appName, publicServerURL, and emailAdapter are required for password reset and email verification functionality.'
-              );
+              expect(error.message).toEqual(ErrorMessage.fieldMissingForVerificationFunc());
               done();
             }
           );
diff --git a/spec/VerifyUserPassword.spec.js b/spec/VerifyUserPassword.spec.js
index 6734dcdb71..2dedadf821 100644
--- a/spec/VerifyUserPassword.spec.js
+++ b/spec/VerifyUserPassword.spec.js
@@ -1,5 +1,6 @@
 'use strict';
 
+const { ErrorMessage } = require('../lib/Errors/message');
 const request = require('../lib/request');
 const MockEmailAdapterWithOptions = require('./support/MockEmailAdapterWithOptions');
 
@@ -23,12 +24,7 @@ const isAccountLockoutError = function (username, password, duration, waitTime)
       Parse.User.logIn(username, password)
         .then(() => reject('login should have failed'))
         .catch(err => {
-          if (
-            err.message ===
-            'Your account is locked due to multiple failed login attempts. Please try again after ' +
-              duration +
-              ' minute(s)'
-          ) {
+          if (err.message === ErrorMessage.accountLocked(duration)) {
             resolve();
           } else {
             reject(err);
@@ -80,7 +76,9 @@ describe('Verify User Password', () => {
       .catch(err => {
         expect(err.status).toBe(404);
         expect(err.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       });
@@ -112,7 +110,9 @@ describe('Verify User Password', () => {
       })
       .catch(err => {
         expect(err.status).toBe(400);
-        expect(err.text).toMatch('{"code":200,"error":"username/email is required."}');
+        expect(err.text).toMatch(
+          '{"code":200,"error":"' + ErrorMessage.required('username/email', '') + '"}'
+        );
         done();
       });
   });
@@ -143,7 +143,9 @@ describe('Verify User Password', () => {
       })
       .catch(err => {
         expect(err.status).toBe(400);
-        expect(err.text).toMatch('{"code":200,"error":"username/email is required."}');
+        expect(err.text).toMatch(
+          '{"code":200,"error":"' + ErrorMessage.required('username/email', '') + '"}'
+        );
         done();
       });
   });
@@ -160,7 +162,9 @@ describe('Verify User Password', () => {
       })
       .then(res => {
         expect(res.status).toBe(400);
-        expect(res.text).toMatch('{"code":200,"error":"username/email is required."}');
+        expect(res.text).toMatch(
+          '{"code":200,"error":"' + ErrorMessage.required('username/email', '') + '"}'
+        );
         done();
       })
       .catch(err => {
@@ -181,7 +185,9 @@ describe('Verify User Password', () => {
       })
       .then(res => {
         expect(res.status).toBe(400);
-        expect(res.text).toMatch('{"code":200,"error":"username/email is required."}');
+        expect(res.text).toMatch(
+          '{"code":200,"error":"' + ErrorMessage.required('username/email', '') + '"}'
+        );
         done();
       })
       .catch(err => {
@@ -202,7 +208,9 @@ describe('Verify User Password', () => {
       })
       .then(res => {
         expect(res.status).toBe(400);
-        expect(res.text).toMatch('{"code":201,"error":"password is required."}');
+        expect(res.text).toMatch(
+          '{"code":201,"error":"' + ErrorMessage.required('password', '') + '"}'
+        );
         done();
       })
       .catch(err => {
@@ -224,7 +232,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -247,7 +257,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -270,7 +282,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -293,7 +307,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -316,7 +332,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -330,7 +348,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
@@ -344,7 +364,9 @@ describe('Verify User Password', () => {
       .then(res => {
         expect(res.status).toBe(404);
         expect(res.text).toMatch(
-          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"Invalid username/password."}`
+          `{"code":${Parse.Error.OBJECT_NOT_FOUND},"error":"${ErrorMessage.invalid(
+            'username/password'
+          )}"}`
         );
         done();
       })
diff --git a/spec/rest.spec.js b/spec/rest.spec.js
index db3082ec74..cdf6e53ac8 100644
--- a/spec/rest.spec.js
+++ b/spec/rest.spec.js
@@ -6,6 +6,7 @@ const Parse = require('parse/node').Parse;
 const rest = require('../lib/rest');
 const RestWrite = require('../lib/RestWrite');
 const request = require('../lib/request');
+const { ErrorMessage } = require('../lib/Errors/message');
 
 let config;
 let database;
@@ -77,7 +78,7 @@ describe('rest create', () => {
       objectId: '',
     };
 
-    const err = 'objectId must not be empty, null or undefined';
+    const err = ErrorMessage.noEmpty('ObjectId');
 
     expect(() => rest.create(config, auth.nobody(config), 'MyClass', objIdEmpty)).toThrowError(err);
 
@@ -214,7 +215,7 @@ describe('rest create', () => {
       err => {
         expect(err.code).toEqual(Parse.Error.OPERATION_FORBIDDEN);
         expect(err.message).toEqual(
-          'This user is not allowed to access ' + 'non-existent class: ClientClassCreation'
+          ErrorMessage.unauthorizedAccess('class', 'ClientClassCreation')
         );
         done();
       }
@@ -504,7 +505,7 @@ describe('rest create', () => {
     }).then(fail, response => {
       const b = response.data;
       expect(b.code).toEqual(105);
-      expect(b.error).toEqual('objectId is an invalid field name.');
+      expect(b.error).toEqual(ErrorMessage.invalid('objectId'));
       done();
     });
   });
@@ -526,7 +527,7 @@ describe('rest create', () => {
     }).then(fail, response => {
       const b = response.data;
       expect(b.code).toEqual(105);
-      expect(b.error).toEqual('id is an invalid field name.');
+      expect(b.error).toEqual(ErrorMessage.invalid('id'));
       done();
     });
   });
@@ -866,7 +867,7 @@ describe('read-only masterKey', () => {
     }).toThrow(
       new Parse.Error(
         Parse.Error.OPERATION_FORBIDDEN,
-        'Cannot perform a write operation when using readOnlyMasterKey'
+        'Cannot perform a write operation when using readOnlyMasterKey.'
       )
     );
   });
diff --git a/spec/schemas.spec.js b/spec/schemas.spec.js
index 9557dd7924..2156c69bf5 100644
--- a/spec/schemas.spec.js
+++ b/spec/schemas.spec.js
@@ -5,6 +5,7 @@ const dd = require('deep-diff');
 const Config = require('../lib/Config');
 const request = require('../lib/request');
 const TestUtils = require('../lib/TestUtils');
+const { ErrorMessage } = require('../lib/Errors/message');
 const SchemaController = require('../lib/Controllers/SchemaController').SchemaController;
 
 let config;
@@ -1119,7 +1120,7 @@ describe('schemas', () => {
           fail('Should fail');
         } catch (e) {
           expect(e.code).toEqual(142);
-          expect(e.message).toEqual('newRequiredField is required');
+          expect(e.message).toEqual(ErrorMessage.required('newRequiredField', undefined, true));
         }
         obj.set('newRequiredField', 'some value');
         await obj.save();
@@ -1134,7 +1135,7 @@ describe('schemas', () => {
           fail('Should fail');
         } catch (e) {
           expect(e.code).toEqual(142);
-          expect(e.message).toEqual('newRequiredField is required');
+          expect(e.message).toEqual(ErrorMessage.required('newRequiredField', undefined, true));
         }
         obj.unset('newRequiredField');
         try {
@@ -1142,7 +1143,7 @@ describe('schemas', () => {
           fail('Should fail');
         } catch (e) {
           expect(e.code).toEqual(142);
-          expect(e.message).toEqual('newRequiredField is required');
+          expect(e.message).toEqual(ErrorMessage.required('newRequiredField', undefined, true));
         }
         obj.set('newRequiredField', 'some value2');
         await obj.save();
@@ -1157,7 +1158,9 @@ describe('schemas', () => {
           fail('Should fail');
         } catch (e) {
           expect(e.code).toEqual(142);
-          expect(e.message).toEqual('newRequiredFieldWithDefaultValue is required');
+          expect(e.message).toEqual(
+            ErrorMessage.required('newRequiredFieldWithDefaultValue', undefined, true)
+          );
         }
         obj.set('newRequiredFieldWithDefaultValue', '');
         try {
@@ -1165,7 +1168,9 @@ describe('schemas', () => {
           fail('Should fail');
         } catch (e) {
           expect(e.code).toEqual(142);
-          expect(e.message).toEqual('newRequiredFieldWithDefaultValue is required');
+          expect(e.message).toEqual(
+            ErrorMessage.required('newRequiredFieldWithDefaultValue', undefined, true)
+          );
         }
         obj.set('newRequiredFieldWithDefaultValue', 'some value2');
         obj.set('newNotRequiredField', '');
@@ -1276,7 +1281,7 @@ describe('schemas', () => {
       await obj.save();
       fail('should fail');
     } catch (e) {
-      expect(e.message).toEqual('foo2 is required');
+      expect(e.message).toEqual(ErrorMessage.required('foo2', undefined, true));
     }
 
     Parse.Cloud.beforeSave('NewClassForBeforeSaveTest', req => {
@@ -1295,7 +1300,7 @@ describe('schemas', () => {
       await obj.save();
       fail('should fail');
     } catch (e) {
-      expect(e.message).toEqual('foo2 is required');
+      expect(e.message).toEqual(ErrorMessage.required('foo2', undefined, true));
     }
   });
 
diff --git a/src/AccountLockout.js b/src/AccountLockout.js
index 13d655e6b7..84fa004342 100644
--- a/src/AccountLockout.js
+++ b/src/AccountLockout.js
@@ -1,5 +1,6 @@
 // This class handles the Account Lockout Policy settings.
 import Parse from 'parse/node';
+import { ErrorMessage } from '../lib/Errors/message';
 
 export class AccountLockout {
   constructor(user, config) {
@@ -118,9 +119,7 @@ export class AccountLockout {
       if (Array.isArray(users) && users.length > 0) {
         throw new Parse.Error(
           Parse.Error.OBJECT_NOT_FOUND,
-          'Your account is locked due to multiple failed login attempts. Please try again after ' +
-            this._config.accountLockout.duration +
-            ' minute(s)'
+          ErrorMessage.accountLocked(this._config.accountLockout.duration)
         );
       }
     });
diff --git a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
index c1fe63ba9b..9291851085 100644
--- a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
+++ b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
@@ -18,6 +18,7 @@ import Parse from 'parse/node';
 import _ from 'lodash';
 import defaults from '../../../defaults';
 import logger from '../../../logger';
+import { ErrorMessage } from '../../../Errors/message';
 
 // @flow-disable-next
 const mongodb = require('mongodb');
@@ -482,10 +483,7 @@ export class MongoStorageAdapter implements StorageAdapter {
       .catch(error => {
         if (error.code === 11000) {
           // Duplicate value
-          const err = new Parse.Error(
-            Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
-          );
+          const err = new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
           err.underlyingError = error;
           if (error.message) {
             const matches = error.message.match(/index:[\sa-zA-Z0-9_\-\.]+\$?([a-zA-Z_-]+)_1/);
@@ -519,12 +517,15 @@ export class MongoStorageAdapter implements StorageAdapter {
       .then(
         ({ result }) => {
           if (result.n === 0) {
-            throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Object not found.');
+            throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, ErrorMessage.notFound('Object'));
           }
           return Promise.resolve();
         },
         () => {
-          throw new Parse.Error(Parse.Error.INTERNAL_SERVER_ERROR, 'Database adapter error');
+          throw new Parse.Error(
+            Parse.Error.INTERNAL_SERVER_ERROR,
+            ErrorMessage.databaseAdapterError()
+          );
         }
       );
   }
@@ -567,10 +568,7 @@ export class MongoStorageAdapter implements StorageAdapter {
       .then(result => mongoObjectToParseObject(className, result.value, schema))
       .catch(error => {
         if (error.code === 11000) {
-          throw new Parse.Error(
-            Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
-          );
+          throw new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
         }
         throw error;
       })
@@ -708,10 +706,7 @@ export class MongoStorageAdapter implements StorageAdapter {
       .then(collection => collection._ensureSparseUniqueIndexInBackground(indexCreationRequest))
       .catch(error => {
         if (error.code === 11000) {
-          throw new Parse.Error(
-            Parse.Error.DUPLICATE_VALUE,
-            'Tried to ensure field uniqueness for a class that already has duplicates.'
-          );
+          throw new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
         }
         throw error;
       })
diff --git a/src/Adapters/Storage/Mongo/MongoTransform.js b/src/Adapters/Storage/Mongo/MongoTransform.js
index 91ad23fa4a..00c7fd4bf1 100644
--- a/src/Adapters/Storage/Mongo/MongoTransform.js
+++ b/src/Adapters/Storage/Mongo/MongoTransform.js
@@ -1,5 +1,6 @@
 import log from '../../../logger';
 import _ from 'lodash';
+import { ErrorMessage } from '../../../Errors/message';
 var mongodb = require('mongodb');
 var Parse = require('parse/node').Parse;
 const Utils = require('../../../Utils');
@@ -708,7 +709,10 @@ function transformConstraint(constraint, field, count = false) {
       case '$nin': {
         const arr = constraint[key];
         if (!(arr instanceof Array)) {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, 'bad ' + key + ' value');
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.objectFieldValueInvalid(key)
+          );
         }
         answer[key] = _.flatMap(arr, value => {
           return (atom => {
@@ -724,7 +728,10 @@ function transformConstraint(constraint, field, count = false) {
       case '$all': {
         const arr = constraint[key];
         if (!(arr instanceof Array)) {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, 'bad ' + key + ' value');
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.objectFieldValueInvalid(key)
+          );
         }
         answer[key] = arr.map(transformInteriorAtom);
 
@@ -749,7 +756,10 @@ function transformConstraint(constraint, field, count = false) {
       case '$containedBy': {
         const arr = constraint[key];
         if (!(arr instanceof Array)) {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $containedBy: should be an array`);
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.queryValueTypeInvalid('an array', '$containedBy')
+          );
         }
         answer.$elemMatch = {
           $nin: arr.map(transformer),
@@ -763,24 +773,33 @@ function transformConstraint(constraint, field, count = false) {
       case '$text': {
         const search = constraint[key].$search;
         if (typeof search !== 'object') {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $search, should be object`);
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.queryValueTypeInvalid('object', '$text.$search')
+          );
         }
         if (!search.$term || typeof search.$term !== 'string') {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $term, should be string`);
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.queryValueTypeInvalid('string', '$text.$term')
+          );
         } else {
           answer[key] = {
             $search: search.$term,
           };
         }
         if (search.$language && typeof search.$language !== 'string') {
-          throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $language, should be string`);
+          throw new Parse.Error(
+            Parse.Error.INVALID_JSON,
+            ErrorMessage.queryValueTypeInvalid('string', '$text.$language')
+          );
         } else if (search.$language) {
           answer[key].$language = search.$language;
         }
         if (search.$caseSensitive && typeof search.$caseSensitive !== 'boolean') {
           throw new Parse.Error(
             Parse.Error.INVALID_JSON,
-            `bad $text: $caseSensitive, should be boolean`
+            ErrorMessage.queryValueTypeInvalid('boolean', '$text.$caseSensitive')
           );
         } else if (search.$caseSensitive) {
           answer[key].$caseSensitive = search.$caseSensitive;
@@ -788,7 +807,7 @@ function transformConstraint(constraint, field, count = false) {
         if (search.$diacriticSensitive && typeof search.$diacriticSensitive !== 'boolean') {
           throw new Parse.Error(
             Parse.Error.INVALID_JSON,
-            `bad $text: $diacriticSensitive, should be boolean`
+            ErrorMessage.queryValueTypeInvalid('boolean', '$text.$diacriticSensitive')
           );
         } else if (search.$diacriticSensitive) {
           answer[key].$diacriticSensitive = search.$diacriticSensitive;
@@ -878,7 +897,10 @@ function transformConstraint(constraint, field, count = false) {
               return point;
             }
             if (!GeoPointCoder.isValidJSON(point)) {
-              throw new Parse.Error(Parse.Error.INVALID_JSON, 'bad $geoWithin value');
+              throw new Parse.Error(
+                Parse.Error.INVALID_JSON,
+                ErrorMessage.objectFieldValueInvalid('$geoWithin')
+              );
             } else {
               Parse.GeoPoint._validate(point.latitude, point.longitude);
             }
diff --git a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
index 7477270a3d..8c9d094141 100644
--- a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
+++ b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
@@ -7,6 +7,7 @@ import _ from 'lodash';
 // @flow-disable-next
 import { v4 as uuidv4 } from 'uuid';
 import sql from './sql';
+import { ErrorMessage } from '../../../Errors/message';
 import { StorageAdapter } from '../StorageAdapter';
 import type { SchemaType, QueryType, QueryOptions } from '../StorageAdapter';
 const Utils = require('../../../Utils');
@@ -226,10 +227,7 @@ const validateKeys = object => {
       }
 
       if (key.includes('$') || key.includes('.')) {
-        throw new Parse.Error(
-          Parse.Error.INVALID_NESTED_KEY,
-          "Nested keys should not contain the '$' or '.' characters"
-        );
+        throw new Parse.Error(Parse.Error.INVALID_NESTED_KEY, ErrorMessage.invalidNestedKey());
       }
     }
   }
@@ -489,9 +487,9 @@ const buildWhereClause = ({ schema, query, index, caseInsensitive }): WhereClaus
         );
       }
     } else if (typeof fieldValue.$in !== 'undefined') {
-      throw new Parse.Error(Parse.Error.INVALID_JSON, 'bad $in value');
+      throw new Parse.Error(Parse.Error.INVALID_JSON, ErrorMessage.objectFieldValueInvalid('$in'));
     } else if (typeof fieldValue.$nin !== 'undefined') {
-      throw new Parse.Error(Parse.Error.INVALID_JSON, 'bad $nin value');
+      throw new Parse.Error(Parse.Error.INVALID_JSON, ErrorMessage.objectFieldValueInvalid('$nin'));
     }
 
     if (Array.isArray(fieldValue.$all) && isArrayField) {
@@ -499,7 +497,7 @@ const buildWhereClause = ({ schema, query, index, caseInsensitive }): WhereClaus
         if (!isAllValuesRegexOrNone(fieldValue.$all)) {
           throw new Parse.Error(
             Parse.Error.INVALID_JSON,
-            'All $all values must be of regex type or none: ' + fieldValue.$all
+            ErrorMessage.queryValueTypeInvalid(`regex type or none: ${fieldValue.$all}`, '$all')
           );
         }
 
@@ -539,7 +537,10 @@ const buildWhereClause = ({ schema, query, index, caseInsensitive }): WhereClaus
     if (fieldValue.$containedBy) {
       const arr = fieldValue.$containedBy;
       if (!(arr instanceof Array)) {
-        throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $containedBy: should be an array`);
+        throw new Parse.Error(
+          Parse.Error.INVALID_JSON,
+          ErrorMessage.queryValueTypeInvalid('an array', '$containedBy')
+        );
       }
 
       patterns.push(`$${index}:name <@ $${index + 1}::jsonb`);
@@ -551,36 +552,48 @@ const buildWhereClause = ({ schema, query, index, caseInsensitive }): WhereClaus
       const search = fieldValue.$text.$search;
       let language = 'english';
       if (typeof search !== 'object') {
-        throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $search, should be object`);
+        throw new Parse.Error(
+          Parse.Error.INVALID_JSON,
+          ErrorMessage.queryValueTypeInvalid('object', '$text.$search')
+        );
       }
       if (!search.$term || typeof search.$term !== 'string') {
-        throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $term, should be string`);
+        throw new Parse.Error(
+          Parse.Error.INVALID_JSON,
+          ErrorMessage.queryValueTypeInvalid('string', '$text.$term')
+        );
       }
       if (search.$language && typeof search.$language !== 'string') {
-        throw new Parse.Error(Parse.Error.INVALID_JSON, `bad $text: $language, should be string`);
+        throw new Parse.Error(
+          Parse.Error.INVALID_JSON,
+          ErrorMessage.queryValueTypeInvalid('string', '$text.$language')
+        );
       } else if (search.$language) {
         language = search.$language;
       }
       if (search.$caseSensitive && typeof search.$caseSensitive !== 'boolean') {
         throw new Parse.Error(
           Parse.Error.INVALID_JSON,
-          `bad $text: $caseSensitive, should be boolean`
+          ErrorMessage.queryValueTypeInvalid('boolean', '$text.$caseSensitive')
         );
       } else if (search.$caseSensitive) {
         throw new Parse.Error(
           Parse.Error.INVALID_JSON,
-          `bad $text: $caseSensitive not supported, please use $regex or create a separate lower case column.`
+          ErrorMessage.queryValueTypeInvalid('boolean', '$text.$caseSensitive')
         );
       }
       if (search.$diacriticSensitive && typeof search.$diacriticSensitive !== 'boolean') {
         throw new Parse.Error(
           Parse.Error.INVALID_JSON,
-          `bad $text: $diacriticSensitive, should be boolean`
+          ErrorMessage.queryValueTypeInvalid('boolean', '$text.$diacriticSensitive')
         );
       } else if (search.$diacriticSensitive === false) {
         throw new Parse.Error(
           Parse.Error.INVALID_JSON,
-          `bad $text: $diacriticSensitive - false not supported, install Postgres Unaccent Extension`
+          ErrorMessage.databasePostgresExtensionRequired(
+            '$text: $diacriticSensitive - false',
+            'Postgres Unaccent'
+          )
         );
       }
       patterns.push(
@@ -625,7 +638,10 @@ const buildWhereClause = ({ schema, query, index, caseInsensitive }): WhereClaus
       if (!(centerSphere instanceof Array) || centerSphere.length < 2) {
         throw new Parse.Error(
           Parse.Error.INVALID_JSON,
-          'bad $geoWithin value; $centerSphere should be an array of Parse.GeoPoint and distance'
+          ErrorMessage.queryValueTypeInvalid(
+            'an array of Parse.GeoPoint and distance',
+            '$geoWithin value; $centerSphere'
+          )
         );
       }
       // Get point, convert to geo point if necessary and validate
@@ -1004,7 +1020,10 @@ export class PostgresStorageAdapter implements StorageAdapter {
       })
       .catch(err => {
         if (err.code === PostgresUniqueIndexViolationError && err.detail.includes(className)) {
-          throw new Parse.Error(Parse.Error.DUPLICATE_VALUE, `Class ${className} already exists.`);
+          throw new Parse.Error(
+            Parse.Error.DUPLICATE_VALUE,
+            ErrorMessage.exists('Class', className)
+          );
         }
         throw err;
       });
@@ -1419,10 +1438,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
       .then(() => ({ ops: [object] }))
       .catch(error => {
         if (error.code === PostgresUniqueIndexViolationError) {
-          const err = new Parse.Error(
-            Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
-          );
+          const err = new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
           err.underlyingError = error;
           if (error.constraint) {
             const matches = error.constraint.match(/unique_([a-zA-Z]+)/);
@@ -1467,7 +1483,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
       .one(qs, values, a => +a.count)
       .then(count => {
         if (count === 0) {
-          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Object not found.');
+          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, ErrorMessage.notFound('Object'));
         } else {
           return count;
         }
@@ -1984,10 +2000,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
         error.message.includes(constraintName)
       ) {
         // Cast the error into the proper parse error
-        throw new Parse.Error(
-          Parse.Error.DUPLICATE_VALUE,
-          'A duplicate value for a field with unique values was provided'
-        );
+        throw new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
       } else {
         throw error;
       }
@@ -2458,7 +2471,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
           // Cast the error into the proper parse error
           throw new Parse.Error(
             Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
+            ErrorMessage.duplicateValue()
           );
         } else {
           throw error;
@@ -2494,7 +2507,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
 
 function convertPolygonToSQL(polygon) {
   if (polygon.length < 3) {
-    throw new Parse.Error(Parse.Error.INVALID_JSON, `Polygon must have at least 3 values`);
+    throw new Parse.Error(Parse.Error.INVALID_JSON, ErrorMessage.invalidPolygonValues());
   }
   if (
     polygon[0][0] !== polygon[polygon.length - 1][0] ||
@@ -2514,10 +2527,7 @@ function convertPolygonToSQL(polygon) {
     return foundIndex === index;
   });
   if (unique.length < 3) {
-    throw new Parse.Error(
-      Parse.Error.INTERNAL_SERVER_ERROR,
-      'GeoJSON: Loop must have at least 3 different vertices'
-    );
+    throw new Parse.Error(Parse.Error.INTERNAL_SERVER_ERROR, ErrorMessage.geoJsonInvalidVertices());
   }
   const points = polygon
     .map(point => {
diff --git a/src/Errors/message.js b/src/Errors/message.js
new file mode 100644
index 0000000000..d58cea24fa
--- /dev/null
+++ b/src/Errors/message.js
@@ -0,0 +1,41 @@
+export const ErrorMessage = {
+  masterKeyReadOnly: () => 'Cannot perform a write operation when using readOnlyMasterKey.',
+  noEmpty: (field, isField = true) =>
+    `${isField === true ? 'The field ' : ''}${field} must not be empty, null or undefined.`,
+  invalid: (field, isField = true) => `${isField === true ? 'The field' : ''} ${field} is invalid.`,
+  unauthorizedAccess: (type, value) => `This user is not allowed to access ${type}: ${value}`,
+  notFound: type => `${type} not found.`,
+  exists: (type, key) => `${type} ${key} already exists`,
+  required: (field, op = 'to save/update the object', isField = false) =>
+    `A value for ${isField === true ? 'field ' : ''}${field} is required${op ? ' ' : ''}${op}.`,
+  verified: type => `${type} is already verified.`,
+  unverified: type => `${type} is not verified.`,
+  noUpdate: (type, key) => `Can not update ${type} ${key}`,
+  unsupportedService: () => 'This authentication method is unsupported.',
+  accountLinked: () => 'This auth is already used.',
+  accountLocked: duration =>
+    `Your account is locked due to multiple failed login attempts. Please try again after ${duration} minute(s).`,
+  clientEmailVerification: () => "Clients aren't allowed to manually update email verification.",
+  passwordPolicy: () => 'Password does not meet the Password Policy requirements.',
+  usernameInPassword: () => 'Password cannot contain your username.',
+  passwordMatchesExistingPassword: maxPasswordHistory =>
+    `New password should not be the same as last ${maxPasswordHistory} passwords.`,
+  aclSession: () => 'Cannot set ACL on a Session.',
+  sessionError: () => 'Error creating session.',
+  noOp: field => `The field ${field} can not be changed in this operation.`,
+  reqOp: field => `The field ${field} must be specified in this operation.`,
+  installationIdWithDeviceToken: () =>
+    'Must specify installationId when deviceToken matches multiple Installation objects.',
+  invalidAcl: () => 'Invalid ACL.',
+  duplicateValue: () => 'A duplicate value for a field with unique values was provided.',
+  databaseAdapterError: () => 'Database adapter error.',
+  geoJsonInvalidVertices: () => 'GeoJSON: Loop must have at least 3 different vertices.',
+  invalidPolygonValues: () => 'Polygon must have at least 3 values.',
+  invalidNestedKey: () => "Nested keys should not contain the '$' or '.' characters",
+  objectFieldValueInvalid: type => `Invalid ${type} value provided.`,
+  queryValueTypeInvalid: (type, key) => `Value of '${key}' must be of type ${type}.`,
+  databasePostgresExtensionRequired: (key, extension) =>
+    `Query key ${key} requires Postgres extension ${extension}.`,
+  fieldMissingForVerificationFunc: () =>
+    'An appName, publicServerURL, and emailAdapter are required for password reset and email verification functionality.',
+};
diff --git a/src/GraphQL/loaders/usersMutations.js b/src/GraphQL/loaders/usersMutations.js
index c38905cd90..b630c1aca6 100644
--- a/src/GraphQL/loaders/usersMutations.js
+++ b/src/GraphQL/loaders/usersMutations.js
@@ -7,6 +7,7 @@ import { OBJECT } from './defaultGraphQLTypes';
 import { getUserFromSessionToken } from './usersQueries';
 import { transformTypes } from '../transformers/mutation';
 import Parse from 'parse/node';
+import { ErrorMessage } from '../../Errors/message';
 
 const usersRouter = new UsersRouter();
 
@@ -279,13 +280,13 @@ const load = parseGraphQLSchema => {
     mutateAndGetPayload: async ({ username, password, token }, context) => {
       const { config } = context;
       if (!username) {
-        throw new Parse.Error(Parse.Error.USERNAME_MISSING, 'you must provide a username');
+        throw new Parse.Error(Parse.Error.USERNAME_MISSING, ErrorMessage.required('username', ''));
       }
       if (!password) {
-        throw new Parse.Error(Parse.Error.PASSWORD_MISSING, 'you must provide a password');
+        throw new Parse.Error(Parse.Error.PASSWORD_MISSING, ErrorMessage.required('password', ''));
       }
       if (!token) {
-        throw new Parse.Error(Parse.Error.OTHER_CAUSE, 'you must provide a token');
+        throw new Parse.Error(Parse.Error.OTHER_CAUSE, ErrorMessage.fieldIsRequired('token'));
       }
 
       const userController = config.userController;
diff --git a/src/RestQuery.js b/src/RestQuery.js
index be96683451..cf9ced0ace 100644
--- a/src/RestQuery.js
+++ b/src/RestQuery.js
@@ -6,6 +6,8 @@ var Parse = require('parse/node').Parse;
 const triggers = require('./triggers');
 const { continueWhile } = require('parse/lib/node/promiseUtils');
 const AlwaysSelectedKeys = ['objectId', 'createdAt', 'updatedAt', 'ACL'];
+const { ErrorMessage } = require('./Errors/message');
+
 // restOptions can include:
 //   skip
 //   limit
@@ -335,7 +337,7 @@ RestQuery.prototype.validateClientClassCreation = function () {
         if (hasClass !== true) {
           throw new Parse.Error(
             Parse.Error.OPERATION_FORBIDDEN,
-            'This user is not allowed to access ' + 'non-existent class: ' + this.className
+            ErrorMessage.unauthorizedAccess('class', this.className)
           );
         }
       });
diff --git a/src/RestWrite.js b/src/RestWrite.js
index a651cf9c6c..674b767e5a 100644
--- a/src/RestWrite.js
+++ b/src/RestWrite.js
@@ -14,6 +14,7 @@ var ClientSDK = require('./ClientSDK');
 import RestQuery from './RestQuery';
 import _ from 'lodash';
 import logger from './logger';
+import { ErrorMessage } from './Errors/message';
 
 // query and data are both provided in REST API format. So data
 // types are encoded by plain old objects.
@@ -26,10 +27,7 @@ import logger from './logger';
 // for the _User class.
 function RestWrite(config, auth, className, query, data, originalData, clientSDK, context, action) {
   if (auth.isReadOnly) {
-    throw new Parse.Error(
-      Parse.Error.OPERATION_FORBIDDEN,
-      'Cannot perform a write operation when using readOnlyMasterKey'
-    );
+    throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, ErrorMessage.masterKeyReadOnly());
   }
   this.config = config;
   this.auth = auth;
@@ -46,17 +44,14 @@ function RestWrite(config, auth, className, query, data, originalData, clientSDK
   if (!query) {
     if (this.config.allowCustomObjectId) {
       if (Object.prototype.hasOwnProperty.call(data, 'objectId') && !data.objectId) {
-        throw new Parse.Error(
-          Parse.Error.MISSING_OBJECT_ID,
-          'objectId must not be empty, null or undefined'
-        );
+        throw new Parse.Error(Parse.Error.MISSING_OBJECT_ID, ErrorMessage.noEmpty('ObjectId'));
       }
     } else {
       if (data.objectId) {
-        throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, 'objectId is an invalid field name.');
+        throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, ErrorMessage.invalid('objectId'));
       }
       if (data.id) {
-        throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, 'id is an invalid field name.');
+        throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, ErrorMessage.invalid('id'));
       }
     }
   }
@@ -178,7 +173,7 @@ RestWrite.prototype.validateClientClassCreation = function () {
         if (hasClass !== true) {
           throw new Parse.Error(
             Parse.Error.OPERATION_FORBIDDEN,
-            'This user is not allowed to access ' + 'non-existent class: ' + this.className
+            ErrorMessage.unauthorizedAccess('class', this.className)
           );
         }
       });
@@ -250,7 +245,7 @@ RestWrite.prototype.runBeforeSaveTrigger = function () {
       // In the case that there is no permission for the operation, it throws an error
       return databasePromise.then(result => {
         if (!result || result.length <= 0) {
-          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Object not found.');
+          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, ErrorMessage.notFound('Object'));
         }
       });
     })
@@ -337,7 +332,10 @@ RestWrite.prototype.setRequiredFieldsIfNeeded = function () {
               this.storage.fieldsChangedByTrigger.push(fieldName);
             }
           } else if (schema.fields[fieldName] && schema.fields[fieldName].required === true) {
-            throw new Parse.Error(Parse.Error.VALIDATION_ERROR, `${fieldName} is required`);
+            throw new Parse.Error(
+              Parse.Error.VALIDATION_ERROR,
+              ErrorMessage.required('field' + ' ' + fieldName)
+            );
           }
         }
       };
@@ -376,10 +374,10 @@ RestWrite.prototype.validateAuthData = function () {
 
   if (!this.query && !this.data.authData) {
     if (typeof this.data.username !== 'string' || _.isEmpty(this.data.username)) {
-      throw new Parse.Error(Parse.Error.USERNAME_MISSING, 'bad or missing username');
+      throw new Parse.Error(Parse.Error.USERNAME_MISSING, ErrorMessage.required('username', ''));
     }
     if (typeof this.data.password !== 'string' || _.isEmpty(this.data.password)) {
-      throw new Parse.Error(Parse.Error.PASSWORD_MISSING, 'password is required');
+      throw new Parse.Error(Parse.Error.PASSWORD_MISSING, ErrorMessage.required('password', ''));
     }
   }
 
@@ -391,10 +389,7 @@ RestWrite.prototype.validateAuthData = function () {
     return;
   } else if (Object.prototype.hasOwnProperty.call(this.data, 'authData') && !this.data.authData) {
     // Handle saving authData to null
-    throw new Parse.Error(
-      Parse.Error.UNSUPPORTED_SERVICE,
-      'This authentication method is unsupported.'
-    );
+    throw new Parse.Error(Parse.Error.UNSUPPORTED_SERVICE, ErrorMessage.unsupportedService());
   }
 
   var authData = this.data.authData;
@@ -409,10 +404,7 @@ RestWrite.prototype.validateAuthData = function () {
       return this.handleAuthData(authData);
     }
   }
-  throw new Parse.Error(
-    Parse.Error.UNSUPPORTED_SERVICE,
-    'This authentication method is unsupported.'
-  );
+  throw new Parse.Error(Parse.Error.UNSUPPORTED_SERVICE, ErrorMessage.unsupportedService());
 };
 
 RestWrite.prototype.handleAuthDataValidation = function (authData) {
@@ -422,10 +414,7 @@ RestWrite.prototype.handleAuthDataValidation = function (authData) {
     }
     const validateAuthData = this.config.authDataManager.getValidatorForProvider(provider);
     if (!validateAuthData) {
-      throw new Parse.Error(
-        Parse.Error.UNSUPPORTED_SERVICE,
-        'This authentication method is unsupported.'
-      );
+      throw new Parse.Error(Parse.Error.UNSUPPORTED_SERVICE, ErrorMessage.unsupportedService());
     }
     return validateAuthData(authData[provider]);
   });
@@ -549,7 +538,7 @@ RestWrite.prototype.handleAuthData = function (authData) {
         // Trying to update auth data but users
         // are different
         if (userResult.objectId !== userId) {
-          throw new Parse.Error(Parse.Error.ACCOUNT_ALREADY_LINKED, 'this auth is already used');
+          throw new Parse.Error(Parse.Error.ACCOUNT_ALREADY_LINKED, ErrorMessage.accountLinked());
         }
         // No auth data was mutated, just keep going
         if (!hasMutatedAuthData) {
@@ -560,7 +549,7 @@ RestWrite.prototype.handleAuthData = function (authData) {
     return this.handleAuthDataValidation(authData).then(() => {
       if (results.length > 1) {
         // More than 1 user with the passed id's
-        throw new Parse.Error(Parse.Error.ACCOUNT_ALREADY_LINKED, 'this auth is already used');
+        throw new Parse.Error(Parse.Error.ACCOUNT_ALREADY_LINKED, ErrorMessage.accountLinked());
       }
     });
   });
@@ -575,8 +564,7 @@ RestWrite.prototype.transformUser = function () {
   }
 
   if (!this.auth.isMaster && 'emailVerified' in this.data) {
-    const error = `Clients aren't allowed to manually update email verification.`;
-    throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, error);
+    throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, ErrorMessage.clientEmailVerification());
   }
 
   // Do not cleanup session if objectId is not set
@@ -660,7 +648,7 @@ RestWrite.prototype._validateUserName = function () {
       if (results.length > 0) {
         throw new Parse.Error(
           Parse.Error.USERNAME_TAKEN,
-          'Account already exists for this username.'
+          ErrorMessage.exists('Account', 'username')
         );
       }
       return;
@@ -686,7 +674,7 @@ RestWrite.prototype._validateEmail = function () {
   // Validate basic email address format
   if (!this.data.email.match(/^.+@.+$/)) {
     return Promise.reject(
-      new Parse.Error(Parse.Error.INVALID_EMAIL_ADDRESS, 'Email address format is invalid.')
+      new Parse.Error(Parse.Error.INVALID_EMAIL_ADDRESS, ErrorMessage.invalid('Email address'))
     );
   }
   // Case insensitive match, see note above function.
@@ -705,7 +693,7 @@ RestWrite.prototype._validateEmail = function () {
       if (results.length > 0) {
         throw new Parse.Error(
           Parse.Error.EMAIL_TAKEN,
-          'Account already exists for this email address.'
+          ErrorMessage.exists('Account', 'email address')
         );
       }
       if (
@@ -739,8 +727,8 @@ RestWrite.prototype._validatePasswordRequirements = function () {
   // b. making a custom password reset page that shows the requirements
   const policyError = this.config.passwordPolicy.validationError
     ? this.config.passwordPolicy.validationError
-    : 'Password does not meet the Password Policy requirements.';
-  const containsUsernameError = 'Password cannot contain your username.';
+    : ErrorMessage.passwordPolicy();
+  const containsUsernameError = ErrorMessage.usernameInPassword();
 
   // check whether the password meets the password strength requirements
   if (
@@ -817,7 +805,9 @@ RestWrite.prototype._validatePasswordHistory = function () {
               return Promise.reject(
                 new Parse.Error(
                   Parse.Error.VALIDATION_ERROR,
-                  `New password should not be the same as last ${this.config.passwordPolicy.maxPasswordHistory} passwords.`
+                  ErrorMessage.passwordMatchesExistingPassword(
+                    this.config.passwordPolicy.maxPasswordHistory
+                  )
                 )
               );
             throw err;
@@ -985,12 +975,15 @@ RestWrite.prototype.handleSession = function () {
   }
 
   if (!this.auth.user && !this.auth.isMaster) {
-    throw new Parse.Error(Parse.Error.INVALID_SESSION_TOKEN, 'Session token required.');
+    throw new Parse.Error(
+      Parse.Error.INVALID_SESSION_TOKEN,
+      ErrorMessage.required('Session Token', '')
+    );
   }
 
   // TODO: Verify proper error to throw
   if (this.data.ACL) {
-    throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, 'Cannot set ' + 'ACL on a Session.');
+    throw new Parse.Error(Parse.Error.INVALID_KEY_NAME, ErrorMessage.aclSession());
   }
 
   if (this.query) {
@@ -1022,7 +1015,7 @@ RestWrite.prototype.handleSession = function () {
 
     return createSession().then(results => {
       if (!results.response) {
-        throw new Parse.Error(Parse.Error.INTERNAL_SERVER_ERROR, 'Error creating session.');
+        throw new Parse.Error(Parse.Error.INTERNAL_SERVER_ERROR, ErrorMessage.sessionError());
       }
       sessionData['objectId'] = results.response['objectId'];
       this.response = {
@@ -1050,10 +1043,7 @@ RestWrite.prototype.handleInstallation = function () {
     !this.data.installationId &&
     !this.auth.installationId
   ) {
-    throw new Parse.Error(
-      135,
-      'at least one ID field (deviceToken, installationId) ' + 'must be specified in this operation'
-    );
+    throw new Parse.Error(135, ErrorMessage.required('deviceToken or installationId'));
   }
 
   // If the device token is 64 characters long, we assume it is for iOS
@@ -1136,14 +1126,14 @@ RestWrite.prototype.handleInstallation = function () {
       // Sanity checks when running a query
       if (this.query && this.query.objectId) {
         if (!objectIdMatch) {
-          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Object not found for update.');
+          throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, ErrorMessage.notFound('Object'));
         }
         if (
           this.data.installationId &&
           objectIdMatch.installationId &&
           this.data.installationId !== objectIdMatch.installationId
         ) {
-          throw new Parse.Error(136, 'installationId may not be changed in this ' + 'operation');
+          throw new Parse.Error(136, ErrorMessage.noOp('installationId'));
         }
         if (
           this.data.deviceToken &&
@@ -1152,14 +1142,14 @@ RestWrite.prototype.handleInstallation = function () {
           !this.data.installationId &&
           !objectIdMatch.installationId
         ) {
-          throw new Parse.Error(136, 'deviceToken may not be changed in this ' + 'operation');
+          throw new Parse.Error(136, ErrorMessage.noOp('deviceToken'));
         }
         if (
           this.data.deviceType &&
           this.data.deviceType &&
           this.data.deviceType !== objectIdMatch.deviceType
         ) {
-          throw new Parse.Error(136, 'deviceType may not be changed in this ' + 'operation');
+          throw new Parse.Error(136, ErrorMessage.noOp('deviceType'));
         }
       }
 
@@ -1172,7 +1162,7 @@ RestWrite.prototype.handleInstallation = function () {
       }
       // need to specify deviceType only if it's new
       if (!this.query && !this.data.deviceType && !idMatch) {
-        throw new Parse.Error(135, 'deviceType must be specified in this operation');
+        throw new Parse.Error(135, ErrorMessage.reqOp('deviceType'));
       }
     })
     .then(() => {
@@ -1188,11 +1178,7 @@ RestWrite.prototype.handleInstallation = function () {
           // can just return the match.
           return deviceTokenMatches[0]['objectId'];
         } else if (!this.data.installationId) {
-          throw new Parse.Error(
-            132,
-            'Must specify installationId when deviceToken ' +
-              'matches multiple Installation objects'
-          );
+          throw new Parse.Error(132, ErrorMessage.installationIdWithDeviceToken());
         } else {
           // Multiple device token matches and we specified an installation ID,
           // or a single match where both the passed and matching objects have
@@ -1314,7 +1300,7 @@ RestWrite.prototype.runDatabaseOperation = function () {
   if (this.className === '_User' && this.query && this.auth.isUnauthenticated()) {
     throw new Parse.Error(
       Parse.Error.SESSION_MISSING,
-      `Cannot modify user ${this.query.objectId}.`
+      ErrorMessage.noUpdate('User', this.query.objectId)
     );
   }
 
@@ -1325,7 +1311,7 @@ RestWrite.prototype.runDatabaseOperation = function () {
   // TODO: Add better detection for ACL, ensuring a user can't be locked from
   //       their own user record.
   if (this.data.ACL && this.data.ACL['*unresolved']) {
-    throw new Parse.Error(Parse.Error.INVALID_ACL, 'Invalid ACL.');
+    throw new Parse.Error(Parse.Error.INVALID_ACL, ErrorMessage.invalidAcl());
   }
 
   if (this.query) {
@@ -1433,14 +1419,14 @@ RestWrite.prototype.runDatabaseOperation = function () {
         if (error && error.userInfo && error.userInfo.duplicated_field === 'username') {
           throw new Parse.Error(
             Parse.Error.USERNAME_TAKEN,
-            'Account already exists for this username.'
+            ErrorMessage.exists('Account', 'username')
           );
         }
 
         if (error && error.userInfo && error.userInfo.duplicated_field === 'email') {
           throw new Parse.Error(
             Parse.Error.EMAIL_TAKEN,
-            'Account already exists for this email address.'
+            ErrorMessage.exists('Account', 'email address')
           );
         }
 
@@ -1461,7 +1447,7 @@ RestWrite.prototype.runDatabaseOperation = function () {
             if (results.length > 0) {
               throw new Parse.Error(
                 Parse.Error.USERNAME_TAKEN,
-                'Account already exists for this username.'
+                ErrorMessage.exists('Account', 'username')
               );
             }
             return this.config.database.find(
@@ -1474,13 +1460,10 @@ RestWrite.prototype.runDatabaseOperation = function () {
             if (results.length > 0) {
               throw new Parse.Error(
                 Parse.Error.EMAIL_TAKEN,
-                'Account already exists for this email address.'
+                ErrorMessage.exists('Account', 'email address')
               );
             }
-            throw new Parse.Error(
-              Parse.Error.DUPLICATE_VALUE,
-              'A duplicate value for a field with unique values was provided'
-            );
+            throw new Parse.Error(Parse.Error.DUPLICATE_VALUE, ErrorMessage.duplicateValue());
           });
       })
       .then(response => {
diff --git a/src/Routers/UsersRouter.js b/src/Routers/UsersRouter.js
index cdce6a1348..ac88fac5c5 100644
--- a/src/Routers/UsersRouter.js
+++ b/src/Routers/UsersRouter.js
@@ -10,6 +10,7 @@ import passwordCrypto from '../password';
 import { maybeRunTrigger, Types as TriggerTypes } from '../triggers';
 import { promiseEnsureIdempotency } from '../middlewares';
 import RestWrite from '../RestWrite';
+import { ErrorMessage } from '../Errors/message';
 
 export class UsersRouter extends ClassesRouter {
   className() {
@@ -73,17 +74,23 @@ export class UsersRouter extends ClassesRouter {
 
       // TODO: use the right error codes / descriptions.
       if (!username && !email) {
-        throw new Parse.Error(Parse.Error.USERNAME_MISSING, 'username/email is required.');
+        throw new Parse.Error(
+          Parse.Error.USERNAME_MISSING,
+          ErrorMessage.required('username/email', '')
+        );
       }
       if (!password) {
-        throw new Parse.Error(Parse.Error.PASSWORD_MISSING, 'password is required.');
+        throw new Parse.Error(Parse.Error.PASSWORD_MISSING, ErrorMessage.required('password', ''));
       }
       if (
         typeof password !== 'string' ||
         (email && typeof email !== 'string') ||
         (username && typeof username !== 'string')
       ) {
-        throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Invalid username/password.');
+        throw new Parse.Error(
+          Parse.Error.OBJECT_NOT_FOUND,
+          ErrorMessage.invalid('username/password')
+        );
       }
 
       let user;
@@ -100,7 +107,10 @@ export class UsersRouter extends ClassesRouter {
         .find('_User', query)
         .then(results => {
           if (!results.length) {
-            throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Invalid username/password.');
+            throw new Parse.Error(
+              Parse.Error.OBJECT_NOT_FOUND,
+              ErrorMessage.invalid('username/password')
+            );
           }
 
           if (results.length > 1) {
@@ -122,21 +132,30 @@ export class UsersRouter extends ClassesRouter {
         })
         .then(() => {
           if (!isValidPassword) {
-            throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Invalid username/password.');
+            throw new Parse.Error(
+              Parse.Error.OBJECT_NOT_FOUND,
+              ErrorMessage.invalid('username/password')
+            );
           }
           // Ensure the user isn't locked out
           // A locked out user won't be able to login
           // To lock a user out, just set the ACL to `masterKey` only  ({}).
           // Empty ACL is OK
           if (!req.auth.isMaster && user.ACL && Object.keys(user.ACL).length == 0) {
-            throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Invalid username/password.');
+            throw new Parse.Error(
+              Parse.Error.OBJECT_NOT_FOUND,
+              ErrorMessage.invalid('username/password')
+            );
           }
           if (
             req.config.verifyUserEmails &&
             req.config.preventLoginWithUnverifiedEmail &&
             !user.emailVerified
           ) {
-            throw new Parse.Error(Parse.Error.EMAIL_NOT_FOUND, 'User email is not verified.');
+            throw new Parse.Error(
+              Parse.Error.EMAIL_NOT_FOUND,
+              ErrorMessage.unverified('User email')
+            );
           }
 
           this._sanitizeAuthData(user);
@@ -151,7 +170,10 @@ export class UsersRouter extends ClassesRouter {
 
   handleMe(req) {
     if (!req.info || !req.info.sessionToken) {
-      throw new Parse.Error(Parse.Error.INVALID_SESSION_TOKEN, 'Invalid session token');
+      throw new Parse.Error(
+        Parse.Error.INVALID_SESSION_TOKEN,
+        ErrorMessage.invalid('Session token', false)
+      );
     }
     const sessionToken = req.info.sessionToken;
     return rest
@@ -166,7 +188,10 @@ export class UsersRouter extends ClassesRouter {
       )
       .then(response => {
         if (!response.results || response.results.length == 0 || !response.results[0].user) {
-          throw new Parse.Error(Parse.Error.INVALID_SESSION_TOKEN, 'Invalid session token');
+          throw new Parse.Error(
+            Parse.Error.INVALID_SESSION_TOKEN,
+            ErrorMessage.invalid('Session token', false)
+          );
         } else {
           const user = response.results[0].user;
           // Send token back on the login, because SDKs expect that.
@@ -269,7 +294,10 @@ export class UsersRouter extends ClassesRouter {
    */
   async handleLogInAs(req) {
     if (!req.auth.isMaster) {
-      throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, 'master key is required');
+      throw new Parse.Error(
+        Parse.Error.OPERATION_FORBIDDEN,
+        ErrorMessage.required('Master Key', '')
+      );
     }
 
     const userId = req.body.userId || req.query.userId;
@@ -283,7 +311,7 @@ export class UsersRouter extends ClassesRouter {
     const queryResults = await req.config.database.find('_User', { objectId: userId });
     const user = queryResults[0];
     if (!user) {
-      throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'user not found');
+      throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, ErrorMessage.notFound('User'));
     }
 
     this._sanitizeAuthData(user);
@@ -376,7 +404,7 @@ export class UsersRouter extends ClassesRouter {
         // Maybe we need a Bad Configuration error, but the SDKs won't understand it. For now, Internal Server Error.
         throw new Parse.Error(
           Parse.Error.INTERNAL_SERVER_ERROR,
-          'An appName, publicServerURL, and emailAdapter are required for password reset and email verification functionality.'
+          ErrorMessage.fieldMissingForVerificationFunc()
         );
       } else {
         throw e;
@@ -389,13 +417,10 @@ export class UsersRouter extends ClassesRouter {
 
     const { email } = req.body;
     if (!email) {
-      throw new Parse.Error(Parse.Error.EMAIL_MISSING, 'you must provide an email');
+      throw new Parse.Error(Parse.Error.EMAIL_MISSING, ErrorMessage.required('email'));
     }
     if (typeof email !== 'string') {
-      throw new Parse.Error(
-        Parse.Error.INVALID_EMAIL_ADDRESS,
-        'you must provide a valid email string'
-      );
+      throw new Parse.Error(Parse.Error.INVALID_EMAIL_ADDRESS, ErrorMessage.invalid('email'));
     }
     const userController = req.config.userController;
     return userController.sendPasswordResetEmail(email).then(
@@ -423,7 +448,7 @@ export class UsersRouter extends ClassesRouter {
 
     const { email } = req.body;
     if (!email) {
-      throw new Parse.Error(Parse.Error.EMAIL_MISSING, 'you must provide an email');
+      throw new Parse.Error(Parse.Error.EMAIL_MISSING, ErrorMessage.required('email'));
     }
     if (typeof email !== 'string') {
       throw new Parse.Error(
@@ -434,7 +459,7 @@ export class UsersRouter extends ClassesRouter {
 
     return req.config.database.find('_User', { email: email }).then(results => {
       if (!results.length || results.length < 1) {
-        throw new Parse.Error(Parse.Error.EMAIL_NOT_FOUND, `No user found with email ${email}`);
+        throw new Parse.Error(Parse.Error.EMAIL_NOT_FOUND, ErrorMessage.notFound('User'));
       }
       const user = results[0];
 
@@ -442,7 +467,10 @@ export class UsersRouter extends ClassesRouter {
       delete user.password;
 
       if (user.emailVerified) {
-        throw new Parse.Error(Parse.Error.OTHER_CAUSE, `Email ${email} is already verified.`);
+        throw new Parse.Error(
+          Parse.Error.OTHER_CAUSE,
+          ErrorMessage.verified('Email ' + user.email)
+        );
       }
 
       const userController = req.config.userController;