diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
index 9a287f7a3fd0..18c6e48a636a 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
@@ -633,6 +633,18 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
         List<CodegenOperation> operations = objectMap.getOperation();
         for (CodegenOperation operation : operations) {
             if (operation.pathParams != null && operation.pathParams.size() > 0) {
+
+                // For types with `isAnyType` we assume it's a `serde_json::Value` type.
+                // However for path, query, and headers it's unlikely to be JSON so we default to `String`.
+                // Note that we keep the default `serde_json::Value` for body parameters.
+                for (var param : operation.allParams) {
+                    if (param.isAnyType && (param.isPathParam || param.isQueryParam || param.isHeaderParam)) {
+                        param.dataType = "String";
+                        param.isPrimitiveType = true;
+                        param.isString = true;
+                    }
+                }
+
                 for (var pathParam : operation.pathParams) {
                     if (!pathParam.baseName.contains("-")) {
                         continue;
diff --git a/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml b/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
index a282c5456be9..0e50c34403bd 100644
--- a/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
@@ -615,6 +615,11 @@ paths:
           description: To test escaping of parameters in rust code works
           schema:
             type: string
+        # For testing `isAnyType` types
+        - name: anyType
+          in: query
+          required: true
+          schema: {}
       responses:
         '200':
           description: successful operation
@@ -996,3 +1001,9 @@ components:
       properties:
         dummy:
           type: string
+    AnyTypeTest:
+      type: object
+      properties:
+        foo: {}
+      required: ["foo"]
+
diff --git a/samples/client/petstore/rust/hyper/petstore/.openapi-generator/FILES b/samples/client/petstore/rust/hyper/petstore/.openapi-generator/FILES
index 078bc10bcb44..5767a23c8ba5 100644
--- a/samples/client/petstore/rust/hyper/petstore/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/hyper/petstore/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -37,6 +38,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/hyper/petstore/README.md b/samples/client/petstore/rust/hyper/petstore/README.md
index 3c26db515d26..f6319d46f240 100644
--- a/samples/client/petstore/rust/hyper/petstore/README.md
+++ b/samples/client/petstore/rust/hyper/petstore/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/hyper/petstore/docs/AnyTypeTest.md b/samples/client/petstore/rust/hyper/petstore/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/hyper/petstore/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md b/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
index 7f8beb91115b..9dcab81e5dc9 100644
--- a/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
index b1e78f2c5f5a..8e422ef9d4bc 100644
--- a/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
@@ -37,19 +37,20 @@ impl<C: Connect> FakeApiClient<C>
 }
 
 pub trait FakeApi: Send + Sync {
-    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
 }
 
 impl<C: Connect>FakeApi for FakeApiClient<C>
     where C: Clone + std::marker::Send + Sync {
     #[allow(unused_mut)]
-    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
         let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{user_name}".to_string())
         ;
         if let Some(ref s) = content {
             let query_value = s.to_string();
             req = req.with_query_param("content".to_string(), query_value);
         }
+        req = req.with_query_param("anyType".to_string(), any_type.to_string());
         req = req.with_path_param("user_name".to_string(), user_name.to_string());
         match dummy_required_nullable_param {
             Some(param_value) => { req = req.with_header_param("dummy_required_nullable_param".to_string(), param_value.to_string()); },
diff --git a/samples/client/petstore/rust/hyper/petstore/src/models/any_type_test.rs b/samples/client/petstore/rust/hyper/petstore/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/hyper/petstore/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/hyper/petstore/src/models/mod.rs b/samples/client/petstore/rust/hyper/petstore/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/hyper/petstore/src/models/mod.rs
+++ b/samples/client/petstore/rust/hyper/petstore/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/hyper/petstore/tests/thread_test.rs b/samples/client/petstore/rust/hyper/petstore/tests/thread_test.rs
index 8329988a18bf..d0bc025ce50b 100644
--- a/samples/client/petstore/rust/hyper/petstore/tests/thread_test.rs
+++ b/samples/client/petstore/rust/hyper/petstore/tests/thread_test.rs
@@ -11,7 +11,7 @@ mod tests {
         let handle = thread::spawn(move || {
             let _ = client
                 .fake_api()
-                .test_nullable_required_param("username", None, None, None);
+                .test_nullable_required_param("username", None, "any_type", None, None);
         });
 
         handle.join().expect("Thread panicked!");
diff --git a/samples/client/petstore/rust/hyper0x/petstore/.openapi-generator/FILES b/samples/client/petstore/rust/hyper0x/petstore/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/hyper0x/petstore/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/hyper0x/petstore/README.md b/samples/client/petstore/rust/hyper0x/petstore/README.md
index 0143eb0f8137..c41a4d7e0e90 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/README.md
+++ b/samples/client/petstore/rust/hyper0x/petstore/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/hyper0x/petstore/docs/AnyTypeTest.md b/samples/client/petstore/rust/hyper0x/petstore/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/hyper0x/petstore/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md b/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
index 12a59925332f..099602bb22a7 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
@@ -36,19 +36,20 @@ impl<C: hyper::client::connect::Connect> FakeApiClient<C>
 }
 
 pub trait FakeApi {
-    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>>;
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>>;
 }
 
 impl<C: hyper::client::connect::Connect>FakeApi for FakeApiClient<C>
     where C: Clone + std::marker::Send + Sync {
     #[allow(unused_mut)]
-    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
         let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{user_name}".to_string())
         ;
         if let Some(ref s) = content {
             let query_value = s.to_string();
             req = req.with_query_param("content".to_string(), query_value);
         }
+        req = req.with_query_param("anyType".to_string(), any_type.to_string());
         req = req.with_path_param("user_name".to_string(), user_name.to_string());
         match dummy_required_nullable_param {
             Some(param_value) => { req = req.with_header_param("dummy_required_nullable_param".to_string(), param_value.to_string()); },
diff --git a/samples/client/petstore/rust/hyper0x/petstore/src/models/any_type_test.rs b/samples/client/petstore/rust/hyper0x/petstore/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/hyper0x/petstore/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/hyper0x/petstore/src/models/mod.rs b/samples/client/petstore/rust/hyper0x/petstore/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/src/models/mod.rs
+++ b/samples/client/petstore/rust/hyper0x/petstore/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest-trait/petstore/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/README.md b/samples/client/petstore/rust/reqwest-trait/petstore/README.md
index d4fe770230cf..abfb091ca356 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/README.md
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest-trait/petstore/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md b/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
index 6dd5512c1982..7368946bb46f 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
@@ -23,7 +23,7 @@ use super::{Error, configuration};
 pub trait FakeApi: Send + Sync {
 
     /// GET /fake/user/{user_name}
-    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'uppercase, 'content>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>, content: Option<&'content str>) -> Result<(), Error<TestNullableRequiredParamError>>;
+    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'any_type, 'uppercase, 'content>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, any_type: &'any_type str, uppercase: Option<&'uppercase str>, content: Option<&'content str>) -> Result<(), Error<TestNullableRequiredParamError>>;
 }
 
 pub struct FakeApiClient {
@@ -41,7 +41,7 @@ impl FakeApiClient {
 #[async_trait]
 impl FakeApi for FakeApiClient {
     /// 
-    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'uppercase, 'content>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>, content: Option<&'content str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'any_type, 'uppercase, 'content>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, any_type: &'any_type str, uppercase: Option<&'uppercase str>, content: Option<&'content str>) -> Result<(), Error<TestNullableRequiredParamError>> {
         let local_var_configuration = &self.configuration;
 
         let local_var_client = &local_var_configuration.client;
@@ -52,6 +52,7 @@ impl FakeApi for FakeApiClient {
         if let Some(ref local_var_str) = content {
             local_var_req_builder = local_var_req_builder.query(&[("content", &local_var_str.to_string())]);
         }
+        local_var_req_builder = local_var_req_builder.query(&[("anyType", &any_type.to_string())]);
         if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
             local_var_req_builder = local_var_req_builder.header(reqwest::header::USER_AGENT, local_var_user_agent.clone());
         }
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest-trait/petstore/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/src/models/mod.rs b/samples/client/petstore/rust/reqwest-trait/petstore/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-async-middleware/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md b/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
index 32d4fa4e5da7..f478f035b2b8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
index dbc4858a0eed..be9503699260 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
@@ -21,6 +21,7 @@ pub struct TestNullableRequiredParamParams {
     pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
+    pub any_type: String,
     /// To test parameter names in upper case
     pub uppercase: Option<String>,
     /// To test escaping of parameters in rust code works
@@ -55,6 +56,7 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     if let Some(ref param_value) = params.content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &params.any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
index 1517c8be4854..e38f79988b82 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
index dbc4858a0eed..be9503699260 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
@@ -21,6 +21,7 @@ pub struct TestNullableRequiredParamParams {
     pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
+    pub any_type: String,
     /// To test parameter names in upper case
     pub uppercase: Option<String>,
     /// To test escaping of parameters in rust code works
@@ -55,6 +56,7 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     if let Some(ref param_value) = params.content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &params.any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-async/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-async/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/README.md b/samples/client/petstore/rust/reqwest/petstore-async/README.md
index 8975bbb48926..72996d36543f 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-async/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
index dbc4858a0eed..be9503699260 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
@@ -21,6 +21,7 @@ pub struct TestNullableRequiredParamParams {
     pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
+    pub any_type: String,
     /// To test parameter names in upper case
     pub uppercase: Option<String>,
     /// To test escaping of parameters in rust code works
@@ -55,6 +56,7 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     if let Some(ref param_value) = params.content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &params.any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-avoid-box/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md b/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
index 03f217550a46..3dd5fd8df914 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
index dbc4858a0eed..be9503699260 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
@@ -21,6 +21,7 @@ pub struct TestNullableRequiredParamParams {
     pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
+    pub any_type: String,
     /// To test parameter names in upper case
     pub uppercase: Option<String>,
     /// To test escaping of parameters in rust code works
@@ -55,6 +56,7 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     if let Some(ref param_value) = params.content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &params.any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
index 494104867fad..5ed03ffe8db8 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
index f607b9b069d4..84059e46e596 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
@@ -26,10 +26,11 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_user_name = user_name;
     let p_dummy_required_nullable_param = dummy_required_nullable_param;
+    let p_any_type = any_type;
     let p_uppercase = uppercase;
     let p_content = content;
 
@@ -39,6 +40,7 @@ pub fn test_nullable_required_param(configuration: &configuration::Configuration
     if let Some(ref param_value) = p_content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &p_any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/.openapi-generator/FILES
index 13e753f39020..1c83a6638ad2 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/.openapi-generator/FILES
@@ -4,6 +4,7 @@ Cargo.toml
 README.md
 docs/FakeApi.md
 docs/FooActionContainer.md
+docs/FooAnyTypeTest.md
 docs/FooApiResponse.md
 docs/FooArrayItemRefTest.md
 docs/FooBaz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/foo_action_container.rs
+src/models/foo_any_type_test.rs
 src/models/foo_api_response.rs
 src/models/foo_array_item_ref_test.rs
 src/models/foo_baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
index a1383c0003e7..1303b7a8174e 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [FooActionContainer](docs/FooActionContainer.md)
+ - [FooAnyTypeTest](docs/FooAnyTypeTest.md)
  - [FooApiResponse](docs/FooApiResponse.md)
  - [FooArrayItemRefTest](docs/FooArrayItemRefTest.md)
  - [FooBaz](docs/FooBaz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FooAnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FooAnyTypeTest.md
new file mode 100644
index 000000000000..ca27b3a52bc1
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FooAnyTypeTest.md
@@ -0,0 +1,11 @@
+# FooAnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
index f607b9b069d4..84059e46e596 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
@@ -26,10 +26,11 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_user_name = user_name;
     let p_dummy_required_nullable_param = dummy_required_nullable_param;
+    let p_any_type = any_type;
     let p_uppercase = uppercase;
     let p_content = content;
 
@@ -39,6 +40,7 @@ pub fn test_nullable_required_param(configuration: &configuration::Configuration
     if let Some(ref param_value) = p_content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &p_any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/foo_any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/foo_any_type_test.rs
new file mode 100644
index 000000000000..6f0cbd7a74ac
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/foo_any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct FooAnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl FooAnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> FooAnyTypeTest {
+        FooAnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/mod.rs
index 11d4654e7908..256941bfbc1e 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod foo_action_container;
 pub use self::foo_action_container::FooActionContainer;
+pub mod foo_any_type_test;
+pub use self::foo_any_type_test::FooAnyTypeTest;
 pub mod foo_api_response;
 pub use self::foo_api_response::FooApiResponse;
 pub mod foo_array_item_ref_test;
diff --git a/samples/client/petstore/rust/reqwest/petstore/.openapi-generator/FILES b/samples/client/petstore/rust/reqwest/petstore/.openapi-generator/FILES
index 6d5eacd5c073..d935311d38c8 100644
--- a/samples/client/petstore/rust/reqwest/petstore/.openapi-generator/FILES
+++ b/samples/client/petstore/rust/reqwest/petstore/.openapi-generator/FILES
@@ -3,6 +3,7 @@
 Cargo.toml
 README.md
 docs/ActionContainer.md
+docs/AnyTypeTest.md
 docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
@@ -35,6 +36,7 @@ src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
 src/models/action_container.rs
+src/models/any_type_test.rs
 src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
diff --git a/samples/client/petstore/rust/reqwest/petstore/README.md b/samples/client/petstore/rust/reqwest/petstore/README.md
index d4fe770230cf..abfb091ca356 100644
--- a/samples/client/petstore/rust/reqwest/petstore/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore/README.md
@@ -54,6 +54,7 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [ActionContainer](docs/ActionContainer.md)
+ - [AnyTypeTest](docs/AnyTypeTest.md)
  - [ApiResponse](docs/ApiResponse.md)
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
diff --git a/samples/client/petstore/rust/reqwest/petstore/docs/AnyTypeTest.md b/samples/client/petstore/rust/reqwest/petstore/docs/AnyTypeTest.md
new file mode 100644
index 000000000000..cfcbd80fed0e
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore/docs/AnyTypeTest.md
@@ -0,0 +1,11 @@
+# AnyTypeTest
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**serde_json::Value**](.md)> |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
index c41f7d7b0e2f..ac1e9f40c105 100644
--- a/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
@@ -10,7 +10,7 @@ Method | HTTP request | Description
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase, content)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, any_type, uppercase, content)
 To test nullable required parameters
 
 
@@ -22,6 +22,7 @@ Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
 **user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
+**any_type** | **String** |  | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 **content** | Option<**String**> | To test escaping of parameters in rust code works |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
index f607b9b069d4..84059e46e596 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
@@ -26,10 +26,11 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, any_type: &str, uppercase: Option<&str>, content: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_user_name = user_name;
     let p_dummy_required_nullable_param = dummy_required_nullable_param;
+    let p_any_type = any_type;
     let p_uppercase = uppercase;
     let p_content = content;
 
@@ -39,6 +40,7 @@ pub fn test_nullable_required_param(configuration: &configuration::Configuration
     if let Some(ref param_value) = p_content {
         req_builder = req_builder.query(&[("content", &param_value.to_string())]);
     }
+    req_builder = req_builder.query(&[("anyType", &p_any_type.to_string())]);
     if let Some(ref user_agent) = configuration.user_agent {
         req_builder = req_builder.header(reqwest::header::USER_AGENT, user_agent.clone());
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/models/any_type_test.rs b/samples/client/petstore/rust/reqwest/petstore/src/models/any_type_test.rs
new file mode 100644
index 000000000000..8a873991fd42
--- /dev/null
+++ b/samples/client/petstore/rust/reqwest/petstore/src/models/any_type_test.rs
@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AnyTypeTest {
+    #[serde(rename = "foo", deserialize_with = "Option::deserialize")]
+    pub foo: Option<serde_json::Value>,
+}
+
+impl AnyTypeTest {
+    pub fn new(foo: Option<serde_json::Value>) -> AnyTypeTest {
+        AnyTypeTest {
+            foo,
+        }
+    }
+}
+
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/models/mod.rs b/samples/client/petstore/rust/reqwest/petstore/src/models/mod.rs
index b7e684d8071d..da642be6a19c 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/models/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod action_container;
 pub use self::action_container::ActionContainer;
+pub mod any_type_test;
+pub use self::any_type_test::AnyTypeTest;
 pub mod api_response;
 pub use self::api_response::ApiResponse;
 pub mod array_item_ref_test;