diff --git a/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
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+++ b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
@@ -0,0 +1,40 @@
+# \FakeApi
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+
+
+
+## test_nullable_required_param
+
+> test_nullable_required_param(username, dummy_required_nullable_param)
+To test nullable required parameters
+
+
+
+### Parameters
+
+
+Name | Type | Description  | Required | Notes
+------------- | ------------- | ------------- | ------------- | -------------
+**username** | **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] |
+
+### Return type
+
+ (empty response body)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: Not defined
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
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
new file mode 100644
index 00000000000..a345fce8d9d
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+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
@@ -0,0 +1,59 @@
+/*
+ * 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 reqwest;
+
+use crate::apis::ResponseContent;
+use super::{Error, configuration};
+
+
+/// struct for typed errors of method [`test_nullable_required_param`]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum TestNullableRequiredParamError {
+    Status400(),
+    Status404(),
+    UnknownValue(serde_json::Value),
+}
+
+
+/// 
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, username: &str, dummy_required_nullable_param: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+    let local_var_configuration = configuration;
+
+    let local_var_client = &local_var_configuration.client;
+
+    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
+
+    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());
+    }
+    match dummy_required_nullable_param {
+        Some(local_var_param_value) => { local_var_req_builder = local_var_req_builder.header("dummy_required_nullable_param", local_var_param_value.to_string()); },
+        None => { local_var_req_builder = local_var_req_builder.header("dummy_required_nullable_param", ""); },
+    }
+
+    let local_var_req = local_var_req_builder.build()?;
+    let mut local_var_resp = local_var_client.execute(local_var_req)?;
+
+    let local_var_status = local_var_resp.status();
+    let local_var_content = local_var_resp.text()?;
+
+    if !local_var_status.is_client_error() && !local_var_status.is_server_error() {
+        Ok(())
+    } else {
+        let local_var_entity: Option<TestNullableRequiredParamError> = serde_json::from_str(&local_var_content).ok();
+        let local_var_error = ResponseContent { status: local_var_status, content: local_var_content, entity: local_var_entity };
+        Err(Error::ResponseError(local_var_error))
+    }
+}
+