diff --git a/examples/assistant.rs b/examples/assistant.rs
index 2e212b8..b7573e6 100644
--- a/examples/assistant.rs
+++ b/examples/assistant.rs
@@ -10,7 +10,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let mut tools = HashMap::new();
     tools.insert("type".to_string(), "code_interpreter".to_string());
diff --git a/examples/audio_speech.rs b/examples/audio_speech.rs
index 9e3af08..7df168f 100644
--- a/examples/audio_speech.rs
+++ b/examples/audio_speech.rs
@@ -5,7 +5,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = AudioSpeechRequest::new(
         TTS_1.to_string(),
diff --git a/examples/audio_transcriptions.rs b/examples/audio_transcriptions.rs
index f74fc11..2c341de 100644
--- a/examples/audio_transcriptions.rs
+++ b/examples/audio_transcriptions.rs
@@ -7,7 +7,7 @@ use std::io::Read;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let file_path = "examples/data/problem.mp3";
 
diff --git a/examples/audio_translations.rs b/examples/audio_translations.rs
index 13b57e0..d352b65 100644
--- a/examples/audio_translations.rs
+++ b/examples/audio_translations.rs
@@ -5,7 +5,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = AudioTranslationRequest::new(
         "examples/data/problem_cn.mp3".to_string(),
diff --git a/examples/batch.rs b/examples/batch.rs
index f14617e..aca5784 100644
--- a/examples/batch.rs
+++ b/examples/batch.rs
@@ -10,7 +10,7 @@ use std::str;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = FileUploadRequest::new(
         "examples/data/batch_request.json".to_string(),
diff --git a/examples/chat_completion.rs b/examples/chat_completion.rs
index 7a5791c..64f564e 100644
--- a/examples/chat_completion.rs
+++ b/examples/chat_completion.rs
@@ -6,7 +6,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = ChatCompletionRequest::new(
         GPT4_O_MINI.to_string(),
@@ -21,7 +21,11 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let result = client.chat_completion(req).await?;
     println!("Content: {:?}", result.choices[0].message.content);
-    println!("Response Headers: {:?}", result.headers);
+
+    // print response headers
+    for (key, value) in client.headers.unwrap().iter() {
+        println!("{}: {:?}", key, value);
+    }
 
     Ok(())
 }
diff --git a/examples/completion.rs b/examples/completion.rs
index 138c1fe..95cbc23 100644
--- a/examples/completion.rs
+++ b/examples/completion.rs
@@ -5,7 +5,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = CompletionRequest::new(
         completion::GPT3_TEXT_DAVINCI_003.to_string(),
diff --git a/examples/embedding.rs b/examples/embedding.rs
index 8615bdb..23ca6db 100644
--- a/examples/embedding.rs
+++ b/examples/embedding.rs
@@ -6,7 +6,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let mut req = EmbeddingRequest::new(
         TEXT_EMBEDDING_3_SMALL.to_string(),
diff --git a/examples/function_call.rs b/examples/function_call.rs
index 1858465..06bd922 100644
--- a/examples/function_call.rs
+++ b/examples/function_call.rs
@@ -18,7 +18,7 @@ fn get_coin_price(coin: &str) -> f64 {
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let mut properties = HashMap::new();
     properties.insert(
diff --git a/examples/function_call_role.rs b/examples/function_call_role.rs
index 1afc91a..46148f4 100644
--- a/examples/function_call_role.rs
+++ b/examples/function_call_role.rs
@@ -18,7 +18,7 @@ fn get_coin_price(coin: &str) -> f64 {
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let mut properties = HashMap::new();
     properties.insert(
diff --git a/examples/openrouter.rs b/examples/openrouter.rs
index 4064ce6..dd04e0a 100644
--- a/examples/openrouter.rs
+++ b/examples/openrouter.rs
@@ -6,7 +6,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENROUTER_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder()
+    let mut client = OpenAIClient::builder()
         .with_endpoint("https://openrouter.ai/api/v1")
         .with_api_key(api_key)
         .build()?;
@@ -24,7 +24,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let result = client.chat_completion(req).await?;
     println!("Content: {:?}", result.choices[0].message.content);
-    println!("Response Headers: {:?}", result.headers);
+    println!("Response Headers: {:?}", client.headers);
 
     Ok(())
 }
diff --git a/examples/vision.rs b/examples/vision.rs
index 6a92c43..7bad362 100644
--- a/examples/vision.rs
+++ b/examples/vision.rs
@@ -6,7 +6,7 @@ use std::env;
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api_key = env::var("OPENAI_API_KEY").unwrap().to_string();
-    let client = OpenAIClient::builder().with_api_key(api_key).build()?;
+    let mut client = OpenAIClient::builder().with_api_key(api_key).build()?;
 
     let req = ChatCompletionRequest::new(
         GPT4_O.to_string(),
diff --git a/src/v1/api.rs b/src/v1/api.rs
index cbd6a4c..c53f989 100644
--- a/src/v1/api.rs
+++ b/src/v1/api.rs
@@ -68,7 +68,7 @@ pub struct OpenAIClient {
     organization: Option<String>,
     proxy: Option<String>,
     timeout: Option<u64>,
-    headers: Option<HeaderMap>,
+    pub headers: Option<HeaderMap>,
 }
 
 impl OpenAIClientBuilder {
@@ -175,7 +175,7 @@ impl OpenAIClient {
     }
 
     async fn post<T: serde::de::DeserializeOwned>(
-        &self,
+        &mut self,
         path: &str,
         body: &impl serde::ser::Serialize,
     ) -> Result<T, APIError> {
@@ -185,7 +185,7 @@ impl OpenAIClient {
         self.handle_response(response).await
     }
 
-    async fn get<T: serde::de::DeserializeOwned>(&self, path: &str) -> Result<T, APIError> {
+    async fn get<T: serde::de::DeserializeOwned>(&mut self, path: &str) -> Result<T, APIError> {
         let request = self.build_request(Method::GET, path).await;
         let response = request.send().await?;
         self.handle_response(response).await
@@ -197,14 +197,14 @@ impl OpenAIClient {
         Ok(response.bytes().await?)
     }
 
-    async fn delete<T: serde::de::DeserializeOwned>(&self, path: &str) -> Result<T, APIError> {
+    async fn delete<T: serde::de::DeserializeOwned>(&mut self, path: &str) -> Result<T, APIError> {
         let request = self.build_request(Method::DELETE, path).await;
         let response = request.send().await?;
         self.handle_response(response).await
     }
 
     async fn post_form<T: serde::de::DeserializeOwned>(
-        &self,
+        &mut self,
         path: &str,
         form: Form,
     ) -> Result<T, APIError> {
@@ -222,14 +222,18 @@ impl OpenAIClient {
     }
 
     async fn handle_response<T: serde::de::DeserializeOwned>(
-        &self,
+        &mut self,
         response: Response,
     ) -> Result<T, APIError> {
         let status = response.status();
+        let headers = response.headers().clone();
         if status.is_success() {
             let text = response.text().await.unwrap_or_else(|_| "".to_string());
             match serde_json::from_str::<T>(&text) {
-                Ok(parsed) => Ok(parsed),
+                Ok(parsed) => {
+                    self.headers = Some(headers);
+                    Ok(parsed)
+                }
                 Err(e) => Err(APIError::CustomError {
                     message: format!("Failed to parse JSON: {} / response {}", e, text),
                 }),
@@ -245,42 +249,51 @@ impl OpenAIClient {
         }
     }
 
-    pub async fn completion(&self, req: CompletionRequest) -> Result<CompletionResponse, APIError> {
+    pub async fn completion(
+        &mut self,
+        req: CompletionRequest,
+    ) -> Result<CompletionResponse, APIError> {
         self.post("completions", &req).await
     }
 
-    pub async fn edit(&self, req: EditRequest) -> Result<EditResponse, APIError> {
+    pub async fn edit(&mut self, req: EditRequest) -> Result<EditResponse, APIError> {
         self.post("edits", &req).await
     }
 
     pub async fn image_generation(
-        &self,
+        &mut self,
         req: ImageGenerationRequest,
     ) -> Result<ImageGenerationResponse, APIError> {
         self.post("images/generations", &req).await
     }
 
-    pub async fn image_edit(&self, req: ImageEditRequest) -> Result<ImageEditResponse, APIError> {
+    pub async fn image_edit(
+        &mut self,
+        req: ImageEditRequest,
+    ) -> Result<ImageEditResponse, APIError> {
         self.post("images/edits", &req).await
     }
 
     pub async fn image_variation(
-        &self,
+        &mut self,
         req: ImageVariationRequest,
     ) -> Result<ImageVariationResponse, APIError> {
         self.post("images/variations", &req).await
     }
 
-    pub async fn embedding(&self, req: EmbeddingRequest) -> Result<EmbeddingResponse, APIError> {
+    pub async fn embedding(
+        &mut self,
+        req: EmbeddingRequest,
+    ) -> Result<EmbeddingResponse, APIError> {
         self.post("embeddings", &req).await
     }
 
-    pub async fn file_list(&self) -> Result<FileListResponse, APIError> {
+    pub async fn file_list(&mut self) -> Result<FileListResponse, APIError> {
         self.get("files").await
     }
 
     pub async fn upload_file(
-        &self,
+        &mut self,
         req: FileUploadRequest,
     ) -> Result<FileUploadResponse, APIError> {
         let form = Self::create_form(&req, "file")?;
@@ -288,13 +301,16 @@ impl OpenAIClient {
     }
 
     pub async fn delete_file(
-        &self,
+        &mut self,
         req: FileDeleteRequest,
     ) -> Result<FileDeleteResponse, APIError> {
         self.delete(&format!("files/{}", req.file_id)).await
     }
 
-    pub async fn retrieve_file(&self, file_id: String) -> Result<FileRetrieveResponse, APIError> {
+    pub async fn retrieve_file(
+        &mut self,
+        file_id: String,
+    ) -> Result<FileRetrieveResponse, APIError> {
         self.get(&format!("files/{}", file_id)).await
     }
 
@@ -303,14 +319,14 @@ impl OpenAIClient {
     }
 
     pub async fn chat_completion(
-        &self,
+        &mut self,
         req: ChatCompletionRequest,
     ) -> Result<ChatCompletionResponse, APIError> {
         self.post("chat/completions", &req).await
     }
 
     pub async fn audio_transcription(
-        &self,
+        &mut self,
         req: AudioTranscriptionRequest,
     ) -> Result<AudioTranscriptionResponse, APIError> {
         // https://platform.openai.com/docs/api-reference/audio/createTranscription#audio-createtranscription-response_format
@@ -335,7 +351,7 @@ impl OpenAIClient {
     }
 
     pub async fn audio_transcription_raw(
-        &self,
+        &mut self,
         req: AudioTranscriptionRequest,
     ) -> Result<Bytes, APIError> {
         // https://platform.openai.com/docs/api-reference/audio/createTranscription#audio-createtranscription-response_format
@@ -360,7 +376,7 @@ impl OpenAIClient {
     }
 
     pub async fn audio_translation(
-        &self,
+        &mut self,
         req: AudioTranslationRequest,
     ) -> Result<AudioTranslationResponse, APIError> {
         let form = Self::create_form(&req, "file")?;
@@ -368,7 +384,7 @@ impl OpenAIClient {
     }
 
     pub async fn audio_speech(
-        &self,
+        &mut self,
         req: AudioSpeechRequest,
     ) -> Result<AudioSpeechResponse, APIError> {
         let request = self.build_request(Method::POST, "audio/speech").await;
@@ -410,20 +426,20 @@ impl OpenAIClient {
     }
 
     pub async fn create_fine_tuning_job(
-        &self,
+        &mut self,
         req: CreateFineTuningJobRequest,
     ) -> Result<FineTuningJobObject, APIError> {
         self.post("fine_tuning/jobs", &req).await
     }
 
     pub async fn list_fine_tuning_jobs(
-        &self,
+        &mut self,
     ) -> Result<FineTuningPagination<FineTuningJobObject>, APIError> {
         self.get("fine_tuning/jobs").await
     }
 
     pub async fn list_fine_tuning_job_events(
-        &self,
+        &mut self,
         req: ListFineTuningJobEventsRequest,
     ) -> Result<FineTuningPagination<FineTuningJobEvent>, APIError> {
         self.get(&format!(
@@ -434,7 +450,7 @@ impl OpenAIClient {
     }
 
     pub async fn retrieve_fine_tuning_job(
-        &self,
+        &mut self,
         req: RetrieveFineTuningJobRequest,
     ) -> Result<FineTuningJobObject, APIError> {
         self.get(&format!("fine_tuning/jobs/{}", req.fine_tuning_job_id))
@@ -442,7 +458,7 @@ impl OpenAIClient {
     }
 
     pub async fn cancel_fine_tuning_job(
-        &self,
+        &mut self,
         req: CancelFineTuningJobRequest,
     ) -> Result<FineTuningJobObject, APIError> {
         self.post(
@@ -453,28 +469,28 @@ impl OpenAIClient {
     }
 
     pub async fn create_moderation(
-        &self,
+        &mut self,
         req: CreateModerationRequest,
     ) -> Result<CreateModerationResponse, APIError> {
         self.post("moderations", &req).await
     }
 
     pub async fn create_assistant(
-        &self,
+        &mut self,
         req: AssistantRequest,
     ) -> Result<AssistantObject, APIError> {
         self.post("assistants", &req).await
     }
 
     pub async fn retrieve_assistant(
-        &self,
+        &mut self,
         assistant_id: String,
     ) -> Result<AssistantObject, APIError> {
         self.get(&format!("assistants/{}", assistant_id)).await
     }
 
     pub async fn modify_assistant(
-        &self,
+        &mut self,
         assistant_id: String,
         req: AssistantRequest,
     ) -> Result<AssistantObject, APIError> {
@@ -482,12 +498,15 @@ impl OpenAIClient {
             .await
     }
 
-    pub async fn delete_assistant(&self, assistant_id: String) -> Result<DeletionStatus, APIError> {
+    pub async fn delete_assistant(
+        &mut self,
+        assistant_id: String,
+    ) -> Result<DeletionStatus, APIError> {
         self.delete(&format!("assistants/{}", assistant_id)).await
     }
 
     pub async fn list_assistant(
-        &self,
+        &mut self,
         limit: Option<i64>,
         order: Option<String>,
         after: Option<String>,
@@ -498,7 +517,7 @@ impl OpenAIClient {
     }
 
     pub async fn create_assistant_file(
-        &self,
+        &mut self,
         assistant_id: String,
         req: AssistantFileRequest,
     ) -> Result<AssistantFileObject, APIError> {
@@ -507,7 +526,7 @@ impl OpenAIClient {
     }
 
     pub async fn retrieve_assistant_file(
-        &self,
+        &mut self,
         assistant_id: String,
         file_id: String,
     ) -> Result<AssistantFileObject, APIError> {
@@ -516,7 +535,7 @@ impl OpenAIClient {
     }
 
     pub async fn delete_assistant_file(
-        &self,
+        &mut self,
         assistant_id: String,
         file_id: String,
     ) -> Result<DeletionStatus, APIError> {
@@ -525,7 +544,7 @@ impl OpenAIClient {
     }
 
     pub async fn list_assistant_file(
-        &self,
+        &mut self,
         assistant_id: String,
         limit: Option<i64>,
         order: Option<String>,
@@ -542,28 +561,31 @@ impl OpenAIClient {
         self.get(&url).await
     }
 
-    pub async fn create_thread(&self, req: CreateThreadRequest) -> Result<ThreadObject, APIError> {
+    pub async fn create_thread(
+        &mut self,
+        req: CreateThreadRequest,
+    ) -> Result<ThreadObject, APIError> {
         self.post("threads", &req).await
     }
 
-    pub async fn retrieve_thread(&self, thread_id: String) -> Result<ThreadObject, APIError> {
+    pub async fn retrieve_thread(&mut self, thread_id: String) -> Result<ThreadObject, APIError> {
         self.get(&format!("threads/{}", thread_id)).await
     }
 
     pub async fn modify_thread(
-        &self,
+        &mut self,
         thread_id: String,
         req: ModifyThreadRequest,
     ) -> Result<ThreadObject, APIError> {
         self.post(&format!("threads/{}", thread_id), &req).await
     }
 
-    pub async fn delete_thread(&self, thread_id: String) -> Result<DeletionStatus, APIError> {
+    pub async fn delete_thread(&mut self, thread_id: String) -> Result<DeletionStatus, APIError> {
         self.delete(&format!("threads/{}", thread_id)).await
     }
 
     pub async fn create_message(
-        &self,
+        &mut self,
         thread_id: String,
         req: CreateMessageRequest,
     ) -> Result<MessageObject, APIError> {
@@ -572,7 +594,7 @@ impl OpenAIClient {
     }
 
     pub async fn retrieve_message(
-        &self,
+        &mut self,
         thread_id: String,
         message_id: String,
     ) -> Result<MessageObject, APIError> {
@@ -581,7 +603,7 @@ impl OpenAIClient {
     }
 
     pub async fn modify_message(
-        &self,
+        &mut self,
         thread_id: String,
         message_id: String,
         req: ModifyMessageRequest,
@@ -593,12 +615,12 @@ impl OpenAIClient {
         .await
     }
 
-    pub async fn list_messages(&self, thread_id: String) -> Result<ListMessage, APIError> {
+    pub async fn list_messages(&mut self, thread_id: String) -> Result<ListMessage, APIError> {
         self.get(&format!("threads/{}/messages", thread_id)).await
     }
 
     pub async fn retrieve_message_file(
-        &self,
+        &mut self,
         thread_id: String,
         message_id: String,
         file_id: String,
@@ -611,7 +633,7 @@ impl OpenAIClient {
     }
 
     pub async fn list_message_file(
-        &self,
+        &mut self,
         thread_id: String,
         message_id: String,
         limit: Option<i64>,
@@ -630,7 +652,7 @@ impl OpenAIClient {
     }
 
     pub async fn create_run(
-        &self,
+        &mut self,
         thread_id: String,
         req: CreateRunRequest,
     ) -> Result<RunObject, APIError> {
@@ -639,7 +661,7 @@ impl OpenAIClient {
     }
 
     pub async fn retrieve_run(
-        &self,
+        &mut self,
         thread_id: String,
         run_id: String,
     ) -> Result<RunObject, APIError> {
@@ -648,7 +670,7 @@ impl OpenAIClient {
     }
 
     pub async fn modify_run(
-        &self,
+        &mut self,
         thread_id: String,
         run_id: String,
         req: ModifyRunRequest,
@@ -658,7 +680,7 @@ impl OpenAIClient {
     }
 
     pub async fn list_run(
-        &self,
+        &mut self,
         thread_id: String,
         limit: Option<i64>,
         order: Option<String>,
@@ -676,7 +698,7 @@ impl OpenAIClient {
     }
 
     pub async fn cancel_run(
-        &self,
+        &mut self,
         thread_id: String,
         run_id: String,
     ) -> Result<RunObject, APIError> {
@@ -688,14 +710,14 @@ impl OpenAIClient {
     }
 
     pub async fn create_thread_and_run(
-        &self,
+        &mut self,
         req: CreateThreadAndRunRequest,
     ) -> Result<RunObject, APIError> {
         self.post("threads/runs", &req).await
     }
 
     pub async fn retrieve_run_step(
-        &self,
+        &mut self,
         thread_id: String,
         run_id: String,
         step_id: String,
@@ -708,7 +730,7 @@ impl OpenAIClient {
     }
 
     pub async fn list_run_step(
-        &self,
+        &mut self,
         thread_id: String,
         run_id: String,
         limit: Option<i64>,
@@ -726,15 +748,18 @@ impl OpenAIClient {
         self.get(&url).await
     }
 
-    pub async fn create_batch(&self, req: CreateBatchRequest) -> Result<BatchResponse, APIError> {
+    pub async fn create_batch(
+        &mut self,
+        req: CreateBatchRequest,
+    ) -> Result<BatchResponse, APIError> {
         self.post("batches", &req).await
     }
 
-    pub async fn retrieve_batch(&self, batch_id: String) -> Result<BatchResponse, APIError> {
+    pub async fn retrieve_batch(&mut self, batch_id: String) -> Result<BatchResponse, APIError> {
         self.get(&format!("batches/{}", batch_id)).await
     }
 
-    pub async fn cancel_batch(&self, batch_id: String) -> Result<BatchResponse, APIError> {
+    pub async fn cancel_batch(&mut self, batch_id: String) -> Result<BatchResponse, APIError> {
         self.post(
             &format!("batches/{}/cancel", batch_id),
             &common::EmptyRequestBody {},
@@ -743,7 +768,7 @@ impl OpenAIClient {
     }
 
     pub async fn list_batch(
-        &self,
+        &mut self,
         after: Option<String>,
         limit: Option<i64>,
     ) -> Result<ListBatchResponse, APIError> {
diff --git a/src/v1/assistant.rs b/src/v1/assistant.rs
index 0c18ffe..319073e 100644
--- a/src/v1/assistant.rs
+++ b/src/v1/assistant.rs
@@ -61,7 +61,6 @@ pub struct AssistantObject {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub tool_resources: Option<ToolResource>,
     pub metadata: Option<HashMap<String, String>>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone)]
@@ -101,14 +100,12 @@ pub struct DeletionStatus {
     pub id: String,
     pub object: String,
     pub deleted: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
 pub struct ListAssistant {
     pub object: String,
     pub data: Vec<AssistantObject>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize, Clone)]
@@ -122,12 +119,10 @@ pub struct AssistantFileObject {
     pub object: String,
     pub created_at: i64,
     pub assistant_id: String,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
 pub struct ListAssistantFile {
     pub object: String,
     pub data: Vec<AssistantFileObject>,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/audio.rs b/src/v1/audio.rs
index 130a042..4ab93f4 100644
--- a/src/v1/audio.rs
+++ b/src/v1/audio.rs
@@ -1,6 +1,5 @@
 use reqwest::header::HeaderMap;
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 
 use crate::impl_builder_methods;
 
@@ -59,7 +58,6 @@ impl_builder_methods!(
 #[derive(Debug, Deserialize, Serialize)]
 pub struct AudioTranscriptionResponse {
     pub text: String,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize, Clone)]
@@ -96,7 +94,6 @@ impl_builder_methods!(
 #[derive(Debug, Deserialize, Serialize)]
 pub struct AudioTranslationResponse {
     pub text: String,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 pub const TTS_1: &str = "tts-1";
diff --git a/src/v1/chat_completion.rs b/src/v1/chat_completion.rs
index 82f693b..71a884a 100644
--- a/src/v1/chat_completion.rs
+++ b/src/v1/chat_completion.rs
@@ -250,7 +250,6 @@ pub struct ChatCompletionResponse {
     pub choices: Vec<ChatCompletionChoice>,
     pub usage: common::Usage,
     pub system_fingerprint: Option<String>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
diff --git a/src/v1/completion.rs b/src/v1/completion.rs
index c4d347f..a5adeaf 100644
--- a/src/v1/completion.rs
+++ b/src/v1/completion.rs
@@ -117,5 +117,4 @@ pub struct CompletionResponse {
     pub model: String,
     pub choices: Vec<CompletionChoice>,
     pub usage: common::Usage,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/edit.rs b/src/v1/edit.rs
index c47ab01..18cf383 100644
--- a/src/v1/edit.rs
+++ b/src/v1/edit.rs
@@ -1,5 +1,4 @@
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 use std::option::Option;
 
 use crate::impl_builder_methods;
@@ -52,5 +51,4 @@ pub struct EditResponse {
     pub created: i64,
     pub usage: common::Usage,
     pub choices: Vec<EditChoice>,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/embedding.rs b/src/v1/embedding.rs
index a7305b0..3f68054 100644
--- a/src/v1/embedding.rs
+++ b/src/v1/embedding.rs
@@ -1,5 +1,4 @@
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 use std::option::Option;
 
 use crate::impl_builder_methods;
@@ -52,7 +51,6 @@ pub struct EmbeddingResponse {
     pub data: Vec<EmbeddingData>,
     pub model: String,
     pub usage: Usage,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
diff --git a/src/v1/file.rs b/src/v1/file.rs
index d475a31..fceb4f8 100644
--- a/src/v1/file.rs
+++ b/src/v1/file.rs
@@ -1,5 +1,3 @@
-use std::collections::HashMap;
-
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -16,7 +14,6 @@ pub struct FileData {
 pub struct FileListResponse {
     pub object: String,
     pub data: Vec<FileData>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize)]
@@ -39,7 +36,6 @@ pub struct FileUploadResponse {
     pub created_at: i64,
     pub filename: String,
     pub purpose: String,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize)]
@@ -58,7 +54,6 @@ pub struct FileDeleteResponse {
     pub id: String,
     pub object: String,
     pub delete: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -69,5 +64,4 @@ pub struct FileRetrieveResponse {
     pub created_at: i64,
     pub filename: String,
     pub purpose: String,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/fine_tuning.rs b/src/v1/fine_tuning.rs
index 8408a9d..8d696f9 100644
--- a/src/v1/fine_tuning.rs
+++ b/src/v1/fine_tuning.rs
@@ -1,5 +1,4 @@
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 
 use crate::impl_builder_methods;
 
@@ -99,7 +98,6 @@ pub struct FineTuningPagination<T> {
     pub object: String,
     pub data: Vec<T>,
     pub has_more: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -118,7 +116,6 @@ pub struct FineTuningJobObject {
     pub trained_tokens: Option<i64>,
     pub training_file: String,
     pub validation_file: Option<String>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
diff --git a/src/v1/image.rs b/src/v1/image.rs
index 1963146..37038b0 100644
--- a/src/v1/image.rs
+++ b/src/v1/image.rs
@@ -1,5 +1,4 @@
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 use std::option::Option;
 
 use crate::impl_builder_methods;
@@ -50,7 +49,6 @@ impl_builder_methods!(
 pub struct ImageGenerationResponse {
     pub created: i64,
     pub data: Vec<ImageData>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize, Clone)]
@@ -100,7 +98,6 @@ impl_builder_methods!(
 pub struct ImageEditResponse {
     pub created: i64,
     pub data: Vec<ImageData>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize, Clone)]
@@ -144,5 +141,4 @@ impl_builder_methods!(
 pub struct ImageVariationResponse {
     pub created: i64,
     pub data: Vec<ImageData>,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/message.rs b/src/v1/message.rs
index 094689c..8ac7b66 100644
--- a/src/v1/message.rs
+++ b/src/v1/message.rs
@@ -68,7 +68,6 @@ pub struct MessageObject {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub attachments: Option<Vec<Attachment>>,
     pub metadata: Option<HashMap<String, String>>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone)]
@@ -111,7 +110,6 @@ pub struct ListMessage {
     pub first_id: String,
     pub last_id: String,
     pub has_more: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -120,7 +118,6 @@ pub struct MessageFileObject {
     pub object: String,
     pub created_at: i64,
     pub message_id: String,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -130,7 +127,6 @@ pub struct ListMessageFile {
     pub first_id: String,
     pub last_id: String,
     pub has_more: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
diff --git a/src/v1/moderation.rs b/src/v1/moderation.rs
index b4989eb..69acece 100644
--- a/src/v1/moderation.rs
+++ b/src/v1/moderation.rs
@@ -1,5 +1,4 @@
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 
 use crate::impl_builder_methods;
 
@@ -26,7 +25,6 @@ pub struct CreateModerationResponse {
     pub id: String,
     pub model: String,
     pub results: Vec<ModerationResult>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
diff --git a/src/v1/run.rs b/src/v1/run.rs
index 645104f..d084b62 100644
--- a/src/v1/run.rs
+++ b/src/v1/run.rs
@@ -98,7 +98,6 @@ pub struct RunObject {
     pub instructions: Option<String>,
     pub tools: Vec<types::Tools>,
     pub metadata: HashMap<String, String>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -108,7 +107,6 @@ pub struct ListRun {
     pub first_id: String,
     pub last_id: String,
     pub has_more: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Serialize, Clone)]
@@ -151,7 +149,6 @@ pub struct RunStepObject {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub completed_at: Option<i64>,
     pub metadata: HashMap<String, String>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone)]
@@ -161,5 +158,4 @@ pub struct ListRunStep {
     pub first_id: String,
     pub last_id: String,
     pub has_more: bool,
-    pub headers: Option<HashMap<String, String>>,
 }
diff --git a/src/v1/thread.rs b/src/v1/thread.rs
index 57e0b5c..73b1f5c 100644
--- a/src/v1/thread.rs
+++ b/src/v1/thread.rs
@@ -67,8 +67,6 @@ pub struct ThreadObject {
     pub metadata: HashMap<String, String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub tool_resources: Option<ToolResource>,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone)]
@@ -86,7 +84,6 @@ pub struct Message {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub attachments: Option<Vec<Attachment>>,
     pub metadata: Option<HashMap<String, String>>,
-    pub headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone)]