diff --git a/backend/open_webui/routers/openai.py b/backend/open_webui/routers/openai.py
index 44575e57f2..b1d31afb8f 100644
--- a/backend/open_webui/routers/openai.py
+++ b/backend/open_webui/routers/openai.py
@@ -794,6 +794,79 @@ def convert_to_azure_payload(url, payload: dict, api_version: str):
     return url, payload
 
 
+def convert_to_responses_payload(payload: dict) -> dict:
+    """
+    Convert Chat Completions payload to Responses API format.
+    
+    Chat Completions: { messages: [{role, content}], ... }
+    Responses API: { input: [{type: "message", role, content: [...]}], instructions: "system" }
+    """
+    messages = payload.pop("messages", [])
+    
+    system_content = ""
+    input_items = []
+    
+    for msg in messages:
+        role = msg.get("role", "user")
+        content = msg.get("content", "")
+        
+        # Check for stored output items (from previous Responses API turn)
+        stored_output = msg.get("output")
+        if stored_output and isinstance(stored_output, list):
+            input_items.extend(stored_output)
+            continue
+        
+        if role == "system":
+            if isinstance(content, str):
+                system_content = content
+            elif isinstance(content, list):
+                system_content = "\n".join(p.get("text", "") for p in content if p.get("type") == "text")
+            continue
+        
+        # Convert content format
+        text_type = "output_text" if role == "assistant" else "input_text"
+        
+        if isinstance(content, str):
+            content_parts = [{"type": text_type, "text": content}]
+        elif isinstance(content, list):
+            content_parts = []
+            for part in content:
+                if part.get("type") == "text":
+                    content_parts.append({"type": text_type, "text": part.get("text", "")})
+                elif part.get("type") == "image_url":
+                    url_data = part.get("image_url", {})
+                    url = url_data.get("url", "") if isinstance(url_data, dict) else url_data
+                    content_parts.append({"type": "input_image", "image_url": url})
+        else:
+            content_parts = [{"type": text_type, "text": str(content)}]
+        
+        input_items.append({
+            "type": "message",
+            "role": role,
+            "content": content_parts
+        })
+    
+    responses_payload = {**payload, "input": input_items}
+    
+    if system_content:
+        responses_payload["instructions"] = system_content
+    
+    if "max_tokens" in responses_payload:
+        responses_payload["max_output_tokens"] = responses_payload.pop("max_tokens")
+    
+    return responses_payload
+
+
+
+def convert_responses_result(response: dict) -> dict:
+    """
+    Convert non-streaming Responses API result.
+    Just add done flag - pass through raw response, frontend handles output.
+    """
+    response["done"] = True
+    return response
+
+
 @router.post("/chat/completions")
 async def generate_chat_completion(
     request: Request,
@@ -915,6 +988,8 @@ async def generate_chat_completion(
         request, url, key, api_config, metadata, user=user
     )
 
+    is_responses = api_config.get("api_type") == "responses"
+
     if api_config.get("azure", False):
         api_version = api_config.get("api_version", "2023-03-15-preview")
         request_url, payload = convert_to_azure_payload(url, payload, api_version)
@@ -925,9 +1000,18 @@ async def generate_chat_completion(
             headers["api-key"] = key
 
         headers["api-version"] = api_version
-        request_url = f"{request_url}/chat/completions?api-version={api_version}"
+        
+        if is_responses:
+            payload = convert_to_responses_payload(payload)
+            request_url = f"{request_url}/responses?api-version={api_version}"
+        else:
+            request_url = f"{request_url}/chat/completions?api-version={api_version}"
     else:
-        request_url = f"{url}/chat/completions"
+        if is_responses:
+            payload = convert_to_responses_payload(payload)
+            request_url = f"{url}/responses"
+        else:
+            request_url = f"{url}/chat/completions"
 
     payload = json.dumps(payload)
 
@@ -974,6 +1058,10 @@ async def generate_chat_completion(
                 else:
                     return PlainTextResponse(status_code=r.status, content=response)
 
+            # Convert Responses API result to simple format
+            if is_responses and isinstance(response, dict):
+                response = convert_responses_result(response)
+
             return response
     except Exception as e:
         log.exception(e)
diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index cf0f145012..0f40ce5941 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -294,6 +294,476 @@ def get_citation_source_from_tool_result(
         ]
 
 
+def split_content_and_whitespace(content):
+    content_stripped = content.rstrip()
+    original_whitespace = (
+        content[len(content_stripped) :] if len(content) > len(content_stripped) else ""
+    )
+    return content_stripped, original_whitespace
+
+
+def is_opening_code_block(content):
+    backtick_segments = content.split("```")
+    # Even number of segments means the last backticks are opening a new block
+    return len(backtick_segments) > 1 and len(backtick_segments) % 2 == 0
+
+
+def serialize_output(output: list) -> str:
+    """
+    Convert OR-aligned output items to HTML for display.
+    For LLM consumption, use convert_output_to_messages() instead.
+    """
+    content = ""
+
+    # First pass: collect function_call_output items by call_id for lookup
+    tool_outputs = {}
+    for item in output:
+        if item.get("type") == "function_call_output":
+            tool_outputs[item.get("call_id")] = item
+
+    # Second pass: render items in order
+    for idx, item in enumerate(output):
+        item_type = item.get("type", "")
+
+        if item_type == "message":
+            for content_part in item.get("content", []):
+                if "text" in content_part:
+                    text = content_part.get("text", "").strip()
+                    if text:
+                        content = f"{content}{text}\n"
+
+        elif item_type == "function_call":
+            # Render tool call inline with its result (if available)
+            if content and not content.endswith("\n"):
+                content += "\n"
+
+            call_id = item.get("call_id", "")
+            name = item.get("name", "")
+            arguments = item.get("arguments", "")
+
+            result_item = tool_outputs.get(call_id)
+            if result_item:
+                result_text = ""
+                for out in result_item.get("output", []):
+                    if "text" in out:
+                        result_text += out.get("text", "")
+                files = result_item.get("files")
+                embeds = result_item.get("embeds", "")
+
+                content += f'<details type="tool_calls" done="true" id="{call_id}" name="{name}" arguments="{html.escape(json.dumps(arguments))}" result="{html.escape(json.dumps(result_text, ensure_ascii=False))}" files="{html.escape(json.dumps(files)) if files else ""}" embeds="{html.escape(json.dumps(embeds))}">\n<summary>Tool Executed</summary>\n</details>\n'
+            else:
+                content += f'<details type="tool_calls" done="false" id="{call_id}" name="{name}" arguments="{html.escape(json.dumps(arguments))}">\n<summary>Executing...</summary>\n</details>\n'
+
+        elif item_type == "function_call_output":
+            # Already handled inline with function_call above
+            pass
+
+        elif item_type == "reasoning":
+            reasoning_content = ""
+            # Check for 'summary' (new structure) or 'content' (legacy/fallback)
+            source_list = item.get("summary", []) or item.get("content", [])
+            for content_part in source_list:
+                if "text" in content_part:
+                    reasoning_content += content_part.get("text", "")
+                elif "summary" in content_part:  # Handle potential nested logic if any
+                    pass
+
+            reasoning_content = reasoning_content.strip()
+
+            duration = item.get("duration")
+            status = item.get("status", "in_progress")
+
+            # Infer completion: if this reasoning item is NOT the last item,
+            # render as done (a subsequent item means reasoning is complete)
+            is_last_item = idx == len(output) - 1
+
+            if content and not content.endswith("\n"):
+                content += "\n"
+
+            display = html.escape(
+                "\n".join(
+                    (f"> {line}" if not line.startswith(">") else line)
+                    for line in reasoning_content.splitlines()
+                )
+            )
+
+            if status == "completed" or duration is not None or not is_last_item:
+                content = f'{content}<details type="reasoning" done="true" duration="{duration or 0}">\n<summary>Thought for {duration or 0} seconds</summary>\n{display}\n</details>\n'
+            else:
+                content = f'{content}<details type="reasoning" done="false">\n<summary>Thinking…</summary>\n{display}\n</details>\n'
+
+        elif item_type == "open_webui:code_interpreter":
+            content_stripped, original_whitespace = split_content_and_whitespace(
+                content
+            )
+            if is_opening_code_block(content_stripped):
+                content = content_stripped.rstrip("`").rstrip() + original_whitespace
+            else:
+                content = content_stripped + original_whitespace
+
+            if content and not content.endswith("\n"):
+                content += "\n"
+
+    return content.strip()
+
+
+def deep_merge(target, source):
+    """
+    Merge source into target recursively (returning new structure).
+    - Dicts: Recursive merge.
+    - Strings: Concatenation.
+    - Others: Overwrite.
+    """
+    if isinstance(target, dict) and isinstance(source, dict):
+        new_target = target.copy()
+        for k, v in source.items():
+            if k in new_target:
+                new_target[k] = deep_merge(new_target[k], v)
+            else:
+                new_target[k] = v
+        return new_target
+    elif isinstance(target, str) and isinstance(source, str):
+        return target + source
+    else:
+        return source
+
+
+def handle_responses_streaming_event(
+    data: dict,
+    current_output: list,
+) -> tuple[list, dict | None]:
+    """
+    Handle Responses API streaming events in a pure functional way.
+
+    Args:
+        data: The event data
+        current_output: List of output items (treated as immutable)
+
+    Returns:
+        tuple[list, dict | None]: (new_output, metadata)
+        - new_output: The updated output list.
+        - metadata: Metadata to emit (e.g. usage), {} if update occurred, None if skip.
+    """
+    # Default: no change
+    # Note: treating current_output as immutable, but avoiding full deepcopy for perf.
+    # We will shallow copy only if we need to modify the list structure or items.
+
+    event_type = data.get("type", "")
+
+    if event_type == "response.output_item.added":
+        item = data.get("item", {})
+        if item:
+            new_output = list(current_output)
+            new_output.append(item)
+            return new_output, None
+        return current_output, None
+
+    elif event_type == "response.content_part.added":
+        part = data.get("part", {})
+        output_index = data.get("output_index", len(current_output) - 1)
+
+        if current_output and 0 <= output_index < len(current_output):
+            new_output = list(current_output)
+            # Copy the item to mutate it
+            item = new_output[output_index].copy()
+            new_output[output_index] = item
+
+            if "content" not in item:
+                item["content"] = []
+            else:
+                # Copy content list
+                item["content"] = list(item["content"])
+
+            if item.get("type") == "reasoning":
+                # Reasoning items should not have content parts
+                pass
+            else:
+                item["content"].append(part)
+                item["content"].append(part)
+            return new_output, None
+        return current_output, None
+
+    elif event_type == "response.reasoning_summary_part.added":
+        part = data.get("part", {})
+        output_index = data.get("output_index", len(current_output) - 1)
+
+        if current_output and 0 <= output_index < len(current_output):
+            new_output = list(current_output)
+            item = new_output[output_index].copy()
+            new_output[output_index] = item
+
+            if "summary" not in item:
+                item["summary"] = []
+            else:
+                item["summary"] = list(item["summary"])
+
+            item["summary"].append(part)
+            return new_output, None
+        return current_output, None
+
+    elif event_type.startswith("response.") and event_type.endswith(".delta"):
+        # Generic Delta Handling
+        parts = event_type.split(".")
+        if len(parts) >= 3:
+            delta_type = parts[1]
+            delta = data.get("delta", "")
+
+            output_index = data.get("output_index", len(current_output) - 1)
+
+            if current_output and 0 <= output_index < len(current_output):
+                new_output = list(current_output)
+                item = new_output[output_index].copy()
+                new_output[output_index] = item
+                item_type = item.get("type", "")
+
+                # Determine target field and object based on delta_type and item_type
+                if delta_type == "function_call_arguments":
+                    key = "arguments"
+                    if item_type == "function_call":
+                        # Function call args are usually strings
+                        item[key] = item.get(key, "") + str(delta)
+                else:
+                    # Generic handling, refined by item type below
+                    pass
+
+                    if item_type == "message":
+                        # Message items: "text"/"output_text" -> "text"
+                        # "reasoning_text" -> Skipped (should use reasoning item)
+                        if delta_type in ["text", "output_text"]:
+                            key = "text"
+                        elif delta_type in ["reasoning_text", "reasoning_summary_text"]:
+                            # Skip reasoning updates for message items
+                            return new_output, None
+                        else:
+                            key = delta_type
+
+                        content_index = data.get("content_index", 0)
+                        if "content" not in item:
+                            item["content"] = []
+                        else:
+                            item["content"] = list(item["content"])
+                        content_list = item["content"]
+
+                        while len(content_list) <= content_index:
+                            content_list.append({"type": "text", "text": ""})
+
+                        # Copy the part to mutate it
+                        part = content_list[content_index].copy()
+                        content_list[content_index] = part
+
+                        current_val = part.get(key)
+                        if current_val is None:
+                            # Initialize based on delta type
+                            current_val = {} if isinstance(delta, dict) else ""
+
+                        part[key] = deep_merge(current_val, delta)
+
+                    elif item_type == "reasoning":
+                        # Reasoning items: "reasoning_text"/"reasoning_summary_text" -> "text"
+                        # "text"/"output_text" -> Skipped (should use message item)
+                        if delta_type == "reasoning_summary_text":
+                            # Summary updates -> item['summary']
+                            key = "text"
+                            summary_index = data.get("summary_index", 0)
+                            if "summary" not in item:
+                                item["summary"] = []
+                            else:
+                                item["summary"] = list(item["summary"])
+                            summary_list = item["summary"]
+
+                            while len(summary_list) <= summary_index:
+                                summary_list.append(
+                                    {"type": "summary_text", "text": ""}
+                                )
+
+                            part = summary_list[summary_index].copy()
+                            summary_list[summary_index] = part
+
+                            target_val = part.get(key, "")
+                            part[key] = deep_merge(target_val, delta)
+
+                        elif delta_type == "reasoning_text":
+                            # Reasoning body updates -> item['content']
+                            key = "text"
+                            content_index = data.get("content_index", 0)
+                            if "content" not in item:
+                                item["content"] = []
+                            else:
+                                item["content"] = list(item["content"])
+                            content_list = item["content"]
+
+                            while len(content_list) <= content_index:
+                                # Reasoning content parts default to text
+                                content_list.append({"type": "text", "text": ""})
+
+                            part = content_list[content_index].copy()
+                            content_list[content_index] = part
+
+                            target_val = part.get(key, "")
+                            part[key] = deep_merge(target_val, delta)
+
+                        elif delta_type in ["text", "output_text"]:
+                            return new_output, None
+                        else:
+                            # Fallback just in case other deltas target reasoning?
+                            pass
+
+                    else:
+                        # Fallback for other item types
+                        if delta_type in ["text", "output_text"]:
+                            key = "text"
+                        else:
+                            key = delta_type
+
+                        current_val = item.get(key)
+                        if current_val is None:
+                            current_val = {} if isinstance(delta, dict) else ""
+                        item[key] = deep_merge(current_val, delta)
+
+            return new_output, None
+
+    elif event_type.startswith("response.") and event_type.endswith(".done"):
+        # Delta Events: response.content_part.done, response.text.done, etc.
+        parts = event_type.split(".")
+        if len(parts) >= 3:
+            type_name = parts[1]
+
+            # 1. Handle specific Delta "done" signals
+            if type_name == "content_part":
+                # "Signaling that no further changes will occur to a content part"
+                # If payloads contains the full part, we could update it.
+                # Usually purely signaling in standard implementation, but we check payload.
+                part = data.get("part")
+                output_index = data.get("output_index", len(current_output) - 1)
+
+                if part and current_output and 0 <= output_index < len(current_output):
+                    new_output = list(current_output)
+                    item = new_output[output_index].copy()
+                    new_output[output_index] = item
+
+                    if "content" in item:
+                        item["content"] = list(item["content"])
+                        content_index = data.get(
+                            "content_index", len(item["content"]) - 1
+                        )
+                        if 0 <= content_index < len(item["content"]):
+                            item["content"][content_index] = part
+                            return new_output, {}
+                return current_output, None
+
+            elif type_name == "reasoning_summary_part":
+                part = data.get("part")
+                output_index = data.get("output_index", len(current_output) - 1)
+
+                if part and current_output and 0 <= output_index < len(current_output):
+                    new_output = list(current_output)
+                    item = new_output[output_index].copy()
+                    new_output[output_index] = item
+
+                    if "summary" in item:
+                        item["summary"] = list(item["summary"])
+                        summary_index = data.get(
+                            "summary_index", len(item["summary"]) - 1
+                        )
+                        if 0 <= summary_index < len(item["summary"]):
+                            item["summary"][summary_index] = part
+                            return new_output, {}
+                return current_output, None
+
+            # 2. Skip Output Item done (handled specifically below)
+            if type_name == "output_item":
+                pass
+
+            # 3. Generic Field Done (text.done, audio.done)
+            elif type_name not in ["completed", "failed"]:
+                output_index = data.get("output_index", len(current_output) - 1)
+                if current_output and 0 <= output_index < len(current_output):
+
+                    key = (
+                        "text"
+                        if type_name
+                        in [
+                            "text",
+                            "output_text",
+                            "reasoning_text",
+                            "reasoning_summary_text",
+                        ]
+                        else type_name
+                    )
+                    if type_name == "function_call_arguments":
+                        key = "arguments"
+
+                    if key in data:
+                        final_value = data[key]
+                        new_output = list(current_output)
+                        item = new_output[output_index].copy()
+                        new_output[output_index] = item
+                        item_type = item.get("type", "")
+
+                        if type_name == "function_call_arguments":
+                            if item_type == "function_call":
+                                item["arguments"] = final_value
+                        elif item_type == "message":
+                            content_index = data.get("content_index", 0)
+                            if "content" in item:
+                                item["content"] = list(item["content"])
+                                if len(item["content"]) > content_index:
+                                    part = item["content"][content_index].copy()
+                                    item["content"][content_index] = part
+                                    part[key] = final_value
+                        elif item_type == "reasoning":
+                            item["status"] = "completed"
+                        else:
+                            item[key] = final_value
+
+                        return new_output, {}
+
+        return current_output, None
+
+    elif event_type == "response.output_item.done":
+        # Delta Event: Output item complete
+        item = data.get("item")
+        output_index = data.get("output_index", len(current_output) - 1)
+
+        new_output = list(current_output)
+        if item and 0 <= output_index < len(current_output):
+            new_output[output_index] = item
+        elif item:
+            new_output.append(item)
+        return new_output, {}
+
+    elif event_type == "response.completed":
+        # State Machine Event: Completed
+        response_data = data.get("response", {})
+        final_output = response_data.get("output")
+
+        new_output = final_output if final_output is not None else current_output
+
+        # Ensure reasoning items are marked as completed in the final output
+        if new_output:
+            for item in new_output:
+                if (
+                    item.get("type") == "reasoning"
+                    and item.get("status") != "completed"
+                ):
+                    item["status"] = "completed"
+
+        return new_output, {"usage": response_data.get("usage"), "done": True}
+
+    elif event_type == "response.in_progress":
+        # State Machine Event: In Progress
+        # We could extract metadata if needed, but for now just acknowledge iteration
+        return current_output, None
+
+    elif event_type == "response.failed":
+        # State Machine Event: Failed
+        error = data.get("response", {}).get("error", {})
+        return current_output, {"error": error}
+
+    else:
+        return current_output, None
+
+
 def apply_source_context_to_messages(
     request: Request,
     messages: list,
@@ -1571,7 +2041,9 @@ async def process_chat_payload(request, form_data, user, metadata, model):
         raise e
 
     try:
-        filter_ids = get_sorted_filter_ids(request, model, metadata.get("filter_ids", []))
+        filter_ids = get_sorted_filter_ids(
+            request, model, metadata.get("filter_ids", [])
+        )
         filter_functions = Functions.get_functions_by_ids(filter_ids)
 
         form_data, flags = await process_filter_functions(
@@ -2368,20 +2840,6 @@ async def process_chat_response(
         task_id = str(uuid4())  # Create a unique task ID.
         model_id = form_data.get("model", "")
 
-        def split_content_and_whitespace(content):
-            content_stripped = content.rstrip()
-            original_whitespace = (
-                content[len(content_stripped) :]
-                if len(content) > len(content_stripped)
-                else ""
-            )
-            return content_stripped, original_whitespace
-
-        def is_opening_code_block(content):
-            backtick_segments = content.split("```")
-            # Even number of segments means the last backticks are opening a new block
-            return len(backtick_segments) > 1 and len(backtick_segments) % 2 == 0
-
         # Handle as a background task
         async def response_handler(response, events):
             def serialize_content_blocks(content_blocks, raw=False):
@@ -2519,105 +2977,6 @@ async def process_chat_response(
 
                 return content.strip()
 
-            def serialize_output(output: list) -> str:
-                """
-                Convert OR-aligned output items to HTML for display.
-                For LLM consumption, use convert_output_to_messages() instead.
-                """
-                content = ""
-
-                # First pass: collect function_call_output items by call_id for lookup
-                tool_outputs = {}
-                for item in output:
-                    if item.get("type") == "function_call_output":
-                        tool_outputs[item.get("call_id")] = item
-
-                # Second pass: render items in order
-                for item in output:
-                    item_type = item.get("type", "")
-
-                    if item_type == "message":
-                        for content_part in item.get("content", []):
-                            if content_part.get("type") == "output_text":
-                                text = content_part.get("text", "").strip()
-                                if text:
-                                    content = f"{content}{text}\n"
-
-                    elif item_type == "function_call":
-                        # Render tool call inline with its result (if available)
-                        if content and not content.endswith("\n"):
-                            content += "\n"
-
-                        call_id = item.get("call_id", "")
-                        name = item.get("name", "")
-                        arguments = item.get("arguments", "")
-
-                        result_item = tool_outputs.get(call_id)
-                        if result_item:
-                            result_text = ""
-                            for out in result_item.get("output", []):
-                                if out.get("type") == "input_text":
-                                    result_text += out.get("text", "")
-                            files = result_item.get("files")
-                            embeds = result_item.get("embeds", "")
-
-                            content += f'<details type="tool_calls" done="true" id="{call_id}" name="{name}" arguments="{html.escape(json.dumps(arguments))}" result="{html.escape(json.dumps(result_text, ensure_ascii=False))}" files="{html.escape(json.dumps(files)) if files else ""}" embeds="{html.escape(json.dumps(embeds))}">\n<summary>Tool Executed</summary>\n</details>\n'
-                        else:
-                            content += f'<details type="tool_calls" done="false" id="{call_id}" name="{name}" arguments="{html.escape(json.dumps(arguments))}">\n<summary>Executing...</summary>\n</details>\n'
-
-                    elif item_type == "function_call_output":
-                        # Already handled inline with function_call above
-                        pass
-
-                    elif item_type == "reasoning":
-                        reasoning_content = ""
-                        for content_part in item.get("content", []):
-                            if content_part.get("type") == "output_text":
-                                reasoning_content = content_part.get("text", "").strip()
-
-                        duration = item.get("duration")
-                        status = item.get("status", "in_progress")
-
-                        if content and not content.endswith("\n"):
-                            content += "\n"
-
-                        display = html.escape(
-                            "\n".join(
-                                (f"> {line}" if not line.startswith(">") else line)
-                                for line in reasoning_content.splitlines()
-                            )
-                        )
-
-                        if status == "completed" or duration is not None:
-                            content = f'{content}<details type="reasoning" done="true" duration="{duration or 0}">\n<summary>Thought for {duration or 0} seconds</summary>\n{display}\n</details>\n'
-                        else:
-                            content = f'{content}<details type="reasoning" done="false">\n<summary>Thinking…</summary>\n{display}\n</details>\n'
-
-                    elif item_type == "open_webui:code_interpreter":
-                        code = item.get("code", "")
-                        output_val = item.get("output")
-                        lang = item.get("lang", "")
-
-                        content_stripped, original_whitespace = (
-                            split_content_and_whitespace(content)
-                        )
-                        if is_opening_code_block(content_stripped):
-                            content = (
-                                content_stripped.rstrip("`").rstrip()
-                                + original_whitespace
-                            )
-                        else:
-                            content = content_stripped + original_whitespace
-
-                        if content and not content.endswith("\n"):
-                            content += "\n"
-
-                        if output_val:
-                            output_escaped = html.escape(json.dumps(output_val))
-                            content = f'{content}<details type="code_interpreter" done="true" output="{output_escaped}">\n<summary>Analyzed</summary>\n```{lang}\n{code}\n```\n</details>\n'
-                        else:
-                            content = f'{content}<details type="code_interpreter" done="false">\n<summary>Analyzing...</summary>\n```{lang}\n{code}\n```\n</details>\n'
-
                 return content.strip()
 
             def convert_content_blocks_to_messages(content_blocks, raw=False):
@@ -2983,16 +3342,19 @@ async def process_chat_response(
             if existing_output:
                 output = existing_output
             else:
-                # Always create an initial message item (even if content is empty)
-                output = [
-                    {
-                        "type": "message",
-                        "id": output_id("msg"),
-                        "status": "in_progress",
-                        "role": "assistant",
-                        "content": [{"type": "output_text", "text": content}],
-                    }
-                ]
+                # Only create an initial message item if there is content to initialize with
+                if content:
+                    output = [
+                        {
+                            "type": "message",
+                            "id": output_id("msg"),
+                            "status": "in_progress",
+                            "role": "assistant",
+                            "content": [{"type": "output_text", "text": content}],
+                        }
+                    ]
+                else:
+                    output = []
 
             # Keep content_blocks for backward compatibility during transition
             content_blocks = [
@@ -3043,6 +3405,7 @@ async def process_chat_response(
                     nonlocal content
                     nonlocal content_blocks
                     nonlocal usage
+                    nonlocal output
 
                     response_tool_calls = []
 
@@ -3121,6 +3484,31 @@ async def process_chat_response(
                                             "data": data,
                                         }
                                     )
+                                # Check for Responses API events (type field starts with "response.")
+                                elif data.get("type", "").startswith("response."):
+                                    output, response_metadata = (
+                                        handle_responses_streaming_event(data, output)
+                                    )
+
+                                    processed_data = {
+                                        "output": output,
+                                        "content": serialize_output(output),
+                                    }
+
+                                    # print(data)
+                                    # print(processed_data)
+
+                                    # Merge any metadata (usage, done, etc.)
+                                    if response_metadata:
+                                        processed_data.update(response_metadata)
+
+                                    await event_emitter(
+                                        {
+                                            "type": "chat:completion",
+                                            "data": processed_data,
+                                        }
+                                    )
+                                    continue
                                 else:
                                     choices = data.get("choices", [])
 
diff --git a/pyproject.toml b/pyproject.toml
index 1f46eaa068..3f07770850 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ dependencies = [
     "authlib==1.6.6",
 
     "requests==2.32.5",
-    "aiohttp==3.13.2" # do not update to 3.13.3 - broken,
+    "aiohttp==3.13.2", # do not update to 3.13.3 - broken
     "async-timeout",
     "aiocache",
     "aiofiles",
diff --git a/src/lib/components/AddConnectionModal.svelte b/src/lib/components/AddConnectionModal.svelte
index 557549098c..a455627e11 100644
--- a/src/lib/components/AddConnectionModal.svelte
+++ b/src/lib/components/AddConnectionModal.svelte
@@ -42,6 +42,7 @@
 	let prefixId = '';
 	let enable = true;
 	let apiVersion = '';
+	let apiType = ''; // '' = chat completions (default), 'responses' = Responses API
 
 	let headers = '';
 
@@ -183,7 +184,8 @@
 				connection_type: connectionType,
 				auth_type,
 				headers: headers ? JSON.parse(headers) : undefined,
-				...(!ollama && azure ? { azure: true, api_version: apiVersion } : {})
+				...(!ollama && azure ? { azure: true, api_version: apiVersion } : {}),
+				...(apiType ? { api_type: apiType } : {})
 			}
 		};
 
@@ -221,6 +223,7 @@
 				connectionType = connection.config?.connection_type ?? 'external';
 				azure = connection.config?.azure ?? false;
 				apiVersion = connection.config?.api_version ?? '';
+				apiType = connection.config?.api_type ?? '';
 			}
 		}
 	};
@@ -506,7 +509,7 @@
 									<div class="flex-1">
 										<input
 											id="api-version-input"
-											class={`w-full text-sm bg-transparent placeholder:text-gray-300 dark:placeholder:text-gray-700 ${($settings?.highContrastMode ?? false) ? 'placeholder:text-gray-700 dark:placeholder:text-gray-100' : 'outline-hidden placeholder:text-gray-300 dark:placeholder:text-gray-700'}`}
+											class={`w-full text-sm bg-transparent ${($settings?.highContrastMode ?? false) ? 'placeholder:text-gray-700 dark:placeholder:text-gray-100' : 'outline-hidden placeholder:text-gray-300 dark:placeholder:text-gray-700'}`}
 											type="text"
 											bind:value={apiVersion}
 											placeholder={$i18n.t('API Version')}
@@ -518,6 +521,45 @@
 							</div>
 						{/if}
 
+						{#if !ollama && !direct}
+							<div class="flex flex-row justify-between items-center w-full mt-1">
+								<label
+									for="api-type-toggle"
+									class={`mb-0.5 text-xs text-gray-500
+							${($settings?.highContrastMode ?? false) ? 'text-gray-800 dark:text-gray-100' : ''}`}
+									>{$i18n.t('API Type')}</label
+								>
+
+								<div>
+									<button
+										on:click={() => {
+											apiType = apiType === 'responses' ? '' : 'responses';
+										}}
+										type="button"
+										id="api-type-toggle"
+										class=" text-xs text-gray-700 dark:text-gray-300"
+									>
+										{#if apiType === 'responses'}
+											<Tooltip
+												className="flex items-center gap-1"
+												content={$i18n.t(
+													'This feature is currently experimental and may not work as expected.'
+												)}
+											>
+												<span class=" text-gray-400 dark:text-gray-600"
+													>{$i18n.t('Experimental')}</span
+												>
+
+												{$i18n.t('Responses')}
+											</Tooltip>
+										{:else}
+											{$i18n.t('Chat Completions')}
+										{/if}
+									</button>
+								</div>
+							</div>
+						{/if}
+
 						<div class="flex flex-col w-full mt-2">
 							<div class="mb-1 flex justify-between">
 								<div
diff --git a/src/lib/components/chat/Messages/Markdown/MarkdownTokens.svelte b/src/lib/components/chat/Messages/Markdown/MarkdownTokens.svelte
index d22cd2e7dc..dcb403e279 100644
--- a/src/lib/components/chat/Messages/Markdown/MarkdownTokens.svelte
+++ b/src/lib/components/chat/Messages/Markdown/MarkdownTokens.svelte
@@ -54,7 +54,9 @@
 		console.log('Exporting table to CSV');
 
 		// Extract header row text, decode HTML entities, and escape for CSV.
-		const header = token.header.map((headerCell) => `"${decode(headerCell.text).replace(/"/g, '""')}"`);
+		const header = token.header.map(
+			(headerCell) => `"${decode(headerCell.text).replace(/"/g, '""')}"`
+		);
 
 		// Create an array for rows that will hold the mapped cell text.
 		const rows = token.rows.map((row) =>
@@ -316,26 +318,41 @@
 			</ul>
 		{/if}
 	{:else if token.type === 'details'}
-		<Collapsible
-			title={token.summary}
-			open={$settings?.expandDetails ?? false}
-			attributes={token?.attributes}
-			className="w-full space-y-1"
-			dir="auto"
-		>
-			<div class=" mb-1.5" slot="content">
-				<svelte:self
-					id={`${id}-${tokenIdx}-d`}
-					tokens={marked.lexer(decode(token.text))}
-					attributes={token?.attributes}
-					{done}
-					{editCodeBlock}
-					{onTaskClick}
-					{sourceIds}
-					{onSourceClick}
-				/>
-			</div>
-		</Collapsible>
+		{@const textContent = decode(token.text || '')
+			.replace(/<summary>.*?<\/summary>/gi, '')
+			.trim()}
+
+		{#if textContent.length > 0}
+			<Collapsible
+				title={token.summary}
+				open={$settings?.expandDetails ?? false}
+				attributes={token?.attributes}
+				className="w-full space-y-1"
+				dir="auto"
+			>
+				<div class=" mb-1.5" slot="content">
+					<svelte:self
+						id={`${id}-${tokenIdx}-d`}
+						tokens={marked.lexer(decode(token.text))}
+						attributes={token?.attributes}
+						{done}
+						{editCodeBlock}
+						{onTaskClick}
+						{sourceIds}
+						{onSourceClick}
+					/>
+				</div>
+			</Collapsible>
+		{:else}
+			<Collapsible
+				title={token.summary}
+				open={false}
+				disabled={true}
+				attributes={token?.attributes}
+				className="w-full space-y-1"
+				dir="auto"
+			/>
+		{/if}
 	{:else if token.type === 'html'}
 		<HtmlToken {id} {token} {onSourceClick} />
 	{:else if token.type === 'iframe'}
diff --git a/src/lib/components/common/Collapsible.svelte b/src/lib/components/common/Collapsible.svelte
index 69262328b8..efaa83f385 100644
--- a/src/lib/components/common/Collapsible.svelte
+++ b/src/lib/components/common/Collapsible.svelte
@@ -222,7 +222,7 @@
 			<!-- svelte-ignore a11y-no-static-element-interactions -->
 			<!-- svelte-ignore a11y-click-events-have-key-events -->
 			<div
-				class="{buttonClassName} cursor-pointer"
+				class="{buttonClassName} {disabled ? '' : 'cursor-pointer'}"
 				on:pointerup={() => {
 					if (!disabled) {
 						open = !open;
@@ -270,13 +270,15 @@
 						{/if}
 					</div>
 
-					<div class="flex self-center translate-y-[1px]">
-						{#if open}
-							<ChevronUp strokeWidth="3.5" className="size-3.5" />
-						{:else}
-							<ChevronDown strokeWidth="3.5" className="size-3.5" />
-						{/if}
-					</div>
+					{#if !disabled}
+						<div class="flex self-center translate-y-[1px]">
+							{#if open}
+								<ChevronUp strokeWidth="3.5" className="size-3.5" />
+							{:else}
+								<ChevronDown strokeWidth="3.5" className="size-3.5" />
+							{/if}
+						</div>
+					{/if}
 				</div>
 			</div>
 		{:else}