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Open Responses

Overview​

Open WebUI has experimental support for Open Responses, an open specification for multi-provider, interoperable LLM interfaces. This guide walks you through enabling the Open Responses API for a connection.

Experimental Feature

This feature is currently experimental and may not work as expected with all providers.

What is Open Responses?​

Open Responses is an open-source specification that standardizes how LLM requests and responses are structured across providers. It provides:

  • One spec, many providers: Describe inputs/outputs once; run on OpenAI, Anthropic, Gemini, or local models.
  • Composable agentic loops: Unified streaming, tool invocation, and message orchestration.
  • Easier evaluation and routing: Compare providers, route requests, and log results through a shared schema.

Open Responses builds on the OpenAI Responses API format but is designed to work across any provider that implements the spec.

Step 1: Add or Edit a Connection​

  1. Go to the ⚙ī¸ Admin Settings.
  2. Navigate to Connections > OpenAI > Manage (look for the wrench icon).
  3. Click ➕ Add New Connection or edit an existing connection.

Step 2: Select the API Type​

In the connection modal, look for the API Type setting:

  • Chat Completions (default): Uses the standard OpenAI Chat Completions API format.
  • Responses (experimental): Uses the Open Responses API format.

Click the toggle to switch to Responses. You'll see an "Experimental" label indicating this feature is still in development.

API Type Toggle

Step 3: Configure Your Provider​

Enter the connection details for a provider that supports the Open Responses format:

  • URL: Your provider's API endpoint
  • API Key: Your authentication credentials
  • Model IDs: (Optional) Specify specific models to use

Supported Providers​

Open Responses is a new specification, so provider support is still growing. Check the Open Responses website for the latest list of compliant providers and implementations.

Troubleshooting​

Connection works with Chat Completions but not Responses​

Not all providers support the Open Responses format yet. Try:

  1. Switching back to Chat Completions
  2. Checking if your provider explicitly supports Open Responses
  3. Using a middleware proxy that can translate to Open Responses format

Streaming or tool calls behave unexpectedly​

Tool calls, re-invocations, and streaming are supported for Responses API connections. Open WebUI transparently converts between Chat Completions and Responses API formats, including tool call arguments, function call outputs, and multi-turn tool use. If you still encounter issues:

  1. Check the Open WebUI Discord for known issues
  2. Report bugs on GitHub

Stateful sessions​

By default, Open WebUI treats Responses API connections as stateless — it manages conversation history locally and sends the full context with each request. If your upstream provider supports stateful sessions (server-side response storage with previous_response_id anchoring, e.g., direct OpenAI connections), you can enable ENABLE_RESPONSES_API_STATEFUL=true to let the provider manage conversation state.

warning

Most proxies and third-party Responses API endpoints are stateless and will break if stateful mode is enabled. Only use this with providers that explicitly support stateful Responses API sessions.

Learn More​

This content is for informational purposes only and does not constitute a warranty, guarantee, or contractual commitment. Open WebUI is provided "as is." See your license for applicable terms.