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Anthropic (Claude)

Overview​

Open WebUI supports Anthropic's Claude models natively through their OpenAI-compatible endpoint. Just plug in your API key and start chatting: no middleware, no pipes, no extra setup required.

Open WebUI detects Anthropic URLs (any URL containing api.anthropic.com) and handles model discovery for them: the native models list is paged with x-api-key and reshaped into the OpenAI list format. Chat requests themselves are sent unchanged to Anthropic's OpenAI-compatible /v1/chat/completions with Bearer auth. Open WebUI also exposes its own Anthropic Messages endpoint at /api/v1/messages, and for a connection on api.anthropic.com those requests are passed through natively to /v1/messages, outside the chat pipeline.

Anthropic's Compatibility Disclaimer

Anthropic states that their OpenAI-compatible API is intended for evaluation and testing, not production workloads. In practice, everything (including tool calling) works as intended, but be aware of this official stance. For full Claude-native features (PDF processing, citations, extended thinking, prompt caching), Anthropic recommends their native /v1/messages API, which can be accessed via a pipe function or a proxy like LiteLLM.

Step 1: Get Your API Key​

  1. Go to console.anthropic.com.
  2. Create an account or sign in.
  3. Navigate to API Keys and generate a new key.

Step 2: Add the Connection in Open WebUI​

  1. Open Open WebUI in your browser.
  2. Go to Settings > Admin > Connections and find the Manage OpenAI API Connections list.
  3. Click ➕ Add Connection.
  4. Enter the following:
SettingValue
URLhttps://api.anthropic.com/v1
API KeyYour Anthropic API key
  1. Click Save.
tip

The URL field will suggest common provider endpoints as you type, just select the Anthropic URL from the dropdown.

Step 3: Start Chatting!​

That's it! Open WebUI automatically detects the Anthropic endpoint and fetches available models. Select a Claude model from the model dropdown and you're good to go.

Streaming, multi-turn conversations, and tool calling all work seamlessly.

Optional: Filter Models

If you want only specific models to appear, you can add model IDs to the Model IDs allowlist in the connection settings. Common model IDs:

ModelID
Claude Opus 5claude-opus-5
Claude Sonnet 5claude-sonnet-5
Claude Haiku 4.5claude-haiku-4-5

Check Anthropic's model documentation for the latest available model IDs.

Managing Your Connection​

You can enable or disable your Anthropic connection at any time using the toggle switch next to the connection entry. This lets you temporarily deactivate a provider without deleting the connection or losing your configuration.

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.