> For the complete documentation index, see [llms.txt](https://docs.fastrouter.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fastrouter.ai/integrations/app/open-webui.md). # Open WebUI ### What is Open WebUI? [Open WebUI](https://openwebui.com/) is a self-hosted, ChatGPT-style web interface for chatting with large language models. It runs entirely on your own infrastructure and connects to any server or provider that implements the OpenAI-compatible API. By routing Open WebUI through FastRouter, you get: * **100+ models** from OpenAI, Anthropic, Google, xAI, Meta, Groq, Mistral, and more through one endpoint—your whole team picks from a shared catalog with one key * **Observability** for every request: cost, tokens, latency, and model selection tracked in real time * **Reliability** through automatic failover across providers, response caching, and intelligent routing * **Governance** with per-key budgets, rate limits, model restrictions, role-based access, and project isolation This guide covers connecting Open WebUI to FastRouter by adding it as an OpenAI-compatible connection. **Prerequisites** * A FastRouter.ai account ([sign up](https://fastrouter.ai)) * A running Open WebUI instance with admin access ([installation guide](https://docs.openwebui.com/getting-started/)) *** #### Quick Start **Step 1: Get Your FastRouter API Key** 1. Sign up or log in at [fastrouter.ai](https://fastrouter.ai) 2. Navigate to your project's **Keys** page 3. Click **Create User Key** 4. Copy the key immediately. FastRouter does not display the key again after creation. **Step 2: Add FastRouter as a Connection** 1. Open Open WebUI in your browser. 2. Go to ⚙️ **Admin Settings** → **Connections** → **OpenAI**.
3. Click ➕ **Add Connection**.
3. Fill in: * **URL:** `https://api.fastrouter.ai/api/v1` * **API Key:** your FastRouter API key 4. Click **Save**.
**Step 3: Add the Models You Want** FastRouter exposes a large catalog, so rather than loading every model, add the specific slugs your team needs to the **Model IDs (Filter)** allowlist: 1. In the connection settings, find **Model IDs (Filter)**. 2. Type a FastRouter model slug—for example `openai/gpt-5.2`—and click the **+** icon. 3. Repeat for any other models (e.g., `anthropic/claude-4.5-sonnet`, `x-ai/grok-code-fast-1`). 4. Click **Save**.
> **Note:** Open WebUI verifies a connection by calling the provider's `/models` endpoint. Even if verification is slow or returns a warning, chat completions still work—the **Model IDs (Filter)** allowlist guarantees the models you listed appear in the selector. **Step 4: Start Chatting** Select a FastRouter model from the model dropdown in a new chat and send a message. The request routes through FastRouter, and every request, token count, and cost appears in your [FastRouter Dashboard](https://dashboard.fastrouter.ai/).
*** #### Use Open WebUI with 100+ Models FastRouter uses the `provider/model-name` format. Add any catalog slug to the connection's **Model IDs (Filter)** and it becomes selectable in the chat model dropdown: ``` anthropic/claude-4.5-sonnet google/gemini-3.1-pro-preview x-ai/grok-code-fast-1 ``` [Explore the full model catalog](https://fastrouter.ai/models) **Automatic Model Selection** Let FastRouter pick the best model for each request based on query complexity, domain, and cost. Add this slug to your **Model IDs (Filter)** and select it like any other model: ``` fastrouter/auto ``` [Explore automatic model selection](https://docs.fastrouter.ai/automatic-model-selection) *** #### FAQs **Configuration & Setup** **Connection verification shows an error, but is the connection broken?** Not necessarily. Verification calls the `/models` endpoint; if it is slow or returns a non-200, you'll see a warning, but chat completions still work. Make sure your models are listed in the **Model IDs (Filter)** allowlist, and they will appear in the selector regardless. **Do I need a trailing slash on the URL?** No. Use exactly `https://api.fastrouter.ai/api/v1` with no trailing slash. **Can I run multiple connections at once?** Yes. Each connection has a toggle to enable or disable it without deleting it, so you can keep FastRouter alongside other providers and switch as needed. **Can I restrict a key to only use specific models?** Yes. When creating or editing a key, use the **Select Models** setting to limit which models the key can access. FastRouter rejects requests to unauthorized models. **Costs & Budgeting** **How do I control spend across a team using one shared instance?** Set a budget and rate limit on the FastRouter key, and use Dynamic Tags to attribute spend. The Dashboard breaks down costs by project, key, model, and tag. **Privacy & Security** **Is my chat content sent to FastRouter's servers?** FastRouter acts as a pass-through gateway. Requests are routed to the model provider and responses are returned to your instance. Content logging can be disabled per key for sensitive workloads. See the **Disable Content Logging** option in key settings. For multi-user deployments, prefer a least-privilege key rather than an admin/master key. *** #### Next Steps * [Explore the full model catalog](https://fastrouter.ai/models) * [Set up Fallback Models](https://docs.fastrouter.ai/fallback-models) for high availability * [Configure Alerts](https://docs.fastrouter.ai/alerts) for spend and performance monitoring * [Run a Free Audit](https://fastrouter.ai/audit) on your existing LLM traffic to identify savings * [Join the Discord community](https://discord.gg/QfTgEtMyyU) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.fastrouter.ai/integrations/app/open-webui.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.