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Overview

Open WebUI supports OpenAI’s API and any OpenAI-compatible API endpoints, including Azure OpenAI, Anthropic, Google AI, and custom providers.

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Quick Start

1

Get API Key

Obtain an API key from your provider (OpenAI, Azure, etc.)
2

Configure Environment

Set the API key and base URL
3

Enable OpenAI API

Enable in Admin Panel or set ENABLE_OPENAI_API=True

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Configuration

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OpenAI

OPENAI_API_KEY=sk-proj-...
OPENAI_API_BASE_URL=https://api.openai.com/v1
ENABLE_OPENAI_API=True

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Azure OpenAI

OPENAI_API_KEY=your-azure-key
OPENAI_API_BASE_URL=https://your-resource.openai.azure.com
Azure OpenAI requires deployment names. The model ID in Open WebUI should match your Azure deployment name.File: backend/open_webui/routers/openai.py:800

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Advanced Configuration

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Authentication Types

Open WebUI supports multiple authentication methods: 
{
  "auth_type": "bearer",
  "key": "your-api-key"
}
File: backend/open_webui/routers/openai.py:149

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Custom Headers

Add custom headers to API requests: 
{
  "OPENAI_API_CONFIGS": {
    "0": {
      "headers": {
        "X-Custom-Header": "value",
        "Authorization": "Custom auth-scheme token"
      }
    }
  }
}

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Model Filtering

Specify which models to expose: 
{
  "OPENAI_API_CONFIGS": {
    "0": {
      "model_ids": [
        "gpt-4-turbo",
        "gpt-4",
        "gpt-3.5-turbo"
      ]
    }
  }
}

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Connection Types

Tag connections as local or external: 
{
  "OPENAI_API_CONFIGS": {
    "0": {
      "connection_type": "local",
      "prefix_id": "local",
      "tags": ["fast", "private"]
    },
    "1": {
      "connection_type": "external",
      "prefix_id": "cloud",
      "tags": ["cloud", "gpt4"]
    }
  }
}
File: backend/open_webui/routers/openai.py:421

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OpenAI-Compatible Providers

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Anthropic

OPENAI_API_BASE_URL=https://api.anthropic.com/v1
OPENAI_API_KEY=sk-ant-...
Open WebUI automatically detects Anthropic URLs and uses appropriate model mapping. File: backend/open_webui/routers/openai.py:96

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Google AI (Gemini)

GEMINI_API_KEY=your-gemini-key
GEMINI_API_BASE_URL=https://generativelanguage.googleapis.com/v1

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OpenRouter

OPENAI_API_BASE_URL=https://openrouter.ai/api/v1
OPENAI_API_KEY=sk-or-...
OpenRouter requires specific headers: 
{
  "OPENAI_API_CONFIGS": {
    "0": {
      "headers": {
        "HTTP-Referer": "https://openwebui.com/",
        "X-Title": "Open WebUI"
      }
    }
  }
}
File: backend/open_webui/routers/openai.py:134

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Local Providers

OPENAI_API_BASE_URL=http://localhost:1234/v1
OPENAI_API_KEY=lm-studio

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Reasoning Models (o1, o3)

Open WebUI automatically handles OpenAI’s reasoning models: 
// Converts max_tokens to max_completion_tokens
// Converts system role to user role
File: backend/open_webui/routers/openai.py:101

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Responses API

For providers supporting OpenAI’s Responses API: 
{
  "OPENAI_API_CONFIGS": {
    "0": {
      "api_type": "responses"
    }
  }
}
Automatic conversion from Chat Completions to Responses API format: File: backend/open_webui/routers/openai.py:827

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API Endpoints

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Model Management

  • GET /openai/models - List available models
    File: backend/open_webui/routers/openai.py:556
  • POST /openai/verify - Verify connection and API key
    File: backend/open_webui/routers/openai.py:659

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Completions

  • POST /openai/chat/completions - Chat completions
    File: backend/open_webui/routers/openai.py:936
  • POST /openai/responses - Responses API (experimental)
    File: backend/open_webui/routers/openai.py:1256

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Audio

  • POST /openai/audio/speech - Text-to-speech
    File: backend/open_webui/routers/openai.py:272

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Embeddings

For RAG and semantic search: 
# Automatically routed based on model
POST /openai/embeddings
{
  "model": "text-embedding-3-small",
  "input": "Your text here"
}
File: backend/open_webui/routers/openai.py:1151

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Troubleshooting

  1. Verify the API key format
  2. Check for leading/trailing whitespace
  3. Ensure the key has necessary permissions
  4. Test with the provider’s verify endpoint
OpenAI API filters out certain models by default:
  • Embedding models
  • TTS/Whisper models
  • DALL-E models
  • Legacy babbage/davinci models
File: backend/open_webui/routers/openai.py:505
Common issues:
  • Deployment name doesn’t match model ID
  • Incorrect API version
  • Missing api-key header for non-Entra auth
  • Unsupported parameters for API version
Allowed parameters vary by API version.File: backend/open_webui/routers/openai.py:754
Open WebUI respects provider rate limits. Consider:
  • Using multiple API keys with load balancing
  • Implementing backoff in Pipelines
  • Monitoring usage through provider dashboard

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Advanced Features

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Logit Bias

Control token generation probabilities: 
{
  "logit_bias": {
    "1234": -100,
    "5678": 100
  }
}
File: backend/open_webui/routers/openai.py:1058

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User Info Forwarding

Forward user context to API: 
ENABLE_FORWARD_USER_INFO_HEADERS=true
Headers:
  • X-OpenWebUI-User-Name
  • X-OpenWebUI-User-Id
  • X-OpenWebUI-User-Email
  • X-OpenWebUI-User-Role
  • X-OpenWebUI-Chat-Id
File: backend/open_webui/routers/openai.py:80

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Model Caching

Models are cached for performance: 
MODELS_CACHE_TTL=300  # 5 minutes
File: backend/open_webui/routers/openai.py:482

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Best Practices

Use Environment Variables

Keep API keys in environment variables, not in database

Multiple Keys

Configure multiple API keys for load balancing and redundancy

Model Access Control

Use Open WebUI’s RBAC to control model access per user

Monitor Costs

Track usage through provider dashboards and OpenTelemetry