Client Setup

Most clients require only an API key, endpoint, and model name. Follow the New Console Workflow to create and copy a key, then copy an available model name from the model catalog.

Setting	Value
API Key	An API key created in the console
OpenAI Base URL	https://www.fastapi.cool/v1
Anthropic Base URL	https://www.fastapi.cool
Model	A model name from the model catalog

The clients below are listed alphabetically.

CC Switch

CC Switch manages provider settings for Claude Code, Codex, OpenCode, OpenClaw, and other tools.

1. Open CC Switch and select the application you want to configure.
2. Click Add Provider and choose a custom configuration.
3. Enter Fast API as the name, then provide your API key and model name.
4. Use https://www.fastapi.cool for Claude Code. Use https://www.fastapi.cool/v1 for Codex, OpenCode, and OpenClaw.
5. Save the provider, select Fast API, and click Enable.

Restart the relevant terminal tool after switching providers. Claude Code usually applies the change immediately.

ChatBox / NextChat

1. Select OpenAI or OpenAI Compatible in the settings.
2. Set API Host / Base URL to:

https://www.fastapi.cool/v1

3. Enter your API key and model name, save, and send a test message.

Cherry Studio

1. Open Settings → Model Providers.
2. Add an OpenAI-compatible provider.
3. Set the API endpoint to https://www.fastapi.cool/v1.
4. Enter your API key and add the model name manually.
5. Run the connection test before using the provider.

Claude Code

Set the following environment variables:

macOS / Linux

export ANTHROPIC_BASE_URL="https://www.fastapi.cool"
export ANTHROPIC_AUTH_TOKEN="YOUR_API_KEY"
export ANTHROPIC_MODEL="YOUR_MODEL"
claude

Windows PowerShell

$env:ANTHROPIC_BASE_URL="https://www.fastapi.cool"
$env:ANTHROPIC_AUTH_TOKEN="YOUR_API_KEY"
$env:ANTHROPIC_MODEL="YOUR_MODEL"
claude

For persistent settings, add the variables to ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://www.fastapi.cool",
    "ANTHROPIC_AUTH_TOKEN": "YOUR_API_KEY",
    "ANTHROPIC_MODEL": "YOUR_MODEL"
  }
}

After startup, use /status to verify the active authentication method and /model to view or change the model.

CodeBuddy

CodeBuddy currently uses the OpenAI API format and requires the complete Chat Completions endpoint.

1. Create or edit ~/.codebuddy/models.json.
2. Add the following configuration and replace YOUR_MODEL with a name from the model catalog:

{
  "models": [
    {
      "id": "YOUR_MODEL",
      "name": "Fast API Model",
      "vendor": "OpenAI",
      "apiKey": "${FAST_API_KEY}",
      "url": "https://www.fastapi.cool/v1/chat/completions",
      "supportsToolCall": true
    }
  ],
  "availableModels": ["YOUR_MODEL"]
}

3. Set the API key and start CodeBuddy:

macOS / Linux

export FAST_API_KEY="YOUR_API_KEY"
codebuddy --model "YOUR_MODEL"

Windows PowerShell

$env:FAST_API_KEY="YOUR_API_KEY"
codebuddy --model "YOUR_MODEL"

For project-specific settings, place the same configuration in .codebuddy/models.json inside the project.

Codex CLI

Edit ~/.codex/config.toml:

model = "YOUR_MODEL"
model_provider = "fast_api"

[model_providers.fast_api]
name = "Fast API"
base_url = "https://www.fastapi.cool/v1"
env_key = "FAST_API_KEY"
wire_api = "responses"

Set the API key and start Codex:

macOS / Linux

export FAST_API_KEY="YOUR_API_KEY"
codex

Windows PowerShell

$env:FAST_API_KEY="YOUR_API_KEY"
codex

If the selected model supports only Chat Completions and not the Responses API, choose a model with Responses support.

Cursor

1. Open Cursor Settings → Models.
2. Expand API Keys and enter your OpenAI API key.
3. Enable Override OpenAI Base URL.
4. Set the Base URL to https://www.fastapi.cool/v1.
5. Add or select the model, click Verify, and test a text-only conversation.

Current compatibility

Cursor controls how its custom Base URL is used. In some versions, Agent mode, image input, or built-in Cursor models may not fully use the custom endpoint. If you encounter an error, test a plain text chat first or use another client from this page.

OpenClaw

Edit ~/.openclaw/openclaw.json and add an OpenAI-compatible provider:

{
  "agents": {
    "defaults": {
      "model": {
        "primary": "fast-api/YOUR_MODEL"
      }
    }
  },
  "models": {
    "mode": "merge",
    "providers": {
      "fast-api": {
        "baseUrl": "https://www.fastapi.cool/v1",
        "apiKey": "${FAST_API_KEY}",
        "api": "openai-completions",
        "models": [
          {
            "id": "YOUR_MODEL",
            "name": "Fast API Model"
          }
        ]
      }
    }
  }
}

Set the FAST_API_KEY environment variable and restart OpenClaw. The model reference must use the fast-api/YOUR_MODEL format.

OpenCode

Create opencode.json in the project root, or edit the user configuration at ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "fast-api": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "Fast API",
      "options": {
        "baseURL": "https://www.fastapi.cool/v1",
        "apiKey": "{env:FAST_API_KEY}"
      },
      "models": {
        "YOUR_MODEL": {
          "name": "Fast API Model"
        }
      }
    }
  },
  "model": "fast-api/YOUR_MODEL"
}

Set FAST_API_KEY, restart OpenCode, and select fast-api/YOUR_MODEL from the model list.

Troubleshooting

For a 401 error, check the API key. For a 404 error, make sure the URL does not contain /v1/v1 and that the model supports the selected protocol. For a model-not-found error, copy the model name from the model catalog again. If the request reached the platform, review its details in Usage Logs.