Claude Failover

Anthropic API proxy with automatic key rotation, model fallback, and a local web dashboard.

Hit rate limits? Claude Failover automatically rotates through your API keys and falls back to cheaper models — zero client changes needed.

Quick Start

# Install globally from GitHub
sudo npm install -g Kentro-io/claude-failover

# Add your API keys
claude-failover add-key sk-ant-api03-... "Personal Account"

# Auto-configure your tools + install autostart (macOS LaunchAgent)
claude-failover setup --autostart

# Open the dashboard
open http://localhost:4080/dashboard

Auto-start: Run claude-failover setup --autostart once to install a macOS LaunchAgent. The proxy will start automatically on login — no need to manually run start again. To run manually instead: claude-failover start -d (daemon) or claude-failover start (foreground).

How It Works

┌──────────────────┐     ┌─────────────────────────┐     ┌───────────────┐
│  Claude Code     │     │  Claude Failover         │     │  Anthropic    │
│  Cursor          │────▶│  localhost:4080           │────▶│  API          │
│  Aider           │     │                          │     │               │
│  Any SDK Client  │◀────│  ● Key rotation on 429   │◀────│               │
│                  │     │  ● Model fallback         │     │               │
│                  │     │  ● Web dashboard          │     │               │
└──────────────────┘     └─────────────────────────┘     └───────────────┘

1. Point your tool at http://localhost:4080 instead of api.anthropic.com
2. The proxy tries your keys in priority order
3. On rate limit (429), it instantly rotates to the next key
4. When all keys are exhausted for a model, it falls back (e.g., Opus → Sonnet)
5. Monitor everything from the web dashboard

Features

Automatic Key Rotation

Add multiple API keys. When one hits a rate limit, the proxy instantly tries the next — no request dropped, no client error.

Model Fallback

Configure fallback chains (e.g., claude-opus-4-6 → claude-sonnet-4-6). When all keys are exhausted for Opus, the proxy automatically retries with Sonnet.

Web Dashboard

Real-time dashboard at localhost:4080/dashboard:

• Live metrics and status
• Add/remove/reorder API keys
• Configure profiles and fallback chains
• One-click setup for Claude Code, Cursor, and shell
• Real-time log viewer

Profiles

Create named profiles with different key orders, each on its own port:

• default on :4080 — key1 → key2 → key3
• claude-code on :4081 — key2 → key1 → key3

OAuth Token Support

Supports both API keys (sk-ant-api03-*) and OAuth tokens (sk-ant-oat01-*) with proper Bearer auth and beta headers.

Zero Dependencies

Pure Node.js — no npm packages, no supply chain risk, instant install.

Quick Update

Pull latest and restart:

cd ~/.local/lib/claude-failover && git pull origin main && claude-failover stop && claude-failover start -d

Or fresh install:

rm -rf ~/.local/lib/claude-failover && git clone https://github.com/Kentro-io/claude-failover.git ~/.local/lib/claude-failover && ln -sf ~/.local/lib/claude-failover/bin/cli.js ~/.n/bin/claude-failover && claude-failover stop && claude-failover start -d

OpenAI / GPT Fallback (NEW)

claude-failover now supports automatic fallback to OpenAI models when all Claude keys are exhausted.

Setup

# Add an OpenAI API key
claude-failover add-openai-key sk-proj-YOUR_KEY "GPT-5.4"

# Or add a ChatGPT subscription OAuth token
claude-failover add-openai-key YOUR_OAUTH_TOKEN "ChatGPT Pro"

Then enable fallback in ~/.config/claude-failover/config.json:

{
  "openaiModelFallback": true,
  "openaiModelMapping": {
    "claude-opus-4-6": "gpt-5.4",
    "claude-sonnet-4-6": "gpt-5.4-mini"
  }
}

How It Works

Claude Code request
  → Try Claude key 1 → rate limited
  → Try Claude key 2 → rate limited  
  → Queue (wait up to 90s for a key to free up)
  → All exhausted → Translate to OpenAI format → GPT-5.4
  → Translate response back → Claude Code gets normal Anthropic response

Claude Code never knows it's talking to GPT-5.4. The proxy handles all translation:

• Request format: Anthropic Messages API → OpenAI Chat Completions
• Response format: OpenAI → Anthropic (including streaming SSE)
• Tool use: Anthropic tool_use blocks ↔ OpenAI tool_calls
• Model mapping: configurable per-model

Use as Primary

To use GPT-5.4 as the primary model (skip Claude entirely), configure only OpenAI keys with no Claude keys, and set openaiModelFallback: true.

Dashboard

The dashboard at localhost:4080/dashboard shows:

• 🟠 Claude keys with Anthropic badge
• 🟢 OpenAI keys with OpenAI badge
• Fallback metrics (how many requests went to each provider)
• Model mapping configuration

CLI Reference

Command	Description
claude-failover start	Start proxy (foreground)
claude-failover start -d	Start as background daemon
claude-failover stop	Stop the daemon
claude-failover status	Show status and metrics
claude-failover add-key [token] [label]	Add an API key
claude-failover remove-key <id>	Remove a key
claude-failover list-keys	List configured keys
claude-failover setup	Auto-configure tools
claude-failover setup --autostart	Install macOS LaunchAgent
claude-failover config	Open web dashboard
claude-failover logs	Show recent logs
claude-failover logs -f	Follow logs in real-time
claude-failover health	Show health JSON

Configuration

Config is stored at ~/.config/claude-failover/config.json:

{
  "profiles": {
    "default": {
      "port": 4080,
      "keyOrder": ["personal", "work"]
    }
  },
  "keys": {
    "personal": {
      "token": "sk-ant-api03-...",
      "label": "Personal Account",
      "type": "api-key"
    }
  },
  "modelFallback": {
    "claude-opus-4-6": "claude-sonnet-4-6"
  },
  "cooldownMs": 3600000
}

Config hot-reloads every 5 seconds — edit the file or use the dashboard.

Supported Clients

Any tool that supports ANTHROPIC_BASE_URL:

Tool	Setup
Claude Code	claude-failover setup (auto) or set in ~/.claude/settings.json
Cursor	claude-failover setup (auto) or set base URL in settings
Aider	export ANTHROPIC_BASE_URL=http://localhost:4080
Python SDK	client = Anthropic(base_url="http://localhost:4080")
Node SDK	new Anthropic({ baseURL: "http://localhost:4080" })
curl	curl http://localhost:4080/v1/messages ...

Architecture

claude-failover/
├── bin/cli.js           # CLI entry point
├── src/
│   ├── server.js        # HTTP server + routing
│   ├── proxy.js         # Proxy engine (key rotation + fallback)
│   ├── config.js        # Config management + hot-reload
│   ├── cooldown.js      # Per-key per-model cooldown tracking
│   ├── metrics.js       # Request metrics + recent history
│   ├── logger.js        # Structured JSON logging
│   ├── daemon.js        # Background process + LaunchAgent
│   └── setup.js         # Auto-setup for tools
├── dashboard/
│   ├── index.html       # Dashboard SPA
│   ├── style.css        # Dark theme
│   └── app.js           # Dashboard logic (SSE, drag-drop)
└── package.json         # Zero dependencies

Security

• Keys never leave localhost — the proxy only binds to 127.0.0.1
• Config file uses 0600 permissions (owner read/write only)
• No telemetry, no external calls except to api.anthropic.com
• No dependencies = no supply chain risk

FAQ

Q: Does this work with streaming? A: Yes. The proxy pipes SSE streams through transparently — no buffering.

Q: What happens if all keys are exhausted? A: The proxy returns a 429 error with details about which keys and models were tried.

Q: Does it support per-model cooldowns? A: Yes. If key1 is rate-limited on Opus, it can still serve Sonnet requests.

Q: Can I use this in production? A: It's designed for local development use. For production, consider running behind a proper reverse proxy.

Requirements

• Node.js 18+
• macOS, Linux (Windows: experimental)

License

MIT