MCP server for Firefly III

An MCP (Model Context Protocol) server that connects any MCP-compatible AI assistant to your Firefly III personal finance instance. Ask your AI assistant questions about your finances in natural language.

📖 Full documentation → daften.github.io/fireflyiii-mcp

What you can ask

Once configured, you can ask things like:

• “How much did I spend on groceries last month?”
• “Show me my budget status for this month.”
• “Find any duplicate transactions in the last 30 days.”
• “Set up a piggy bank for my vacation fund with a €2000 target.”
• “What were my biggest expense categories this year?”

Your AI assistant handles the Firefly III API calls — you get answers in plain language.

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Choose your setup method:

All options except Docker require Node.js 22.12+.

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Option 1: npm package — stdio (simplest)

Requires: Node.js 22.12+, a Firefly III Personal Access Token (Options → Remote access and tokens → Create new token).

Add to your Claude MCP config (.claude/mcp.json or Claude Desktop claude_desktop_config.json):

{
  "mcpServers": {
    "fireflyiii": {
      "command": "npx",
      "args": ["-y", "@daften/fireflyiii-mcp"],
      "env": {
        "FIREFLY_URL": "https://your-firefly-instance.example.com",
        "FIREFLY_TOKEN": "your-personal-access-token-here"
      }
    }
  }
}

Your MCP client downloads and starts the server automatically on first use. No separate install step needed.

Claude Desktop users: this stdio form is the recommended setup. Claude Desktop’s config file does not accept HTTP servers — see the Claude Desktop guide if you need a remote setup.

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Option 2: npm package — HTTP (OAuth or PAT)

→ See the HTTP/OAuth setup guide, or HTTP/PAT for headless callers (gateways, automation) that can’t drive a browser-based OAuth flow.

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Option 3: Docker — HTTP (self-hosted)

→ See Docker setup guide in the docs.

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Option 4: Git checkout (development)

→ See Git checkout guide in the docs.

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Nightly builds (unstable)

Want to test unreleased changes from main? A nightly build is published automatically each night that main has changed. These are unstable and not recommended for production.

• npm: npm install @daften/fireflyiii-mcp@nightly (or npx @daften/fireflyiii-mcp@nightly)
• Docker: docker pull ghcr.io/daften/fireflyiii-mcp:nightly

A normal install (no tag) always resolves to the latest tagged release — @latest on npm and :latest on Docker are never moved to a nightly. To go back to a stable build, reinstall without the @nightly / :nightly tag.

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Experimental Autocomplete Prompts

→ See Autocomplete prompts in the docs.

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Available Tools

→ See the full tool reference in the docs (140 tools across 14 groups).

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Filtering Tools

→ See Tool filtering in the docs.

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Development

npm test                  # Run unit tests
npm run test:watch        # Watch mode
npm run test:integration  # Run against live Firefly III (requires FIREFLY_URL + FIREFLY_TOKEN)
npm run dev               # Run without building (uses tsx)
npm run build             # Compile TypeScript to dist/

Resources

• Firefly III API Documentation — interactive Swagger UI for all API versions
• Firefly III OpenAPI YAML — machine-readable spec; fetch with curl -s "https://api-docs.firefly-iii.org/firefly-iii-6.5.5-v1.yaml" -A "Mozilla/5.0" (direct browser access blocked by bot protection)
• Firefly III Docs
• MCP Documentation

Contributing

See CONTRIBUTING.md for the development loop, tool-add checklist, and commit conventions.

Security

See SECURITY.md for the vulnerability disclosure policy.

Acknowledgements

Feature comparison informed by fabianonetto/mcp-server-firefly-iii and etnperlong/firefly-iii-mcp.

License

MIT