Zostaje MCP

Official, open-source MCP server for connecting a user's Zostaje account to ChatGPT and other MCP clients.

The repository is public, but financial data is not. Every request requires a user authorization token and the server exposes read-only tools by default.

Tools

• zostaje_status
• list_accounts
• get_monthly_summary
• list_transactions (bounded to at most 500 records per call)

The financial tools are implemented against the planned Zostaje API contract. They become usable when the corresponding endpoints and OAuth scopes ship in zostaje/backend.

Local development

cp .env.example .env
npm install
ZOSTAJE_ACCESS_TOKEN=development-secret npm run dev

The MCP endpoint is http://127.0.0.1:4200/mcp. The development token mode is for local tests only and supports one user.

Production security gate

Do not expose this server publicly with ZOSTAJE_ACCESS_TOKEN. Before remote deployment, replace DevelopmentTokenVerifier with Zostaje OAuth/OIDC token verification and publish protected-resource/authorization-server metadata. Required scopes should start with finance:read; write tools are intentionally out of scope.

ChatGPT connects to remote MCP servers. A public deployment therefore needs HTTPS, OAuth, refresh-token support (typically offline_access), rate limiting, audit logs and token revocation. The code must never log bearer tokens or return credentials in tool output.

Status

This is a safe integration scaffold, not yet a production connector. It refuses unauthenticated MCP calls and the backend currently exposes only /health.