CAPI Gateway

CAPI Gateway is a lightweight, open-source MCP (Model Context Protocol) server and API gateway built in Java. Its primary capability is bridging any existing REST API (and optionally gRPC services) into the MCP tool protocol, making them accessible to LLM agents (like Claude, Cursor, and other MCP-compatible clients) without requiring changes to backend services. It offers service discovery (via HashiCorp Consul), robust authentication (OAuth2/OIDC, API Keys), authorization (OPA), distributed throttling, metrics (Prometheus), tracing (OpenTelemetry), and can aggregate tools from both REST and native MCP servers. Target users include AI app developers, enterprises, and teams seeking to rapidly expose services and tools to LLMs in a unified, secure, and scalable manner.