Open MCP Gateway

What it does

• Full transport coverage in one gateway: native binary stdio, script stdio, SSE and HTTP, unified with protocol wrapping, lifecycle self-healing and hot reloading
• Strict OpenAPI 3.1.0 contract — operationIds equal the original tool names, tools mount under requestBody.content['application/json'].schema
• Blue-green session pool: config updates swap sessions behind an AsyncMutex so in-flight requests never break; XDG-separated config/data/state/cache with ${APP_DATA_DIR}-style interpolation
• Single-binary deploy (bun build --compile, no runtime dependencies) and reverse-proxy friendly X-Forwarded-* parsing; per-server documents at /<server>/openapi.json register straight into Open WebUI's admin panel

When to use it

Teams that already run MCP servers locally and are standardising on Open WebUI (or any OpenAPI-consuming client): point the gateway at your stdio/SSE/HTTP servers once and every tool becomes a REST call without touching the servers themselves.

Getting started

# run from source (Bun 1.4+)
git clone https://github.com/TiancongLx/open-mcp-gateway.git
cd open-mcp-gateway && bun install && bun run dev

# or compile a single native executable
bun run build   # output: build/mcp-gateway

# config: $XDG_CONFIG_HOME/mcp-gateway/config.json5
# external MCP packages: cd $XDG_DATA_HOME/mcp-gateway && bun add <pkg>

Things to know

Built for the Open WebUI ecosystem — any OpenAPI client can consume the routes, but the integration docs and end-to-end tests target Open WebUI. Requires Bun 1.4+ at runtime (or the compiled binary); the config is JSON5, so comments and trailing commas will trip plain-JSON tooling. A community project, not affiliated with the Open WebUI team. MIT.