MCP Gateway ORG

A generic, subclassable Model Context Protocol gateway whose tools are registered and executed
asynchronously by connected providers over WebSocket.

MCP Client ⇄ Streamable HTTP ⇄ Gateway ⇄ WebSocket ⇄ Provider

---

The gateway never knows the capabilities ahead of time. A provider — typically a browser app —
connects, publishes its own MCP tools, resources, prompts and more, and executes them when an MCP
client calls them. The gateway only registers, publishes and routes, staying completely domain
agnostic.

It is a small, installable library. You build a real application by subclassing Gateway and
overriding hooks. The handlers themselves are written in JavaScript. This library never prescribes a
specific frontend — the [Provider SDK](docs/provider-sdk.md) guide teaches the JS side generically.

📦 Install

bash
pip install mcp-gtw
# or
uv add mcp-gtw

🚀 The smallest gateway

python
from mcp_gtw.gateway import Gateway

app = Gateway().create_app()

bash
uv run python -m mcp_gtw.main

This publishes a real MCP endpoint at /mcp, a private provider WebSocket at /provider and a health
check at /health. It exposes whatever capabilities the connected provider registers.

☁️ One-click deploy

The image runs production-ready as a non-root process. Deploy it to any host that keeps a persistent
server (the /provider WebSocket needs one — serverless like Vercel does not work):


Render, Railway and Fly.io run the [Dockerfile](Dockerfile) as-is (they inject PORT, which the
gateway reads); on a VPS (Hostinger, …) use Docker Compose. Full guide, including reverse proxy and
TLS: [deployment](docs/deployment.md).

🧩 Extending it

Subclass Gateway and override the hooks to attach your own domain logic:

python
from mcp_gtw.channel import Channel
from mcp_gtw.gateway import Gateway

class MyGateway(Gateway):
    mcp_server_name = "my-app"

    async def on_provider_connected(self, channel: Channel) -> None:
        ...  # a provider session just came online

    def register_routes(self, app) -> None:
        super().register_routes(app)
        ...  # add your own HTTP and WebSocket routes

app = MyGateway().create_app()

Every behaviour is a swappable strategy with a secure default — authentication, tokens, origins,
expiry and the wire codec. Change one by setting a *_class attribute or injecting an instance,
without touching the transport. See the [Gateway library](docs/gateway-library.md) guide for every
override point, [Extensibility](docs/extensibility.md) for the strategy contracts, and
[Auth recipes](docs/auth-recipes.md) for token, username/password and client-supplied-token models.

📚 Documentation

| Guide | What it covers |
| --- | --- |
| [Architecture](docs/architecture.md) | Components, transports and request flows. |
| [Quick start](docs/quickstart.md) | Install, run and connect an MCP client. |
| [Gateway library](docs/gateway-library.md) | The Gateway class and every override point. |
| [Extensibility](docs/extensibility.md) | The swappable strategies, their contracts and the invariants. |
| [Auth recipes](docs/auth-recipes.md) | Token, username/password and client-supplied-token models. |
| [Configuration](docs/configuration.md) | Every setting and environment variable. |
| [Provider protocol](docs/provider-protocol.md) | The private gateway ⇄ provider message protocol. |
| [Provider SDK](docs/provider-sdk.md) | Writing the JavaScript provider and registering tools. |
| [Browser console](docs/browser-console.md) | Turn any open page into a provider from DevTools. |
| [MCP clients](docs/mcp-clients.md) | Connecting Claude Code, generic clients and the Inspector. |
| [Admin dashboard](docs/admin.md) | The optional monitoring dashboard and its stats API. |
| [Security](docs/security.md) | The security model, tokens, origins and hardening. |
| [Testing](docs/testing.md) | Running the suite and the 100% coverage gate. |
| [Deployment](docs/deployment.md) | Docker, reverse proxies and scaling. |

🗂️ Layout

text
.
├── src/mcp_gtw/     # the library
├── tests/               # unit and integration tests (100% coverage)
└── docs/                # the guides linked above

✅ Requirements

• Python 3.12+ — tested on 3.12, 3.13 and 3.14 in CI (3.12 is the pinned local and Docker version)
• Any MCP client (Claude Code, Cursor, the MCP Inspector, …)

💜 Support

If this project saved you time, consider supporting it:
GitHub Sponsors · Ko-fi.

Made with care by Paulo Coutinho.

Licensed under [MIT](LICENSE.md).

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