What Is an MCP Gateway? Definition and How It Works

An MCP gateway is one endpoint that sits in front of MCP servers. Your AI client connects to a single address instead of many. The gateway handles authentication, routing and which tools each caller may use, so you set those rules in one place.

A simple way to picture it

Think of a front desk in an office building. Visitors don't wander the halls. They check in, show a badge and get sent only where they're allowed. A gateway does that for AI. Your client shows a key, and the gateway connects it to the right MCP server and only lets it use the tools you've approved.

What a gateway adds

Talking to a server directly means you manage its process and its credentials, and you trust it with every tool it offers. A gateway puts a policy layer in between:

• One place for auth. A single key gates access, no matter how the server itself logs in. See MCP authentication.
• Per-tool allow and deny. The client only sees enabled tools, and calls to anything else are refused.
• Session isolation. Each client session gets its own server process, ended when the session closes.
• Logging. Every call is recorded, so you can check usage later.

How it works under the hood

As of September 2026, MCP defines two official transports: stdio for a local subprocess and Streamable HTTP for the network. A gateway usually speaks Streamable HTTP to your client and starts each server over stdio on the other side. It translates between the two, so the servers are never exposed directly.

Self-hosted or hosted

Most gateways are software you run yourself. Docker's MCP Gateway is the well-known example. It runs each server in its own container and manages its credentials, but you install it and keep it running.

A hosted gateway flips that. The provider runs the servers and you point a client at a URL. For the trade-offs, see MCPifex vs Docker MCP Gateway and MCP gateway vs proxy.

MCPifex as a gateway

MCPifex is a hosted gateway at https://mcpifex.com/mcp. You create an instance of a server in the portal, save its credentials, choose the tools and get an API key. Read the quickstart to connect a client in a few minutes, or browse the marketplace.

For background, see Model Context Protocol and remote MCP server.