MCP Registry: Definition, How It Works, and What It Isn't

An MCP registry is a catalog that lists MCP servers, so you can find them. Each entry holds a name, a description and a pointer to where the server lives, such as an npm package or a URL. It never holds the server's code, and it doesn't run anything for you.

A simple way to picture it

Think of a phone book. It tells you a business exists and where to find it. It doesn't answer the phone. Say you search a registry for "postgres" and get a package name back. You still have to install it, give it credentials and keep it running. That is the gap a hosted gateway fills.

What an entry contains

The official MCP Registry (registry.modelcontextprotocol.io) publishes each server as a server.json file. It has a name, a description, a package pointer, and the command, arguments and environment variables a host needs to launch it.

Names use a reverse-DNS format to stop squatting. A GitHub-verified publisher gets io.github.<user>/<server-name>, and a domain owner gets com.example/<server-name>.

Registry, marketplace and gateway

People use these words interchangeably, but they're three layers:

• Registry. Raw discovery data: a name mapped to a package or URL. Nothing is vetted beyond who owns the name.
• Marketplace. A curated set of servers with real config fields and tool lists, not just a package name.
• Gateway. The runtime layer. It runs the MCP server, holds its credentials and controls which tools a client can call.

A registry answers "what exists, and where?" It doesn't tell you whether a server is safe to call today.

The official MCP Registry today

As of September 2026, the official registry is still labeled a preview, with no confirmed general-availability date. It launched on September 8, 2025, backed by Anthropic, GitHub, PulseMCP and Microsoft. Publishers submit entries with the mcp-publisher CLI.

Host apps aren't meant to query it directly. Aggregators and marketplaces poll it and re-serve curated results. It checks namespace ownership, not code safety, and it doesn't accept private servers.

After you find a server

An entry hands you a package name or URL, not a working connection. With MCPifex, you skip the install step. Create an instance in the portal, save its credentials, pick the tools and connect any client to https://mcpifex.com/mcp. The quickstart walks through it.

For more background, see Model Context Protocol and the best MCP servers.