By transport
MCP servers by transport
A transport is how an MCP client and server exchange messages. Of the 28,535 MCP Registry servers with a page here, 16,876 can be reached over the network and 13,314 run locally from a package; 1,655 offer both.
Servers per transport
A server that offers more than one transport is counted under each.
What each transport means
Streamable HTTP
The current MCP transport for servers reached over the network: one HTTPS endpoint that the client sends JSON-RPC messages to with POST, and that can answer with a single JSON response or a stream of server-sent events.
stdio (local process)
The client starts the server as a program on the same computer and exchanges JSON-RPC messages with it over standard input and output. Nothing is exposed on the network; the program runs with the user's own permissions.
SSE (HTTP + Server-Sent Events)
The earlier MCP transport for remote servers: the client opens a Server-Sent Events stream to receive messages and posts its own messages to a second URL the server names. The protocol has since moved to Streamable HTTP; many clients still accept SSE.