Mock

You can run a mock MCP server to test MCP clients and development workflows without needing a live production MCP instance. It supports stdio, HTTP, and Server-Sent Events transports so you can simulate different connection patterns and verify client behavior quickly.

How to use

Choose the transport you need and run the mock MCP server accordingly. For local testing with a simple in-process setup, use the stdio transport. For remote-like testing over HTTP, start a streamable HTTP endpoint. You can also test SSE-based clients by starting the SSE endpoint. After you start the server, configure your MCP client to point at the appropriate endpoint as shown in the examples.

How to install

Prerequisites: ensure you have the runtime available to execute the mock MCP server commands. You will run commands shown in the transport setup steps.

# Start a streamable HTTP MCP server on port 7788
uvx mock-mcp-server --transport http --host 127.0.0.1 --port 7788

# Start an SSE MCP server on port 7789
uvx mock-mcp-server --transport sse --host 127.0.0.1 --port 7789

# Start a local stdio-based MCP server using the in-process command
# This relies on the uvx runtime and the mock-mcp-server binary being available
# See the stdio configuration example for the command to run
uvx mock-mcp-server

Additional content

Below are concrete configuration examples for each transport so your MCP client can connect to the mock server. Use exactly these formats in your client setup.

Available tools

Mock MCP server CLI

A command-line tool to run a mock MCP server with configurable transport options (stdio, http, sse, and streamable-http). It enables you to start the server, listen on a host/port, and connect MCP clients to the mock endpoints.