Test & debug MCP servers

MCPJam Inspector is the local-first testing platform for MCP servers. Inspect the protocol handshake and verify your server's tools, resources, prompts, and OAuth. Test your server against different models in the LLM playground.
Now with support for OpenAI Apps SDK.

Spin up the inspector locally:

npx@mcpjam/inspector@latest

Or download the desktop app

MCPJam Inspector preview

Tools

3

Echo

Echo the message back to you.

message

Text to echo.

string

Response

Execute a tool to see results here.

OAuth Debugger

Visualize and debug MCP authorization flows. Verify that your OAuth implementation conforms to the MCP spec at every step.

Inspect at the JSON-RPC level

Debug every JSON-RPC message sent to and from your MCP server. Instantly find errors and root causes.

Inspect at the JSON-RPC level

Support for OpenAI Apps SDK

Test MCP servers built with Apps SDK locally. No ngrok needed.

LLM playground

Test your MCP server against different models in the LLM playground. We provide free models too.

Contact us

We are happy to help with your MCP strategy. Tell us about what you're building and we'll get in touch with you.

or email us at founders@mcpjam.com

MCPJam - Test and debug MCP servers