MCPJam Inspector
Test + develop ChatGPT apps and MCP apps (ext-apps) locally
151 followers
Test + develop ChatGPT apps and MCP apps (ext-apps) locally
151 followers
MCPJam inspector is the local testing tool for ChatGPT apps and MCP servers. Build your apps locally with MCPJam's widget emulator and test against any LLM in the playground. Inspect your MCP server’s tools, resources, prompts, and OAuth flows. No more ngrok or ChatGPT subscription needed.








MCPJam Inspector
Hey, it's Matt from MCPJam 👋.
We started MCPJam because the dev experience around building ChatGPT apps, MCP apps, and MCP servers wasn't great.
To develop a ChatGPT app, you had to get a ChatGPT pro subscription, ngrok you local MCP server, then connect it remotely on ChatGPT. There were also no good ways to test MCP servers and see how they behave in a real production environment.
That inspired us to build our open source inspector at MCPJam. We introduced:
Local ChatGPT and MCP apps emulator.
LLM playground to test your MCP server / apps in a real chat environment with any LLM
OAuth debugger to visualize MCP authorization at every step
and a bunch of other features that addresses the pains of MCP development.
If you're building a ChatGPT app, MCP app, or MCP server, I highly invite you to give us a try! Feel free to email me if you have any questions or feedback.
GitHub: https://github.com/MCPJam/inspector
Email: matthew@mcpjam.com
@matteo8p congrats on the launch. Does it also work with Claude Sonnet?
MCPJam Inspector
@austin_heaton Thank you Austin! It does have support for Claude Sonnet 4.5. You can provide your own API key, but we also provide Sonnet for free too!
Noodle Seed
MCPJam Inspector
@asadatnoodle Thank you Asad! Congrats on your launch too. Excited to see where the apps ecosystem goes.
Our team at Tadata builds MCP servers every day. We maintain one of the leading open source MCP projects and are shipping a large number of MCP servers for our agent builder. And we're huge fans of the OG MCPJam tool for debugging OAuth issues -- the visual flow is so helpful! Excited to try out the new stuff.
MCPJam Inspector
@tori_seidenstein Thanks for the support Tori! Been following Tadata for a long time, awesome to see your work on FastAPI MCP and now the agent builder on top of MCP! Really quality stuff.
Noodle Seed
MCPJam Inspector
@rehan_ali40 Thank you, congrats on the Noodle Seed launch too!
Noodle Seed
xmcp
Congratulations on the launch!
MCPJam Inspector
@valentina_bearzotti Thanks Val!
MCPJam is an amazing product with polished UX that has become our daily driver for troubleshooting. I only wish we had the OAuth inspector sooner, it would have saved us days of frustration! We now trust it as the de facto standard for validating new features. This is a must-have tool that feels like the start of an 'Android Studio' for ChatGPT apps. Good luck
MCPJam Inspector
@yaniv_shani1 Thank you for supporting Yaniv! I too wish we had the OAuth debugger out sooner haha.
Noodle Seed
Congratulations on the launch! MCPJam was clutch when we were building and testing MCP apps at Noodle Seed.
MCPJam Inspector
@saad_zafar Thank you Saad, I'm glad y'all found it useful building Noodle Seed.