Ship a ChatGPT App in 2 Commands
The default carousel ChatGPT App built and deployed with sunpeak.
[Updated 2026-02-05] With sunpeak, you can start and ship a ChatGPT App with two commands:
TL;DR: Run pnpm add -g sunpeak && sunpeak new, then sunpeak dev. Expose via ngrok and add the URL to ChatGPT’s Apps & Connectors settings.
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Install sunpeak globally and initialize your project:
pnpm add -g sunpeak && sunpeak new -
Inside your project, start your mcp server:
sunpeak dev
Your ChatGPT App UI and mock data server is now up and running.
If you’re running the server on your local machine, you’ll need to expose that MCP server so ChatGPT can access it. Do so with a free account from ngrok:
ngrok http 6766Lastly, you need to point ChatGPT to your new app. From your ChatGPT account, proceed to: User > Settings > Apps & Connectors > Create
You need to be in developer mode to add your App, which requires a paid account. If you don’t have a paid account, you can just develop your App locally with pnpm dev.
You can now connect ChatGPT to the ngrok Forwarding URL at the /mcp path (e.g. https://your-random-subdomain.ngrok-free.dev/mcp). Your App is now connected to ChatGPT! Send /sunpeak show carousel to ChatGPT to see your UI in action!
Learn more about the ChatGPT App framework or check out the sunpeak documentation.
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Frequently Asked Questions
What are the two commands to create and run a ChatGPT App?
First, run "pnpm add -g sunpeak && sunpeak new" to install sunpeak globally and create your project with all dependencies. Second, run "sunpeak dev" inside your project to start both the MCP server (port 6766) and the sunpeak ChatGPT App simulator (port 6767).
How do I expose my local ChatGPT App to the real ChatGPT?
Use ngrok to create a public tunnel with "ngrok http 6766". Copy the Forwarding URL and add it with the /mcp path (e.g., https://abc123.ngrok-free.dev/mcp) in ChatGPT under User > Settings > Apps & Connectors > Create.
Do I need a paid ChatGPT account to build ChatGPT Apps?
No. You can develop and test locally using the sunpeak simulator at localhost:6767 without any ChatGPT account. A paid ChatGPT Plus or Team subscription with developer mode is only required to connect your ChatGPT App (built as an MCP App) to the real ChatGPT.
What is sunpeak and why use it for ChatGPT Apps?
Sunpeak is an open-source ChatGPT App framework (built on MCP) described as "Next.js for MCP Apps." It provides project scaffolding, a ChatGPT App simulator, MCP server with hot reloading, pre-built UI components, and CLI tools—everything needed to build ChatGPT Apps and MCP Apps quickly.
What is ngrok and why do I need it for ChatGPT App development?
Ngrok creates secure tunnels from the internet to your local machine. ChatGPT needs a public URL to connect to your MCP server, and ngrok provides this during development. A free ngrok account is sufficient for sunpeak ChatGPT App development purposes.
How do I test my ChatGPT App after connecting to ChatGPT?
After adding your ngrok URL in ChatGPT's Apps & Connectors settings, start a new conversation and send a message like "/sunpeak show carousel" to invoke your ChatGPT App's tools and see your UI rendered in the chat.
What port does the sunpeak MCP server run on for ChatGPT Apps?
The sunpeak MCP server runs on port 6766 by default. When using ngrok, tunnel to this port with "ngrok http 6766". The sunpeak ChatGPT App simulator UI runs separately on port 6767.
Can I develop ChatGPT Apps without ngrok?
Yes. For local development, the sunpeak simulator at localhost:6767 fully replicates the ChatGPT environment. Ngrok is only needed when you want to test your ChatGPT App (built as an MCP App) in the actual ChatGPT interface or share it with others.
