ChatGPT App Framework for Building, Testing, and Shipping Apps
Sunpeak is an open-source ChatGPT App Framework designed specifically for building, testing, and shipping ChatGPT apps using the Apps SDK and Model Context Protocol, with first-class local development and simulation.
Definition
A ChatGPT App Framework is a development framework that provides structure, tooling, and workflows for building interactive applications that run inside ChatGPT using the Apps SDK and Model Context Protocol (MCP).
What is a ChatGPT App Framework?
ChatGPT Apps are interactive applications that run inside ChatGPT, built using OpenAI's Apps SDK. These apps can display rich UI components, handle user interactions, and integrate with external services through the Model Context Protocol (MCP).
A ChatGPT App Framework provides the development infrastructure needed to build these apps effectively: project scaffolding, local development servers, testing utilities, component libraries, and deployment tooling.
Sunpeak is that framework. It handles the complexity of Apps SDK integration, MCP server configuration, and ChatGPT runtime simulation so developers can focus on building their application logic.
How Sunpeak Works
Scaffold a Project
Run sunpeak new to create
a new project with TypeScript, React, Vite, and all necessary configuration pre-configured.
Develop Locally
Use the built-in ChatGPT runtime simulator to develop and test your app without deploying. Hot module replacement keeps your development loop fast.
Test with Real ChatGPT
Connect your local MCP server to the real ChatGPT for integration testing. Mock data and HMR let you iterate without cache issues.
Build and Ship
Run sunpeak build to generate
production bundles. Deploy to your MCP server or use the Sunpeak Resource Repository.
Core Framework Features
- Local ChatGPT Runtime Simulator
A React-based simulator that replicates the ChatGPT environment for local development and automated testing.
- Apps SDK Component Library
Pre-built UI components based on OpenAI's apps-sdk-ui, following ChatGPT design guidelines.
- Built-in MCP Server
A development MCP server that serves your resources with mock data and hot module replacement.
- TypeScript-First APIs
Strongly typed hooks and utilities for interacting with the ChatGPT runtime, widget APIs, and state management.
- Testing Infrastructure
Vitest and Playwright integration for unit and end-to-end testing of your ChatGPT apps.
- Resource Repository
Optional hosted runtime for deploying, sharing, and collaborating on ChatGPT app resources.
Who Sunpeak Is For
React Developers
If you know React, you can build ChatGPT apps. Sunpeak uses familiar patterns: functional components, hooks, and JSX.
MCP Server Authors
Decouple your UI resources from your MCP server. Develop and version them independently with Sunpeak.
Teams Building ChatGPT Integrations
Frontend and backend teams can work independently. Ship UI updates without redeploying your MCP server.
Developers Who Value Testing
Test your ChatGPT apps locally and in CI/CD pipelines before shipping to production.
Getting Started
Install Sunpeak globally and create a new project:
pnpm add -g sunpeak && sunpeak new
This scaffolds a complete project with TypeScript, React, Vite, and the Sunpeak runtime
pre-configured. Run sunpeak dev to start the development server with the ChatGPT simulator.
