sunpeak is a server‑agnostic framework for building, testing, and deploying MCP Apps—interactive UIs that run inside AI hosts such as ChatGPT and Claude via the Model Context Protocol. It offers convention‑over‑configuration tooling, a hot‑reloading dev server, and 20+ typed React hooks, enabling developers to write an app once and launch it across multiple MCP‑compatible platforms while simulating host environments for CI/CD testing without needing actual accounts or API credits.
Funding
Funding not disclosed
Founders
Product
Problem
Developers building interactive UIs for AI hosts such as ChatGPT and Claude must manage host-specific protocols, resource bundling, and runtime environments, which requires extensive setup, multiple codebases, and manual testing within opaque host iframes.
Solution
Sunpeak offers a server‑agnostic framework that streamlines the creation, testing, and inspection of MCP Apps—cross‑platform UI tools that run inside AI hosts via the Model Context Protocol. The framework provides convention‑over‑configuration scaffolding, a hot‑reloading development server, and a library of typed React hooks and pre‑built UI components that abstract host differences. Integrated testing tools replicate ChatGPT and Claude runtimes, enabling unit, end‑to‑end, visual regression, and live host tests without needing API credentials or host accounts. An inspector UI mirrors the actual host environments locally, allowing developers to see and debug their apps instantly. With a single codebase, apps can be deployed to multiple MCP‑compatible hosts.
Target Audience
Primary users are developers building AI‑hosted interactive tools—such as ChatGPT Apps, Claude Connectors, and other MCP‑compatible applications—who need a unified workflow for development, testing, and deployment.
Features
- Convention‑over‑configuration project scaffolding with auto‑discovered resources, tools, and simulation fixtures
- Over 20 typed React hooks (e.g., useToolData, useAppState, useTheme, useDisplayMode) for unified cross‑host development
- Hot‑module‑reloading dev server that rebuilds automatically for ChatGPT and notifies Claude runtimes
- Pre‑built UI components that follow ChatGPT and Claude design guidelines
- Playwright‑based testing suite that simulates host runtimes, supports visual regression, live host tests, and multi‑model evals
- Local inspector that replicates ChatGPT and Claude app runtimes, allowing host, theme, and display‑mode switching without deployment
- CLI commands for project creation, development, building, production serving, testing, and inspection