- Runs it
- Model Context Protocol project
- Projects
- 20
- Official
- 1
- Stars checked
- 2026-11-08
- Spec
- official
MCP Apps SDKs and Examples: 20 open-source projects compared
Give your MCP server a real interface inside Claude, ChatGPT and VS Code. Compare 20 open-source MCP Apps SDKs, servers and examples by stars, licence and activity.
Compare MCP Apps projects
These 20 open-source projects implement or support MCP Apps. 1 are maintained by the official project and the rest by the community. Sort by stars or recent activity, or filter by type. These projects are listed from public GitHub data and are not scanned by AgenticMart.
mcp-use
Full-stack framework for MCP servers and MCP Apps
MCP-UI
SDK and React components for rendering UI over MCP
Skybridge
Full-stack TypeScript and React framework for MCP Apps and ChatGPT Apps
sunpeak
Testing framework and full-stack framework for MCP Apps
mcpcn
React component set for building MCP Apps in the shadcn/ui style
Manifest UI
shadcn/ui component library for ChatGPT Apps and MCP Apps
Stars and activity checked 2026-11-08. These projects are listed from public GitHub data and are not scanned by AgenticMart. Built one? List it free now, paid selling opens soon.
What is MCP Apps?
MCP Apps are an extension to the Model Context Protocol that lets servers return interactive HTML interfaces rendered inside the chat. A tool declares a ui:// resource, the host renders it in a sandboxed iframe, and the app talks to the host over JSON-RPC through postMessage. Host support varies by client.
MCP Apps vs MCP-UI: what is the difference
MCP Apps is the official extension that standardizes ideas first used in MCP-UI. It keeps the two-way communication and HTML content model, but it swaps MCP-UI's custom handshake and message format for ui/initialize and JSON-RPC. The specification notes breaking changes, which the MCP-UI SDK is expected to handle during migration. New to MCP? Read what an MCP server is.
What an MCP Apps message looks like
An MCP server declares an interactive view as a resource with a ui:// URI and the text/html;profile=mcp-app MIME type. A tool then points at this URI through its _meta.ui.resourceUri field so the host can render the HTML in a sandboxed iframe.
{
"uri": "ui://weather-server/dashboard-template",
"name": "weather_dashboard",
"description": "Interactive weather dashboard view",
"mimeType": "text/html;profile=mcp-app"
}From the official specification, checked 2026-11-12.
MCP Apps questions
What are MCP Apps?
MCP Apps are an MCP extension that lets a server show an interactive interface, such as a chart, form or dashboard, inside the chat. Instead of only returning text, a tool can point to an HTML interface that the host displays in place.
MCP Apps vs MCP-UI: what is the difference?
MCP Apps is the official extension that standardizes ideas first used in MCP-UI. It keeps the two-way communication and HTML content model, but it swaps MCP-UI's custom handshake and message format for ui/initialize and JSON-RPC. The specification notes breaking changes, which the MCP-UI SDK is expected to handle during migration.
How are MCP Apps related to the OpenAI Apps SDK?
They are separate efforts, and the MCP Apps specification says the OpenAI Apps SDK showed demand for rich interfaces and informed its design. As of November 2026, the MCP Apps repository also lists ChatGPT among the clients where these apps can appear.
How do I build an MCP App?
Install @modelcontextprotocol/ext-apps on Node.js 20 or later and follow the quickstart guide in the ext-apps repository. The repository has starter templates for React, Vue, Svelte, Preact, Solid and plain JavaScript. The App class is a convenience, so you can also implement the postMessage protocol directly.
How do MCP Apps work?
A tool declares a ui:// resource, and when the tool is called the host fetches that HTML and shows it in a sandboxed iframe. The app and host then exchange JSON-RPC messages through postMessage. This lets the app receive tool results and ask the host to call more tools.
What are the security risks of MCP Apps?
MCP Apps run third-party HTML inside the chat, so the specification's threat model covers sandbox escape, unauthorized tool calls, data leaks and phishing. Sandboxing and content security policy limit what an app can reach, and hosts can log, block or ask the user to approve actions. The specification does not fully solve social engineering or resource use, leaving those to host warnings and limits.
Are MCP Apps part of the MCP specification?
MCP Apps are an optional extension to MCP, not part of the core protocol. The extension uses the identifier io.modelcontextprotocol/ui, and both client and server have to declare support for it.