MCP apps are the new website: they're real, interactive apps that run right inside AI assistants like ChatGPT and Claude. The tooling to build them didn't exist, so we built it. Meet Skybridge, the React framework that handles the infrastructure and the dev loop so you can focus on your features: MCP server, view rendering, client compatibility, testing tunnel, and more. Code once, ship everywhere. Already +500K downloads and dozens of apps in the stores!
The local emulator with hot reload is the part that stands out to me, the rebuild and reconnect loop for MCP apps has been rough. Does the tunnel handle auth flows when testing against Claude, or is that still manual? Congrats on shipping.
Skybridge
Hi @i_sanjay_gautam, thanks! Glad the hot-reload loop hits home, that was exactly the pain we set out to kill. On auth, Skybridge does most of the work: it auto-adapts the OAuth metadata to the public URL (the server infers the resource origin from forwarded headers), and discovery + JWKS verification are automatic, so testing against Claude just works. The only manual bit is registering the tunnel URL as a connector and enabling DCR in your IdP. Happy to share the exact setup if useful!
Bitmovin
Congrats Alpic and Skybridge team! We are a super happy user of Skybridge. Our MCP Apps are powered by Skybridge; it really helped us with the dev effort and to make it compatible and ready to launch in the ChatGPT and Claude App Stores.
I think MCP Apps will be a necessity for news, media, and entertainment, sports, etc. in the future. I'm excited to see what companies will do there. Do you already see cool apps in this area out there? what are the interesting features or what are the issues that you see?
Skybridge
@slederer Thanks for the kind words, Stefan :)
Here are a few apps that showcases interesting MCP Apps features :
- Murder in the Valley : An investigation game that showcase model-side vs. user-side knowledge asymmetry
- Chess App : A chess app that features the new capability of providing tools directly from the UI and letting the agent call them
- Alpix : A game inspired by Pixel War that shows how to share realtime content (here, a canvas) between multiple users interacting with the MCP App together
Excellent lancement ! Le cadrage « MCP apps = nouvelle UI » est très juste, et la DevTools locale règle exactement la douleur que je vivais (la boucle rebuild/reconnect était insupportable). Petite question : quand on passe en prod, le tunnel de test laisse place à quel mode de déploiement recommandé pour un serveur MCP auto-hébergé ? Bravo à l'équipe 🚀
Skybridge
@victor_peltier merci pour le soutient, ca fait super plaisir :) !
En ce qui concerne le déploiement, un packaging Docker reste l'option la plus flexible. Un dockerfile est inclus avec le lancement d'un nouveau projet Skybridge pour permettre de déployer sans avoir à se casser la tête sur ce sujet là. On fournit aussi des options de déploiements vers Cloudflare et Vercel si ca matche ta stack. N'hésite pas si tu trouves pas chaussure à ton pied et qu'il faut qu'on rajouter de nouvelles options de déploiements sur Skybridge
@fredisterik au top merci !
Skybridge
Hey @konstant_gk , thanks for your message :)!
Just to make sure I understood correctly, you mean ChatGPT underlying API, or Claude underlying API powering this kind of new surface?
If that's the case, the API is documented and local only: MCP app interact with their host using iFrame post messages on Claude, and global window property on ChatGPT. Those API are synchronous, provided by the browser (that act as the interface layer) and do not require them to be based on webhook or pooling mechanism.
If not, let me know which API you were referencing instead here :)
@fredisterik Oh ok great. Yes that's what I was referring too. Thanks for the clarification!
Skybridge
@konstant_gk glad to hear I understood your question correctly :) The API feels a bit uncommon, but it’s what powered the Facebook marketplace app back in the days too. Nothing new under the sun here, except the addition of an LLM in the mix. This makes the overall MCP app experience much more powerful than what you could do with Facebook apps back in the days ;)
The host-quirk problem is real. If MCP apps become a normal surface, the framework value is less "React for agents" and more a reliable dev loop: emulator, tunnel, compatibility, and tests that keep each host from becoming bespoke work.
Skybridge
@krekeltronics thanks for pointing that out. We aim at keeping Skybridge as the agnostic interface layer in front of all host specific implementations (like view state that is implemented completely differently on ChatGPT and on Claude). You can always access the underlying API when you need to implement host-specific feature, but for the general feature set, we got you covered ;)
Congrats on the launch ! Question from the document-infra side: how does Skybridge handle rendering for heavier components like a document or PDF viewer vs lighter interactive UI?
Skybridge
@benjouss Hey Benjamin, thanks for your support :)
Basically, Skybridge uses React under the hood for component rendering, so it works even for heavy apps like PDF viewers.
Worth noting: chat assistants like Claude and ChatGPT heavily cache your app's assets, so after the first render, the app is very quick to load again.
@julienvallini Makes sense, thanks ! Though the caching is the app code itself, right? For a multi-MB PDF loaded at runtime, is there a payload ceiling across hosts, or is that on the dev to stream/chunk?
Skybridge
@benjouss Good distinction. What the host caches is the initial HTML file, the one containing the link to your source code. From there, your source code uses whatever cache your hosting solution provides.
There's no host-imposed payload ceiling on it. The app runs in a sandboxed iframe and behaves like a regular JS app, so streaming or chunking a heavy payload is on the developer side, just like you'd do in a normal SPA.
Let me know if you want more detail :)
@julienvallini Thanks for the clarity. Good to know there's no host-imposed ceiling so streaming stays in the developer's hands. Clean architecture. Will be keeping an eye on where you take this :)
Very nice, thanks for sharing! I didn’t see before the existence of an app store on ChatGPT. How long does it take for an app to be accepted upon submission ?
Skybridge
Hey @pierre_milliotte1 , very grateful for your support :)
For ChatGPT it usually takes 1 to 5 days (we've noticed it's been a bit faster recently). For Claude, though, even though the submission form is open, it's unlikely your app will make it into the store unless you're already in a partnership with Anthropic.
That will probably change in the future, given how fast-moving the space is.
Skybridge
@pierre_milliotte1 On chatGPT it now can take up to 2 weeks, on Claude it's still a lot slower
Skybridge
@pierre_milliotte1 It's getting faster now, less than a week if you did everything properly. You can pass your MCP on beacon.mcp.alpic to check everything works well before submission.
It's way longer on Claude at the moment