2 C# templates
Build C# apps with AI
An ASP.NET Core minimal API — one file, with the whole framework behind it — built by conversation and running live in a cloud sandbox, with the .NET SDK in the terminal.
The C# templates
Start opens the New Web App dialog with the template picked — you set the stack, design, model and MCP tools there.
- ASP.NET Core
A minimal API on ASP.NET Core — one file, and the whole framework behind it.
- ASP.NET Core AI SaaSAI SaaS
An AI SaaS dashboard: landing, Supabase sign-in, AI chat with history, MCP tools and knowledge search.
Every C# project gets
- A cloud sandbox with a live preview of the running app
- A real terminal with 15 coding CLIs — Claude Code, Codex, Cursor CLI, Gemini CLI and more
- AI on your own keys from 24 providers, billed by the provider at cost
- Its own GitHub repository from the first push
Where it can go
Vercel has no .NET runtime, so ASP.NET Core is not deployed there. Push to your GitHub repository and deploy as a container or to any .NET host.
Questions
Can I build a C# app with AI?
Yes. Pick one of 2 C# templates — ASP.NET Core — and describe what you want. The builder writes the code in a cloud sandbox with a live preview and a real terminal, using your own AI provider key.
Where can I deploy a C# app built here?
Vercel has no .NET runtime, so ASP.NET Core is not deployed there. Push to your GitHub repository and deploy as a container or to any .NET host.
What happens when I press Start?
You sign up — or, if you are already signed in, go straight on — and the New Web App dialog opens with that template picked. Set the name, stack, design, model and MCP tools there, then press Create.
Do I own the code?
Yes. The project is pushed to your own GitHub repository, and you can open a terminal on it at any point.
Start your C# app
7 days free, no card. Plans from $8 a month for the sandbox — AI is billed by your provider, at cost.
Pick a template