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Fastagent · open source

Your coding agent builds it. Your cloud runs it.

Describe the chat agent you want to your coding agent. It sets the app up, runs it on your machine, shows you exactly what will be uploaded, and deploys to your own cloud once you say yes.

GitHub ↗
Works with your coding agent
…or any agent that can run a terminal.
From idea to a private chat APIReal output · example app
You, in Claude Code

Help me build a headless chat agent using Fastagent.

Agent idea: a support bot that answers questions about our return policy and looks up order status.

…ask before real deployment or paid model calls.

Your coding agent runs
Dry run: cloudrun/support-bot
16 staged files (57016 bytes); staging removed after validation.
No provider operations performed.
Deployment is billable; TLS Redis is user-owned.
Command output captured from a fresh example app. No real token or key shown.Deploy URL is illustrative.

Who it's for

For builders who want the agent, not the server work.

You use a coding agent like Claude Code, Codex, Grok or Pi, and you want a chat agent that your own website, app or bot can talk to. Here is what people build with it.

Agent idea

A support bot that answers questions about our return policy and looks up order status.

Start with this idea already filled in.

Why teams use it

Your agent, on your terms.

You stay in control

Your agent lives in your own cloud account, with your own keys. Your data stays yours, and so does the bill.

Make it yours

Say what your agent should do and what it can help with. Everything else is taken care of, so you can focus on the idea, not the setup.

Safe from surprises

Only people you approve can use it, so strangers can never run up your costs.

Easy for your coding agent

Every step is safe to repeat, and every problem comes with a plain fix, so nothing gets stuck.

Straight answers

What it does, and what it doesn't.

It does
  • ✓Give you a private HTTPS address your apps can send messages to
  • ✓Stream replies and remember each conversation
  • ✓Deploy to Google Cloud Run, verified live
  • ✓Deploy to Railway, supported but not yet verified live
It doesn't
  • ✕Come with a chat website. It's an API for your own app
  • ✕Log in individual users. One token covers the whole app
  • ✕Write code or run commands. It's a chat agent, not a coding sandbox
  • ✕Pay for your cloud or model usage. Those bills are yours

Paste one prompt. Ship a chat agent.

Copy the starter prompt into Claude Code or Codex and describe your idea. Free and open source under Apache 2.0.

Read the docs ↗