Build and test software
Ship the change,
not the checklist.
The agent writes the code, runs the tests, starts the app and clicks through it in a real browser. You review a working change, with a recording of how it got there.
You asked
Build a small to-do list web app, run it, then click through it in a real browser to check adding, ticking off and deleting items all work. Show me the result.
- Describe the changePaste the issue, point at the repository and say what done looks like.
- It works on its own machineThe agent clones, installs, edits, and runs the tests in a terminal on its own computer, not yours.
- It checks the result like a personIt opens the app in a real browser, clicks through the flow and fixes what it finds.
- You review and mergeRead the diff, watch the replay, or take the keyboard and try it yourself.
- Done. Changes that already ran.
Before and after.
The same work, handed to an agent with a computer of its own.
Today
- A small fix still means pulling the branch, installing, running and clicking through it yourself.
- Coding assistants write code they never run, so you find out it's broken after you merge.
- Your laptop is busy with one task at a time.
With FullsendAI
- Changes that already ran. Every change was executed and checked in a browser before you saw it.
- Several tasks at once. Give each task its own box and let them run side by side.
- Your machine stays yours. Installs, builds and test runs happen in an isolated box.
Start from a real task.
Each one opens the chat with the task filled in. Change the details and send.
- Build a small to-do list web app, run it, then click through it in a real browser to check adding, ticking off and deleting items all work. Show me the result.
- Clone https://github.com/you/your repo, run the tests, fix whatever fails and open a pull request with the fix.
- Add a dark mode toggle to the settings page of my app, then click through every page to check nothing breaks.
- Upgrade this project to the latest Next.js, run the build and the tests, and list anything you had to change.
What it costs.
Box time by the second while it runs, plus the AI it uses, from one balance.
Computer time for a two-hour feature, built and tested
$0.16 – $0.26
About 2 hours on a small computer, depending on where it runs. AI tokens are extra and depend on the model.
See pricingQuestions.
Before you hand it off.
Yes. The agent can clone public repositories, and private ones with a token you give it for that workspace. Everything it does stays in the workspace's box.
Any model we serve, switchable mid-chat, on one key. Use a strong reasoning model for the plan and a fast one for routine edits.
Yes. The same key works in Claude Code, Codex and Cursor; the box adds what those tools lack: a machine to run and check the work on.
Hand off the first task.
Add a card or credit to start. You only pay while your agent works.
Get started