fuast vs Bolt

Bolt.new is impressive: it builds and runs a full-stack app right in your browser using WebContainers, so you prompt, see it run, and iterate without touching a terminal. For rapid prototyping and experiments, it is a genuinely fun, fast loop. fuast is aimed at what happens after the prototype works: a place the tool lives, and your team signs in and uses it.

The core difference: a dev environment vs a place the tool lives

Bolt runs your app inside the browser tab. That is the clever trick and also the boundary. A WebContainer is a development sandbox: great for building and seeing an app come to life, not a home where a tool runs for months while your finance team files expenses through it. To take a Bolt project to production you export it and go deploy it somewhere, with real auth and a real database, the usual way.

fuast is that somewhere, built in. A fuast app is a capsule: one small full-stack TypeScript file set. fuast deploy puts it on a cloud where auth, a database, file storage, cron, and email already exist. The app runs server-side on its own subdomain origin, not in a tab, so it keeps running and keeps its data whether or not anyone has it open.

Managed auth, data, and sharing vs export-and-figure-it-out

The prototype is the easy 80%. The last mile - who can open this, where the data lives, how five coworkers use it at once - is the part that decides whether a tool ships. Bolt gets you a working project; that last mile is yours to arrange after export.

On fuast the last mile is the platform:

• Auth is verified. ctx.auth.userId is confirmed by the platform, never trusted from the client.
• Data is managed. ctx.db.<table> is a real, persistent database. No connection string, no migrations to run by hand.
• Sharing is one motion. Deploy, get a link, and share it like a doc. Coworkers sign in with their own account; the app sees who they are. Private, workspace-wide, or public.

Where Bolt is the better call

Honestly, Bolt wins in a few real situations.

• In-browser experimentation. Nothing to install, nothing to deploy, instant run. For sketching an idea or a quick demo, that immediacy is hard to beat.
• Full framework and npm freedom. Bolt runs a real Node environment in the tab, so you can pull any package. fuast runs a small, strict contract on purpose - no npm, no Node builtins - which is the tradeoff that makes it safe to run multi-tenant and reliable for an AI to write first try.
• Learning and throwaway builds. When the point is to tinker and you will never ship it, a browser sandbox is exactly right.

If you are prototyping and experimenting, Bolt is a great environment. fuast is not trying to be a browser IDE.

Where fuast wins

• The tool actually lives somewhere. A live URL, running server-side, with persistent data, not a project you have to export and re-home.
• Batteries included. Auth, database, storage, cron, and email are the platform, not an assembly step after export.
• Your team signs in. Share like a doc, verified identity, no per-seat wall.
• Real isolation. Each capsule runs in a V8 isolate on its own origin, so a workspace of tools stays walled off.
• Agent-native by design. The whole contract is published at /llms.txt, so your AI writes a capsule built to run, not a prototype you then productionize.

The short version

Prototype in Bolt; run it on fuast. Reach for Bolt when you want to build and experiment in the browser with no setup. Reach for fuast when the tool has to stop being an experiment: managed auth, persistent data, and a link your whole team signs into. More in AI app builders vs real apps, or compare the internal-tool builders in fuast vs Retool. Ready to make it real? Start free.