Support

fuast is in early access. This page says what is supported today.

CLI platforms

The CLI runs on Bun 1.2 or later, on macOS (arm64, x64) and Linux (x64, arm64, glibc). Windows works through WSL. Bun runs the CLI and fuast dev. Capsule code never gets Bun, Node, or npm APIs.

Hosted apps run on Node 24 inside V8 isolates, one per app deploy. See isolation.

Browsers

App clients need JavaScript, WebSockets, fetch, and cookies. Current Chrome, Edge, Firefox, and Safari are supported. Agent tools currently work only in Chrome with the WebMCP flag.

Public API

The supported surface is what these docs describe:

• capsule(), the schema builders, handler wrappers, response helpers, and ctx from fuast/server.
• The exports of fuast/client and fuast/ui listed in capsule API.
• The database API in database.
• The CLI commands, inspection routes, HTTP call API, and storage routes in reference.

Not part of the API: the realtime wire protocol, build output layout, generated file names, internal platform routes, and error message wording. Branch on error codes and --json output, not on message text.

Compatibility

• Deploys are immutable. A running deploy keeps working when fuast ships a new CLI.
• Redeploying with a newer CLI rebuilds against the current API, and type errors block the deploy. Read the release notes and migration guide before upgrading an old capsule.
• fuast-env.d.ts must match the CLI. Run fuast types after upgrading.
• Old aliases stay: text(), httpText, uploadFile, SignInWithGoogle, isAuthenticated, and endpoint URLs under /e/.

Persistence

• Hosted app rows, files, logs, and env persist across deploys, rollbacks, and restarts.
• fuast dev keeps local rows and files in .fuast/dev. fuast dev --reset wipes them. Do not commit .fuast/.
• fuast db export writes a complete JSON backup in pages. It is not a point-in-time snapshot of a busy app.
• Archive and terminate keep data. They are not deletion requests.
• Team tables and storage quotas belong to the workspace and persist when individual apps are archived.

Getting help

• Check fuast logs and fuast inspect first. Most failures are a handler error or a limit, and both are logged with the exact message.
• Limits lists every error string with the fix.
• Report bugs and security issues to support@fuast.com. For security issues, include "security" in the subject.