plain definitions

The small-cloud glossary.

The words we use, defined the way we mean them.

Agent-native: Built so an AI agent is a first-class author, not an afterthought. fuast publishes its entire app contract at /llms.txt so you can tell your AI "build us a leave tracker" and it writes a working capsule on the first try. Agent-native means the contract is small, strict, and documented for a model, not a blank Linux box a human has to configure.
Batteries-included: Auth, a database, file storage, scheduled jobs, transactional email, and secrets are part of the platform, not things you provision. In a batteries-included cloud you import fuast/server and use them. See the batteries a small app needs.
Capsule: The unit of software on fuast: one small full-stack TypeScript app. A server/ half (schema, queries, mutations, endpoints) and a client/ half (a Preact UI), with a deliberately tiny import surface so it is easy to reason about and easy for an AI to write. Read capsules explained.
Endpoint: An HTTP route a capsule exposes for the outside world, like a webhook receiver. Defined in the capsule's server/ with endpoint({ method, path }, handler). Distinct from a mutation, which the app's own UI calls.
Internal tool: Software a team builds for itself rather than to sell: approvals, trackers, forms, dashboards. Historically these needed a platform team or a seat-priced builder. fuast is a way to run them as small software. See internal tools without a platform team.
Isolate (V8 isolate): A separate JavaScript execution context with its own memory, provided by the V8 engine. fuast runs every capsule inside an isolate, out of process, so one app can never read another's data or the host's secrets. It is how a shared cloud runs many teams' code safely. See how fuast runs little apps safely.
Mutation / query: The two ways a capsule talks to its database. A query reads and a mutation writes; both receive a ctx with the database and the verified signed-in user (ctx.auth). The client calls them by name. This split keeps reads cacheable and writes explicit.
Schedule: A cron function a capsule runs on a clock, written as schedule("0 9 * * *", handler). Used for a daily digest, a reminder, a cleanup. fuast runs it for you; there is no separate cron service to stand up.
Share like a doc: The core interaction of fuast: you deploy an app and send a link, exactly like sharing a Google Doc. Coworkers open it, sign in with their own account, and the app sees verified identities. Private, workspace-wide, or public. Read share software like a doc.
Small cloud: A cloud scoped to small software instead of general-purpose infrastructure. Batteries-included, agent-native, one command to deploy. The opposite of assembling auth plus a database plus hosting yourself for a 200-line app. Read what is a small cloud.
Small software: The apps that live between a spreadsheet and a real SaaS product: the little tool a team actually needs but nobody wants to build from scratch. An expense approval, a signature request, an on-call rotation. Small software needs a small cloud to run on. Read small software, defined.
Subdomain isolation: Serving each deployed app on its own subdomain (your-app.fuast.com), a separate web origin from the dashboard. Because the origin differs, an app's JavaScript cannot use your session to call account APIs. It is browser-level isolation on top of the isolate that runs the server code.
Workspace: Your team on fuast. Apps can be shared workspace-wide so every coworker who signs in can open them, and people you invite by email join the workspace when they accept.