Keyboard shortcuts

Press or to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Language overview

Atlantus apps are multi-file .atl modules under app/. The CLI compiles them and the runtime serves HTTP routes.

What you write

  • Functions and route handlers in .atl
  • JSON-friendly values: numbers, strings, bools, arrays, maps
  • Null checks with none
  • Modules with import

Types (practical)

TypeNotes
Int, Float, Bool, StringScalars
Arrays / listsOrdered values
Maps / { "k": v }JSON objects
Request / ResponseInferred at the HTTP boundary

Day to day, rely on atlantus check for type and arity errors.

Modules

module users

import services.users as Users

Paths under app/ map to import paths. Prefer matching the scaffold’s style.

Built-ins

HTTP, request, DB, auth, and jobs helpers are built into the runtime.
See Built-in API.

Dev vs production

CommandTypical use
atlantus devFast compile, great DX, optional --watch
atlantus startProduction-shaped process

You write the same .atl either way.

How it runs (optional)

Internally the toolchain compiles to bytecode (and may AOT hot paths). You do not configure compiler crates as an app author — install atlantus and focus on .atl.

Next: HTTP & JSON.