Usage — Altair

Altair projects are generated with the altair CLI. Every command is type-checked and compile-time safe: a wrong argument is a compile error, not a runtime surprise.

Create a new project#

altair new blog
cd blog
shards install

This generates the standard layout: src/, db/, public/, the bin/altair wrapper script, plus .env and config/database.yml — so a fresh project's configuration is file-driven, not code-driven. See the Configuration guide.

Run the server#

altair server

Open http://localhost:3000 in your browser. Inside the project the CLI finds the project automatically — server, routes and the database commands work from any subdirectory, so you never need to type bin/. The project's own bin/altair launcher accepts the same commands if you prefer it.

Generate a scaffold#

The full magic — model, migration, controller, views and a resources route in one command:

altair g scaffold Post title:string body:text

Then migrate the database and start the server:

altair db:migrate
altair server

You get a working CRUD app for posts, ready to edit.

Generate individual pieces#

altair g model Person name:string age:int
altair g migration add-email-to-person email:string
altair g controller People index show

List the routes#

altair routes

Database commands#

altair db:create     # create every environment database from config/database.yml
altair db:migrate    # run pending migrations
altair db:rollback   # roll back the last migration
altair db:drop       # drop databases (refuses in production without --force)
altair db:seed       # run db/seeds.cr
altair assets:precompile  # fingerprint assets/ -> public/assets/
altair jobs:work     # run background jobs
altair jobs:stats    # print job counts

Project structure#

src/            your application code
db/             migrations and db/schema.cr
public/         static assets served as-is
bin/altair      the per-project command wrapper
.env            environment settings (.env.<environment> overrides)
config/database.yml   per-environment database settings

Try the demo#

The repository ships examples/hello_world, the always-running demo app:

cd examples/hello_world
shards install
crystal run src/hello_world.cr

examples/blog is the persistence demo — posts and comments survive restarts.