Amber CLI

Amber CLI is the standalone command-line companion for Amber V2. CLI 2.0.6 creates the supported Amber 2.0.0-beta.5 ECR web application and includes development, generator, database, and LSP tooling.

Amber V2 is a beta. The release-gated path is a web application on Apple Silicon macOS, x86_64 Linux, or ARM64 Linux. Windows x86-64 generated-app compilation is checked in CI for compatibility, but Windows does not block this beta release. See Generator support before relying on authentication, API-resource, or native output.

Install

Prerequisites: Crystal 1.20 or newer (but earlier than 2.0), shards, and Git.

Homebrew on macOS or Linux

The tap and formula names contain underscores; the installed executable is amber:

brew install amberframework/amber_cli/amber_cli
amber --version

The fully qualified command follows Homebrew's tap-trust model and trusts only the amber_cli formula.

Direct release archive

CLI 2.0.6 publishes darwin-arm64, linux-x86_64, and linux-arm64 archives. Windows x86-64 is compiled in CI but does not yet have a release archive.

version=v2.0.6
platform=darwin-arm64
asset="amber_cli-${platform}.tar.gz"

curl -fLO "https://github.com/amberframework/amber_cli/releases/download/${version}/${asset}"
curl -fLO "https://github.com/amberframework/amber_cli/releases/download/${version}/${asset}.sha256"
shasum -a 256 -c "${asset}.sha256"
tar -xzf "${asset}"
install -m 0755 amber amber-lsp /usr/local/bin/
amber --version

On Linux, use sha256sum -c for the checksum. Prefix only the install command with sudo if /usr/local/bin is not writable.

Create and verify a web app

amber new my_app --type web
cd my_app
amber assets check
crystal spec
crystal build src/my_app.cr -o bin/my_app
amber watch

amber new installs shards by default and compiles the starter assets. Pass --no-deps when an offline or CI workflow needs to run shards install later. amber watch recompiles assets before the application whenever an ECR template or a file under app/assets/ changes. Open http://127.0.0.1:3000.

The web template is deliberately small:

• Amber from amberframework/amber, pinned to 2.0.0-beta.5
• ECR views (Slang and Kilt are not supported in Amber V2)
• typed development, test, and production YAML
• branded homepage, controller spec, and fingerprinted CSS, JavaScript, SVG, font, image, and general static-file support
• a browser-native import map with a local JavaScript module entry point
• Grant ORM, Micrate-powered migration commands, and the selected database driver
• SQLite by default, so the first persisted feature needs no database server

The -d pg|mysql|sqlite option selects the generated driver, connection, and development/test URLs. SQLite is the default; PostgreSQL and MySQL expect their respective local servers or a DATABASE_URL.

Static assets: source versus generated output

Write application-owned files in these directories:

app/assets/
├── stylesheets/  # CSS; starter entry: app.css
├── javascript/   # browser modules; starter entry: app.js
├── images/       # SVG, PNG, JPEG, WebP, AVIF, and icons
├── fonts/        # WOFF, WOFF2, TTF, and OTF
└── files/        # PDFs, web manifests, and other downloads

Run the compiler after an authored asset changes outside watch mode:

amber assets build
amber assets check

The build fingerprints every file into public/assets/, rewrites local CSS and JavaScript references, writes SRI and response metadata to public/assets/manifest.json, and creates deterministic gzip siblings for compressible files. public/assets/ is generated and gitignored; do not edit or commit it. Keep stable root files such as public/robots.txt in public/.

In src/views/layouts/application.ecr, resolve authored logical names through stylesheet_link_tag, javascript_importmap_tag, image_tag, and favicon_tag. In CSS, references are relative to that CSS source file; for example, app/assets/stylesheets/app.css uses url("../images/amber-crystal.svg"). The compiler replaces that reference with the image's fingerprinted URL.

Create the first complete resource and its database table:

amber generate scaffold Pet name:string:required species:string:required adopted:bool
amber database migrate
amber watch

The generator writes the Grant model to src/models/pet.cr, the request schema to src/schemas/pet_schema.cr, the controller to src/controllers/pet_controller.cr, ECR views to src/views/pet/, a Micrate SQL migration to db/migrations/, and the resource route to config/routes.cr.

Commands

Command	Status	Purpose
amber new APP --type web	Supported	Create the beta web application
amber watch	Supported	Rebuild and restart during development
amber routes	Supported	Inspect application routes
amber pipelines	Supported	Inspect configured pipelines
amber generate	Mixed	Model, scaffold, migration, and core generators supported; auth and API preview
amber database	Supported	Apply, roll back, inspect, redo, and seed the generated database
amber assets build	Supported	Fingerprint app/assets/ into generated public/assets/ output
amber assets check	Supported	Verify manifest, bytes, integrity, MIME, and compressed output without changing it
amber new APP --type native	Preview	Not part of the beta platform guarantee
amber setup:lsp	Available	Configure the bundled diagnostics LSP

Run amber --help or amber COMMAND --help for command syntax. The detailed web-app walkthrough and generator table define what is release-gated.

Update and troubleshoot

brew update
brew upgrade amber_cli
type -a amber
amber --version

If an older Amber V1 executable appears first, remove or rename it or put the new installation directory earlier in PATH. On macOS, include otool -L "$(command -v amber)" in install bug reports; release binaries must not require the retired openssl@1.1 library.

Report CLI, template, or binary problems at https://github.com/amberframework/amber_cli/issues. Include OS/architecture, crystal --version, amber --version, install method, command, and complete output.

LSP

The release archive includes amber-lsp. From an Amber project:

amber setup:lsp

See the LSP setup guide.

Contributing

shards install
crystal tool format --check src spec
crystal spec

See CONTRIBUTING.md for the project workflow.