Code structure

The following overview should not be seen as complete or authoritative, but as a rough guidance to help you find your way in the application.

app/controllers: Code that binds business logic to templates
app/helpers: Code that can be used from views, i.e. common operations
app/lib: Code that doesn’t fit in the other categories
app/models: Representation of data entities and their associated methods
app/policies: Permission checks and other validations, before calling related methods
app/serializers: Code that generates JSON from models
app/services: Complex logical operations involving multiple models
app/views: Templates for generating HTML or other output
app/workers: Code that executes outside the request-response cycle
spec: Automated test suite

config/locales: Server-side localizations in the YML format
app/javascript/mastodon/locales: Client-side localizations in the JSON format

All locale files are normalized to ensure consistent formatting and key order, which minimizes changesets in version control.