documentation/content/en/dev/code.md

---

title: Code structure description: Where to find certain parts of the codebase. menu: docs:

weight: 30
parent: dev

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Code structure {#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.

Ruby {#ruby}

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

JavaScript {#javascript}

app/javascript/mastodon : Code for the frontend React.js application

app/javascript/packs : Code for non-React.js pages

CSS and other assets {#assets}

app/javascript/images : Images

app/javascript/styles : Code that turns into CSS via Sass

Localizations {#localizations}

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.

• Run bundle exec i18n-tasks normalize to normalize server-side translations
• Run yarn run i18n:extract to extract and normalize client-side translations into en.json