# Plugins

> Lettern's own features — the admin included — are modules and plugins built with the same API you get. Anything they do, yours can do.

The admin's screens are modules inside `letterncms/cms`; the builder, the static site, SEO, media, forms, email, MCP and the assistant are plugins, each a Composer package and a repository of its own. Both are the same kind of package, none uses a private API, and each can be switched off or replaced. That is the best documentation there is — read their code next to these pages.

- [Modules](https://docs.lettern.org/plugins/modules) — what the admin is made of, switching parts off, their settings and what each costs
- [How plugins work](https://docs.lettern.org/plugins/how-plugins-work) — packages, providers, lifecycle, blocks, data sources, collections
- [Your first plugin](https://docs.lettern.org/plugins/your-first-plugin) — a complete, working example
- [Hooks](https://docs.lettern.org/plugins/hooks) — every action and filter
- [Admin extensions](https://docs.lettern.org/plugins/admin-extensions) — screens, panels, block workspaces, fields, commands
- [Settings](https://docs.lettern.org/plugins/settings) — configuration screens for free

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Source: https://docs.lettern.org/plugins