# Developer Documentation

Guides for adding to Shelfmark.

- [Release Sources Plugin Guide](release-sources-plugin-guide.md): add a source that searches for releases and a handler that downloads them
- [Plugin Settings Guide](plugin-settings.md): add settings tabs and fields for a plugin to the Settings UI
- [Adding Routes](routes.md): where a new API route goes, and how a route module gets what it needs
- [Metadata Providers](../../shelfmark/metadata_providers/README.md): add a metadata provider