Read this when a change crosses the browser, database, or configuration filesystem boundary.

# Integration Index

| Integration | Direction | Protocol | Implementing files | Documentation |
|---|---|---|---|---|
| Browser JSON API | Bidirectional | Same-origin HTTPS/HTTP + JSON + PHP session cookie | `ui/app/src/api/client.js`, `src/Core/Api/` | [browser-api.md](browser-api.md) |
| MySQL persistence | Outbound | PDO/MySQL via F3 `DB\SQL` | `System.php`, `User.php`, `Notifications.php`, API controllers | [mysql.md](mysql.md) |
| Encoded configuration files | Bidirectional | Local filesystem, base64+gzip INI payload | `index.php`, `RuntimeServices.php`, `AdminController.php`, generator script | [encrypted-config.md](encrypted-config.md) |

Each integration has integrity or authorization controls that must not be weakened. See the linked trust-boundary tables.