# backend/src/core/

## Files

| File | What | When to read |
| ---- | ---- | ------------ |
| `README.md` | Core module index with code examples | Understanding core infrastructure |

## Subdirectories

| Directory | What | When to read |
| --------- | ---- | ------------ |
| `auth/` | Authentication utilities | JWT handling, user context |
| `config/` | Configuration loading (env, database, redis) and feature tier gating (fuelLog.receiptScan, document.scanMaintenanceSchedule, vehicle.vinDecode) | Environment setup, connection pools, tier requirements |
| `logging/` | Winston structured logging | Log configuration, debugging |
| `middleware/` | Fastify middleware | Request processing, user extraction |
| `plugins/` | Fastify plugins (auth, error, logging, tier guard) | Plugin registration, hooks, tier gating |
| `scheduler/` | Job scheduling infrastructure | Scheduled tasks, cron jobs |
| `storage/` | Storage abstraction and adapters | File storage, S3/filesystem |
| `user-preferences/` | User preferences data and migrations | User settings storage |