# Change detection

Running a program on a schedule and being told only when the fields you care about change.

A schedule with change detection compares each run's data with the last run's, field by field, and sends a schedule.changed event with the difference. Unchanged runs stay quiet.

```
kaab schedules create --program acme-report@production \
  --cron "0 * * * *" --change-detection --field price
```

## Related

- [Sessions and schedules](/product/sessions-and-schedules)
- [Monitor pages behind a login](/use-cases/monitor-behind-login)
- [Browser session](/glossary/browser-session)
- [Webhook signature](/glossary/webhook-signature)