Delta Events

Each time Catalogian checks a source, it produces a delta event. If nothing changed, it's recorded as a no-change event. If rows were added, modified, or removed, you get exact counts and the affected keys.

Delta event fields

id              string    unique event ID
detectedAt      ISO 8601  when the check ran
newCount        int       rows added
changedCount    int       rows modified
deletedCount    int       rows removed
unchangedCount  int       rows that didn't change
totalCount      int       total rows in snapshot
isNoChange      bool      true if nothing changed
newKeys         string[]  up to 100 added row keys
changedKeys     string[]  up to 100 changed row keys
deletedKeys     string[]  up to 100 deleted row keys

Full changed row data (before/after values) is available via the delta rows endpoint. See Row Diffs →

Retention

Use cases

• •Webhook triggers — push changes to downstream systems the moment they're detected
• •Downstream sync — keep databases, search indexes, or marketplaces in sync
• •Audit trail — full history of what changed and when
• •AI agent feeds — give agents structured change data to act on