# Connect our other tools

Keep a CRM, mailing platform or internal application aligned with Paydro registrations.
Start with [summary](summary.md); define the destination, event scope, fields and desired update frequency.

## Choose a connection
Check the existing HubSpot or Mailchimp organizer integration before building a custom connector.
Their provider OAuth callbacks are not a public Paydro OAuth or webhook-subscription service.
For custom synchronization, authenticate on your server and use documented reads and snapshot/change resources.

## Custom synchronization
1. Import `/orders/all_data.json` or `/{event_id}/order_lines/all_data/2.json` for the required scope.
2. Parse the documented compact shape and retain event, order, attendee and product UUID relationships.
3. Upsert destination records by stable IDs; avoid using email as the registration's unique key.
4. Poll the matching `changed_data` resource and apply `deleted_items` by ID.
5. Commit each successful local import before advancing your own synchronization state.
6. Keep ETags scoped to origin, credentials and exact URL; a 304 keeps the previous payload.
7. Recover from a missed weekly window with a fresh import and periodically reconcile a full paginated view.

## Limits
Changes start at Sunday midnight in the server timezone; there is no durable arbitrary “since” cursor.
Bulk orders have a 75,000 combined-row cap; event attendee snapshots have a 10,000-row cap.
Company attendee snapshots cover events starting within two years; use event scope for older events.
Deletion tracking is time-limited; absence from a capped snapshot is not proof of deletion.
No public webhook-subscription API is documented. Do not treat payment callbacks or stage SSE as registration webhooks.

## Verify
Exercise duplicate imports, edited answers, cancellation/deletion, a weekly rollover and recovery from downtime.
Keep personal fields minimal and preserve the destination's consent/unsubscribe state.

## More documentation
- [Synchronization](https://developer.paydro.com/en-us/docs/synchronizing-data.md)
- [Pagination and limits](https://developer.paydro.com/en-us/docs/pagination-and-filtering.md)
- [HubSpot](https://developer.paydro.com/en-us/docs/hubspot.md) / [Mailchimp](https://developer.paydro.com/en-us/docs/mailchimp.md)