An integration is easy to demo and hard to trust. Two systems trade a record on stage, everyone nods, and the real problems start weeks later.

Most integrations fail on direction. When two systems both think they own the customer record, they overwrite each other, and the last write wins regardless of which one was right. The symptom shows up in a report that no longer adds up.

We fix this by deciding, per field, which system is the source of truth. Data flows one way from there. Everything else reads, it does not write.

The second fix is visibility. Every sync logs what it moved and what it skipped, so when something looks wrong you can see why in minutes instead of guessing for days.