What breaks when two systems sync
Read before scoping any integration. Nothing here is a bug in either system — which is precisely why nobody budgets for it.
- 01
The same thing has two different names.
A customer in the CRM and an account in the accounting system are the same company with different ids, different spellings and different addresses. Deciding how they are matched — and what happens when the match is ambiguous — is most of the work.
- 02
One system allows what the other forbids.
Blank phone numbers, a 40-character field meeting a 30-character one, a status that has no equivalent on the other side. Every one needs a decision: reject, truncate, default, or queue for a human.
- 03
The message arrives twice.
in the PDF
- 04
The messages arrive out of order.
in the PDF
- 05
One side is down and the other keeps going.
in the PDF
- 06
Somebody edits the record directly.
in the PDF
- 07
A deletion on one side means something different on the other.
in the PDF
- 08
Nobody can tell whether it is working.
in the PDF
6 more checks in the PDF
The complete checklist — every check with the reasoning under it, the closing note, and the other 12 documents — comes as one PDF.