Give each record a source of truth
Decide which system owns customers, invoices, payment status, products and employee information. Ownership can differ by record type. For example, a sales team might maintain customer contacts in the CRM while finance controls posted invoices in its accounting application. Document the rule and the people allowed to correct exceptions.
Define direction, timing and scope
List the fields that should be exchanged, whether the transfer is one-way or two-way, and how soon an update is needed. Include currencies, tax codes, archived records and custom fields. Ask which product editions, API permissions and third-party subscriptions are required. A named integration does not mean every field or workflow is automatically included.
Plan the failure path
Consider duplicate events, expired credentials, temporary service outages and records rejected by validation. Agree how failures are surfaced, who investigates and how a retry avoids creating duplicates. Reconciliation should compare meaningful outcomes such as invoice identity and payment allocation, not just count successful requests.
Test before connecting live work
Use a controlled test environment or agreed test records where available. Confirm both the expected update and its side effects, including notifications and financial entries. Review access, logging and credential ownership, and agree how the connection can be paused if something unexpected happens.