How it works
Read-only integrations copy data out. Write-back sends changes in: creating an invoice in a ledger, recording a bill payment, adjusting stock on a storefront or posting tracking numbers to a marketplace. Writes are harder than reads. They must pass the platform's validation, respect closed periods and approval rules, avoid duplicates on retry and leave a record of who changed what.
Example
An AP product reads bills from Xero, pays them, then writes the payment back so the bill shows as paid in the customer's books without a bookkeeper entering it twice.
In integrations
Finance-grade write-back is a core Unify Int pillar: idempotency keys, validation before submit, optional approvals and a full audit trail. Coverage shows read and write separately per object and per platform, and write is shown only where write-back is confirmed; otherwise the object shows Read with write on the roadmap. Write-back is usually what turns an integration from a report into a workflow. It is also where mistakes are expensive, so ask any vendor how writes are validated, retried and audited.