Two-way sync
Also known as: bidirectional sync · two-way integration
Definition
An integration pattern in which two systems exchange data in both directions: changes made in system A propagate to system B, and changes made in system B propagate back to system A. Requires explicit conflict handling and a notion of authoritative fields per direction.
Why it matters for HRIS ↔ payroll sync
HRIS ↔ payroll is a textbook two-way-sync problem: master data flows from HRIS to payroll, payslips and sick-leave certificates flow the other way, and a handful of fields (tax class, social-security number) genuinely live on the payroll side. A naive one-way push overwrites changes the payroll team makes; a naive one-way pull misses HR updates. stoa treats each field as an authoritative-side declaration, runs a diff before every cycle and lets the operator approve or reject changes.