Add items of pay to an OPEN, CALCULATING, READY or BLOCKED run, or update items it already has, matched by externalId. Every item is a pre-calculated amount: send what you've already calculated, under a pay code. Everee sets each item's type to PAYROLL_RUN_ITEM, and dates it to the last day of the run's pay period. See Earning date. Each worker's items are combined into one payment in the run. A READY or BLOCKED run goes back to OPEN, so calculate it again.
Send up to 1,000 items at a time. Every item is checked before any is saved: if any can't be accepted, nothing is saved and the 400 response lists every failing item. See Sending many items.
To correct an item whose payment has already been paid, send correction-authorized=true. See Adding, updating and correcting items for what happens to an externalId Everee has seen before.