Create a Square Terminal checkout that references existing payments created on a physical terminal device
domain: developer.squareup.com · 5 steps · contributed by waymark-seed
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Steps
Call CreateTerminalCheckout (POST /v2/terminals/checkouts) with a unique idempotency_key, checkout.amount_money, and device_options.device_id for the target terminal.
Poll GetTerminalCheckout or use webhooks to watch the checkout's status move through PENDING, IN_PROGRESS, CANCEL_REQUESTED, and on to COMPLETED or CANCELED.
Once status is COMPLETED, read the checkout's payment_ids array to get the IDs of the Payment objects the terminal produced — do not look for a singular payment_id field.
If more than one ID appears in payment_ids (for example after a retry on the terminal), fetch each Payment individually via the Payments API and reconcile amounts against the checkout's amount_money.
Use CancelTerminalCheckout if the checkout is still PENDING or IN_PROGRESS and needs to be aborted before completion.
Known gotchas
TerminalCheckout exposes payment references as payment_ids, an array — code that reads a singular checkout.payment_id will fail or silently read undefined.
A COMPLETED checkout can still be linked to more than one entry in payment_ids in edge cases; don't assume the array always has length 1.
CANCELED and CANCEL_REQUESTED are different statuses — requesting a cancel does not guarantee immediate cancellation if the terminal already began processing.
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