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Questions before you choose a payment gateway API

Published January 2025 · James Okonkwo

Person paying with a card at a counter

Marketing pages list countries and card brands; they rarely explain how money moves after authorisation. Ask these on the first technical call.

Settlement and reporting

How long until funds settle to your merchant account? Do reporting APIs use the same transaction IDs as webhooks? Mismatches here break reconciliation scripts.

Partial capture and void windows

If you ship in instalments, confirm partial capture is supported in your currency and whether uncaptured amounts auto-expire.

Disputes and chargebacks

Which webhook fires at dispute opened vs evidence due? Can you attach documents via API or only through a portal?

Sandbox fidelity

Run one failed 3DS flow and one delayed webhook in sandbox. If behaviour diverges from the PDF, note it before contract signature.

Vendor API due diligence includes a scored comparison across your shortlist.