Begin with your shop platform and what you sell. List the payment methods you need, whether you take subscriptions, the currencies involved and how you handle refunds. Confirm that any plugin or integration is supported for your actual platform version.
Compare the whole payment workflow: checkout, order confirmation, payout reconciliation and disputes. Ask who maintains the integration and whether checkout is hosted by the payment provider or embedded in your shop. Use the provider’s test environment before taking real payments and check the process on a phone as well as a computer.
Discuss pricing with the provider using your own card mix, average order value and expected volume. Check for recurring platform charges alongside processing costs. Never post API keys, customer records or card details when asking for troubleshooting help.
What platform do you use, and which part of the checkout or reconciliation process is causing difficulty? Include an error message only after removing private information.