Agree on commercial requirements.
The client and qualified advisers approve the seller, pricing, GBP or other currency display, tax inputs, invoice fields, terms and refunds.
Payment project planning
Plan what the customer and staff see after checkout.
A useful payment scope includes incomplete results and the records needed to resolve them.
Review actual provider options.
Confirm supported accounts and interfaces before promising a route. Keep displayed prices, settlement and accounting records clear.
Define incomplete results.
Distinguish pending, declined, duplicate, cancelled and refunded states. Name the person following up when provider and application records disagree.
Verify in isolation.
Use vendor test environments without real charges or customer messages. Check receipts, repeated events and reconciliation against agreed records.
Find the official tax research link or describe the checkout task.