Choosing a checkout
Use a hosted page if you want the card form off your server. Use a payment link if you invoice by email. Use an integration only when an order in your own system must update itself.
Resources
Read this before you ask for a quote.
Three short notes. They do not replace the written agreement.
Preparing payouts
Have the payee’s legal name, the account you were given, and your own reference before the first batch. A mismatch should stop the line, not guess.
Going live
Run one real payment and one real payout at a small amount. Match them to your books. Then raise the limit named in the agreement.