Payment service provider (PSP)
The vendor that plugs card payments into your site: it takes the card, gets the bank's yes or no, and moves the money into your account.
See it
What it is
A payment service provider is the vendor that bundles the pieces card money needs: the gateway that carries the card data, the processing that talks to the networks, and usually the merchant account that receives the funds. Stripe, Adyen, Braintree, Mollie, and Razorpay are PSPs. One signup, one API, one dashboard, instead of three separate contracts with a gateway, a processor, and an acquiring bank.
Reach for one the moment you want to charge cards and still be the company on the receipt. You stay the seller: your name is on the statement, your business owes the sales tax, and disputes come to you. That is exactly the trade a merchant of record takes off your hands for a bigger cut.
Gotcha: most modern PSPs put you on an aggregated account, which is why onboarding takes minutes and also why a risk review can pause your payouts with no warning. Watch the boring numbers too: payout delay (often T+2), the flat rate versus interchange-plus, cross-border and currency-conversion surcharges, and whether the saved cards can be exported if you ever switch.
Ask AI for it
Wire up Stripe as my payment service provider in a Next.js app: install the server SDK, create a Checkout Session on the server from a price ID, redirect the customer to it, and verify the 'checkout.session.completed' webhook against the signing secret before marking the order paid. Keep every secret key server-side, store the Stripe customer ID on my user record, make the webhook handler idempotent, and use test-mode keys with the 4242 card until launch.