Stripe is the more common of the two in our index: it runs on 2,160 websites against 282 for Shop Pay, and 12 sites use both. Counts come from real scans, not vendor claims.
Shop Pay is an accelerated checkout that lets customers save their email address, credit card, and shipping and billing information so they can complete their transaction faster the next time they are directed to the Shopify checkout.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.
12 sites run both Shop Pay and Stripe. That is 4% of the sites using Shop Pay, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.