Square payments development
Square online payments and marketplace fees, built alongside Stripe and kept in lockstep.
63Digital builds on Square's APIs for platforms that take payments on behalf of sellers: OAuth onboarding and token refresh, card payments with 3-D Secure through the Web Payments SDK, Apple Pay and Google Pay, application fees and payout reconciliation. Our Rebll Tickets platform runs Square alongside Stripe, with every fix applied to both providers.
What we do on Square
OAuth onboarding
Sellers connect their own Square accounts, with encrypted tokens refreshed before they expire.
Online card payments
The Web Payments SDK with 3-D Secure verification passed through, plus Apple Pay and Google Pay.
Fees & payouts
Application fees within Square's limits, actual processing fees recorded, payouts reconciled from webhooks.
Hybrid checkouts
Square card payments with a Stripe-powered buy-now-pay-later option alongside, chosen per event.
Is Square right for you?
A good fit when
- ✓Your sellers already use Square in person and want online sales in the same account
- ✓You run a platform that takes a fee on sellers' payments
Probably not when
- –You need buy-now-pay-later from Square alone (we ran Klarna through Stripe alongside Square)
Related: System integration
Common questions
Can a platform take a fee on Square payments?
Yes. Set app_fee_money on each payment made with the seller's access token. Keep it within Square's limits; we cap platform fees at 60% of the charge so it always fits.
Do Square OAuth tokens expire?
Yes. We refresh them with a daily job for any token that expires within the next 7 days, and store them encrypted.
Why does Square decline a payment after the 3-D Secure challenge succeeds?
In our case the Web Payments SDK's verification token wasn't being passed to the create-payment call. Forward it, and verified UK and EU cards go through.
Building on Square?
Tell us how your sellers get paid. We'll build the onboarding, the checkout and the reconciliation.