Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.

Pilgrim SDK by Foursquare - Location data to understand & engage with your customers

Bonsai - One platform to streamline your entire business

Stripe iOS SDK - Accept both Apple Pay and credit card payments easily on iOS

Payzo - Accept credit cards with zero coding (for freelancers)

MightySignal Top SDKs - Most used SDKs in top 200 free iOS apps. Learn what to use.