“If you're building a fully custom checkout using payment providers' APIs and SDKs, I'd put Stripe at the top of the shortlist, with Adyen, Checkout.com, Braintree, and Mollie as serious alternatives.”
“Excellent API consistency and documentation.”
“First-class SDKs, especially TypeScript/Node.js.”
“Excellent webhook testing and debugging with Stripe CLI.”
“Great sandbox and test-card support.”
“The ecosystem is particularly mature.”
“Adyen would be my second if international coverage and enterprise-scale processing mattered.”
“Sophisticated APIs and extensive payment-method coverage.”
“Strong support for global acquiring and local payment methods.”
“Good SDK coverage and API Explorer.”
“Strong omnichannel capabilities.”
“More complex onboarding and integration architecture than Stripe.”
“with Adyen, Checkout.com, Braintree, and Mollie as serious alternatives”
“Modern API architecture.”
“Good JavaScript integration experience.”
“Flow offers a customizable payment UI.”
“Good support for 3DS and asynchronous payment methods.”
“Mollie would be my alternative if the business were primarily European.”
“Straightforward REST API.”
“Good documentation and popular-language SDKs.”
“Strong European payment-method coverage.”
“with Mollie performing particularly well on accessibility and documentation.”
“Mollie Components (noting that Components is currently beta and has some limitations, including test-mode support)”
“with Adyen, Checkout.com, Braintree, and Mollie as serious alternatives”
“Established client and server SDKs.”
“Supports card payments and PayPal.”
“Supports vaulted payment methods.”
“Developer experience feels less cohesive than Stripe's modern ecosystem.”