Stripe provides payment processing and financial infrastructure through APIs: card and local payment methods, hosted Checkout, subscriptions and usage billing, invoicing, marketplaces, tax calculation and fraud tooling. It is developer-oriented, with extensive documentation and test mode, and is priced per transaction.

Paddle sells software as the merchant of record, which means it takes on sales tax and VAT registration, invoicing, compliance and chargebacks on the seller's behalf. It covers checkout, subscriptions, dunning and revenue reporting. Fees are higher per transaction than a pure processor because the tax and compliance work is included.