Stripe is the default payment processing platform for UK online businesses and SaaS companies. It handles one-time payments, subscriptions, invoices, and marketplace payouts via the Connect platform. Pricing is transaction-based (1.5% + 20p for UK cards). Stripe is fully GDPR-compliant with EU data storage, PCI DSS Level 1 certified, and integrates with accounting tools like Xero and FreeAgent. Its API-first approach makes it the top choice for UK tech companies.