payment-integration

Implement payment integrations with SePay (Vietnamese payment gateway supporting VietQR, bank transfers, and cards) and Polar (global SaaS monetization platform with subscriptions, usage-based billing, and automated benefits). Use this when integrating payment processing, implementing checkout flows, managing subscriptions, handling webhooks, processing bank transfers, generating QR codes, automating benefit delivery, or building billing systems. Supports authentication (API keys, OAuth2), product management, customer portals, tax compliance (Polar as Merchant-of-Record), and comprehensive SDK integrations (Node.js, PHP, Python, Go, Laravel, Next.js).