Third-Party API Integrations

Most modern web apps are orchestration layers that glue third-party services together. This category is the practical integration cookbook for the APIs Indian applications most often depend on: Razorpay and Stripe payments (with webhook signature verification done right), WhatsApp Business API onboarding, SMS OTP via MSG91 and Twilio, transactional email through SMTP, SendGrid, and Amazon SES, OAuth 2.0 social login, and general webhook handling patterns. Each guide includes working code in PHP and Node.js, a common-pitfalls section, and a go-live checklist. For the security foundations these integrations depend on (HMAC signatures, timing-safe comparison), see our Web Application Security category. Most articles assume basic comfort with API calls from your backend.