Integrating Payment Gateways Securely: Lessons from Paymob and Stripe | Union Solutions

Payment integration is not just an API call; it is a security responsibility. Rule one: never touch card data — use hosted payment pages or tokens. Rule two: always verify webhooks via signature before updating order status. Common mistakes include trusting the browser response instead of the webhook to confirm payment, and failing to handle duplicate charges (idempotency). In our systems, we build a unified adapter layer so switching or adding a gateway becomes a config change, not a rewrite.