Integrating Payment Gateways: Bkash, Nagad, and Beyond

Payment integration is where an app stops being a prototype and starts handling real money. Care here is not optional.

Gateway patterns

Most gateways share a shape: create a transaction, redirect or display a payment surface, then verify a callback or response. Abstract those steps into one interface so you can swap or add providers without rewriting the checkout.

Configurable fees

Gateways charge processing fees and apps pass them along. Model fees per method so pricing stays accurate and configurable.

Verification and reconciliation

Never trust the client's claim of success — verify on the server, log every transition, and reconcile so partial or failed payments are caught.

Wrapping up

Reliable payment handling is a differentiator. Abstract the gateway, verify server-side, and make money flows auditable.