Integrating Paystack and Ghana Mobile Money: Production Best Practices

Ghana's digital commerce runs on Mobile Money. Integrating Paystack correctly requires more than just calling the initialize endpoint. ### 1. Never Trust the Client-Side Redirect When a customer completes payment on Paystack and returns to your callback URL, the query parameter reference is merely a hint. Your backend must call Paystack's `/transaction/verify/:reference` endpoint server-side to inspect the true authorization status and exact amount received. ### 2. Cryptographic Webhook Verification Your webhook endpoint must verify the `x-paystack-signature` header using an HMAC SHA512 hash computed against the raw request body with your secret key. This prevents spoofed transaction notifications. ### 3. Idempotent Payment Handlers Because Paystack may retry webhooks if your server takes more than a few seconds to respond, your database must enforce unique constraints on transaction references to prevent double-crediting user accounts.