Posted on Aug 2

My First Dive into Real Payments Integration (with Paystack and Webhooks)

This week, I did something that felt both exciting and intimidating. I integrated a payment gateway into one of my backend APIs for the very first time, even if it was just in test mode. 🙈💳

Now, I’ve created APIs before, like user authentication, CRUD operations, and more. But this time? I wanted my API to handle actual payments and that felt like stepping into a new territory.

☺️ Why I Took This On

I’ve been working on an API where learners can register for a course track. I already had the backend logic for signing up, viewing courses, and assigning users to tracks. But I had to take it a step further:

What if learners could also pay and automatically get an invoice confirmation?

So I jumped into payment processing for the first time with no real business setup, just the test mode that Paystack provides to simulate real-life transactions.

🔄 Here’s What I Built

Invoice Generation: When a learner is about to pay for a course, the backend creates an invoice showing the amount, due date, Paystack payment link , and learner info.
Verify Payment Endpoint: I created a /verify-payment endpoint to verify if a transaction is real. This uses the Paystack verification API to confirm that the payment went through. This helped me ensure the payment wasn’t faked or interrupted.
Webhook Integration: This was the exciting part. I set up a /webhook route to receive notifications from Paystack.

🤔 Wait… What’s a Webhook?

Let me explain it the way I finally got it:

Imagine you order food from a restaurant (you = your backend app). You don’t want to keep calling them to ask, "Is the food ready yet?"

Instead, you tell them: “Here’s my number. Just call me when the food is ready.”

That call is the webhook.

In my case, Paystack is the restaurant. After the payment, it sends a POST request to my backend automatically, containing details of the transaction.

That way, even if a user closes their browser or their internet drops, my backend still gets notified when a payment succeeds and I don’t have to keep asking their API whether the transaction went through.

I made sure that the webhook was idempotent (fancy word for: “Don’t repeat yourself”).
Even if Paystack sends the same webhook multiple times, my backend only updates the invoice once.

👩🏽‍💻 Lessons I Learned

Test mode is a lifesaver. You can simulate payments without using real money.
Payment processing isn’t as scary as it sounds once you break it down.
Webhooks are super useful when you don’t want to poll third-party APIs.
Security matters cause I had to validate incoming webhook signatures to avoid spoofing.

I’m still early in my journey as a backend developer, but this week felt like a level-up, seeing my app respond to real-world actions like a payment, and handle them intelligently.