When a payments platform grows from a few thousand merchants to millions, the architecture that got you there is usually the thing holding you back. We saw this first-hand while building a Swipe Chargebacks System for a leading Indian fintech processing over 10 billion transactions a year.
Here's what we learned moving from a tightly coupled monolith to a modular microservices architecture.
The symptoms of an outgrown monolith
A monolith isn't inherently bad — plenty of successful products run on one. The trouble starts when different parts of the system need to scale, deploy and fail independently, but can't. The tell-tale signs we saw:
- Scaling was all-or-nothing. A spike in one workflow forced us to scale the entire application.
- Reconciliation needed constant manual intervention. Failed transactions piled up and delayed settlement.
- Upgrades were risky. Tightly coupled components meant a small change could ripple everywhere.
What we changed
We decomposed the system into independent, loosely coupled services — a dedicated chargeback service, a notification service, and more — each owning its data and deployable on its own. Around them we built:
- Automated reconciliation to remove the manual error-handling bottleneck.
- Real-time analytics dashboards so operations teams had live visibility.
- A CI/CD pipeline for fast, reliable deployments.
- Scalable AWS infrastructure designed to absorb growth.
When microservices are (and aren't) worth it
Microservices trade simplicity for independence. Only make that trade when the independence actually buys you something.
If your team is small and your product is still finding its shape, a well-built monolith will serve you better. Reach for microservices when you have distinct workloads that genuinely need to scale and deploy separately — and when you have the DevOps maturity to operate them.
For a payments platform at this scale, the trade was clearly worth it: faster payments, far less manual work, and a platform that's now easy to extend.
If you're weighing a similar move, talk to us — we're happy to share what we'd do in your situation.