The Challenge
Our client, a leading international payment processor handling over $2B in daily volume, was struggling with a legacy monolithic architecture. During Black Friday and other peak load events, database deadlocks were causing up to 2% of transactions to fail or timeout.
Their engineering velocity had also ground to a halt, taking 6 months to integrate a new regional payment gateway due to tightly coupled codebase dependencies.
The DivyamStack Solution
We deployed a dedicated team of 6 senior engineers (Architects, Backend, DevOps) to gradually strangle the monolith and migrate them to an event-driven microservices architecture.
Key Technical Decisions:
- Event Sourcing with Apache Kafka: We decoupled the transaction ingestion from the processing engine. Transactions are now rapidly ingested into a highly durable Kafka topic, ensuring that spikes in traffic are buffered rather than overwhelming the database.
- .NET Core Microservices: We broke down the monolith into domain-specific microservices (e.g., Auth, Ingestion, Ledger, Gateway Adapter) running in isolated Kubernetes containers.
- PostgreSQL Read Replicas: Implemented CQRS to separate heavy read queries (dashboard analytics) from the critical transaction writes.
The Impact
The migration was completed in 8 months with zero downtime.
- The system easily handled the subsequent Black Friday with zero dropped transactions.
- Cloud hosting costs were reduced by 40% due to dynamic container auto-scaling.
- New payment gateways can now be integrated in weeks instead of months thanks to the decoupled adapter pattern.