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FinTech

How We Scaled a FinTech Platform to Handle 10M+ Daily Transactions

Scaling a FinTech Platform to Handle 10M+ Daily Transactions

The Challenge

A leading regional FinTech provider approached Speion with a critical bottleneck. Their monolithic application, built on a legacy LAMP stack, was struggling under the weight of exponential user growth. During peak trading hours, database locks and inefficient query structures caused API latencies to spike over 4 seconds, resulting in dropped transactions and severe customer dissatisfaction.

The requirements were strict:

  1. Handle 10,000 requests per second (RPS) at peak.
  2. Reduce P99 API latency to under 200ms.
  3. Zero downtime during the migration.

The Architecture Solution

1. Event-Driven Microservices

We dismantled the monolith into domain-specific microservices (Authentication, Ledger, Payment Gateway, Notifications) written in Node.js and Go. To handle cross-service communication without tight coupling, we introduced an Event-Driven Architecture using Apache Kafka.

2. CQRS and Read Replicas

To solve the database locking issues, we implemented the Command Query Responsibility Segregation (CQRS) pattern.

  • Writes (Commands): Directed to a highly optimized primary PostgreSQL cluster.
  • Reads (Queries): Directed to heavily cached Redis layers and read replicas, ensuring that heavy analytical queries didn't block live transactions.

3. Kubernetes Orchestration

The entire infrastructure was containerized and deployed to a Kubernetes cluster. We configured Horizontal Pod Autoscaling (HPA) to automatically spin up new instances of the Payment Gateway service during market open, and scale down during off-hours to optimize cloud spend.

The Results

Within 4 months, the migration was completed seamlessly using the Strangler Fig pattern.

  • Throughput: Successfully processed 12.4 million transactions on the first peak day without a single dropped request.
  • Latency: P99 API latency dropped from 4,200ms to 115ms.
  • Infrastructure Costs: Reduced monthly cloud spend by 35% through efficient auto-scaling and resource allocation.

Does your application need to scale? Speion specializes in high-throughput enterprise architectures. Contact us today.