Modernising a Legacy Banking Portal on AWS
Zero-downtime migration of a major banking portal from monolithic IBM WebSphere to serverless AWS.
Overview
A major bank's customer portal was trapped in a rigid legacy infrastructure. Feature releases were painfully slow, scaling was constrained, and operational risk was climbing.
I architected and executed a zero-downtime cloud migration to safely decouple the user interface from the legacy backend. Using a highly phased routing strategy, we transitioned traffic incrementally. The programme transformed a fragile monolith into an elastic, secure cloud platform without interrupting a single authenticated customer session in production.
Outcomes
| Metric | Result |
|---|---|
| Customer Downtime | Zero disruption to live production traffic |
| Traffic Handled | Successfully absorbed 40,000+ peak concurrent sessions |
| Compute Cost Reduction | Slashed baseline infrastructure spend by roughly 30% |
| Deployment Velocity | Shifted from sluggish quarterly releases to on-demand |
Stack
AWS Route 53 · CloudFront · AWS WAFv2 · Application Load Balancer · Amazon ECS Fargate · Amazon ElastiCache Redis · Terraform · GitHub Actions