What problem were we solving?
The legacy system could not scale to meet growing transaction volumes, and the tightly coupled architecture made even minor changes risky and slow.
Key Constraints
Zero-downtime migration required — cannot interrupt live payment processing
Regulatory compliance (PCI DSS) must be maintained throughout
Existing team of 12 engineers needed to operate the new system
Migration had to complete within 6 months
What paths were on the table?
Full rewrite from scratch
Strangler fig pattern with incremental migration
Buy an off-the-shelf payment platform
Refactor the monolith in place
The Decision
Chose the strangler fig pattern — incrementally extract services from the monolith while keeping the system running. This minimized risk while delivering value at each stage.
Measurable business outcomes
Transaction processing time dropped from 800ms to 320ms. Fraud detection became real-time, catching 40% more fraudulent transactions. Feature deployment frequency went from monthly to daily releases.
Have a similar challenge?
Tell us about your situation. We can share what worked and what did not from this project.
