Full-Stack Development

Migrating a Legacy Monolith to a Typed Node.js/TypeScript Microservice Architecture

A fintech client needed to scale and stabilize their core application. We executed a full migration from a brittle PHP monolith to a resilient, fully-typed Node.js/TypeScript microservices architecture with full CI/CD. This resulted in a 99.99% uptime guarantee and increased engineering velocity by 3x due to the confidence provided by extensive E2E testing.

The Challenge: Instability Hindering Growth

Our fintech partner had reached a critical stage where their legacy application was preventing them from attracting enterprise clients. The monolithic structure made adding features risky, deployments were slow and often caused downtime, and the lack of strong typing led to frequent, difficult-to-trace bugs. The architecture was not ready for modern, rapid iteration.

DevoxLabs' Full-Stack Development Solution

We initiated a phased migration to a modern, reliable full-stack system:

Microservices Decoupling: Architected the application into distinct, self-contained microservices (e.g., User Auth, Payment Gateway, Reporting).

Typed Core: Built all new services using Node.js and TypeScript to enforce strict type-checking, catching the majority of common errors at compile time rather than in production.

CI/CD Pipeline with E2E Testing: Implemented GitHub Actions for Continuous Integration and Continuous Deployment, backed by a comprehensive E2E test suite that runs on every commit.

Reliability Assurance: Configured robust error monitoring and performance tracing with Prometheus and Grafana.

Measurable Outcomes

Reliability and delivery improvements after the migration.

MetricBefore DevoxLabsAfter DevoxLabsImprovement
Uptime Guarantee~99.5% (unstable)99.99%Near-Perfect Reliability
Time to Deploy (TTD)2 hours (with manual checks)15 minutes (automated)87.5% Faster Deployment
Engineering Velocity (Features/Sprint)Low and inconsistent3x IncreaseAccelerated Roadmap
Production Bug Count (Critical)8-10 per month0-1 per month90%+ Reduction
Code Maintainability IndexLow (Legacy)High (Typed)Improved Long-Term Cost