API Platform Modernization

The Challenge

The client operated a growing SaaS platform with a monolithic REST API that had become increasingly difficult to maintain. Response times were averaging 800ms, and the tightly coupled architecture made it challenging to add new features without risking regressions. Their mobile and web clients were making excessive API calls to fetch related data, leading to poor user experience and high server costs.

Our Approach

We conducted a thorough analysis of their existing API usage patterns and identified the most frequently accessed data relationships. Rather than a risky big-bang rewrite, we implemented a strangler fig pattern, gradually migrating endpoints to a new GraphQL layer while maintaining backward compatibility. We established a comprehensive test suite and set up feature flags to safely roll out changes.

The Solution

The new GraphQL API was built with Node.js and Apollo Server, backed by PostgreSQL with optimized query patterns. We implemented DataLoader for efficient batching and caching, reducing N+1 query problems. The architecture included a Redis caching layer for frequently accessed data. Comprehensive monitoring with custom metrics provided visibility into API performance.

Results & Impact

Client Testimonial