Software Engineer (Backend) at Flink Commerce • Paul Babatuyi

Role Overview

Backend Software Engineer at Flink Commerce, a German e-commerce platform, working on domain-driven microservices with both REST and gRPC services.

Key Responsibilities & Achievements

Microservices Architecture

Worked on domain-driven microservices in Golang for a German e-commerce platform using clean layered architecture
Built REST API endpoints for client-facing features and gRPC services for internal service-to-service communication
Covered product catalogue, order management, cart, and inventory domains

Database Design & Optimization

Used MongoDB as the primary datastore for product catalogue, order, and inventory data
Designed collections and indexes to support efficient filtering, pagination, and aggregation across variable product schemas
Query tuning and index additions reduced p99 read latency by around 40% on high-traffic listing endpoints

Caching & Performance

Added Redis caching on product listing and search endpoints to reduce repeated MongoDB reads
Tuned TTL-based invalidation to balance freshness and performance
Cut average API response time on catalogue endpoints from ~300ms to ~80ms under normal load

Security & Testing

Implemented JWT-based stateless authentication and RBAC middleware across REST and gRPC routes
Added rate limiting and input validation
Wrote unit and integration tests across service boundaries following TDD
Maintained around 65% coverage on core business logic

DevOps & Monitoring

Packaged services with Docker and contributed to GitHub Actions CI/CD pipelines for automated test and deployment runs
Used Prometheus metrics and Grafana dashboards to monitor service health and track error rates
Cut average time to detect and diagnose production issues by around 35%

Languages: Golang
APIs: REST, gRPC
Databases: MongoDB, Redis
Security: JWT, RBAC
DevOps: Docker, GitHub Actions
Observability: Prometheus, Grafana
Testing: TDD, Unit & Integration Testing