Monolith to Microservices
A staged decomposition of a legacy monolith into fault-isolated services, orchestrated across AWS with a zero-downtime cutover.
Project Overview
The legacy monolith had grown into a single deploy unit no one dared touch. We mapped its transaction boundaries, extracted the hottest paths into independent Docker services, and fronted them with an API gateway. CI/CD pipelines now ship each service on its own cadence, cutting deploy risk to near zero.
System Features
Service boundaries: Domain-driven splits carved along transaction seams to isolate failure.
Gateway routing: A single API gateway fronts the mesh, handling auth and rate limits.
Blue-green deploys: Automated pipelines shift traffic between fleets with instant rollback.
SYS_SPECS
- Platform:
- AWS ECS
- Containers:
- Docker
- Pipeline:
- GitHub Actions
- Runtime:
- Node.js
ARC_MAP
Challenges & Solutions
# Threat: Distributed State
Splitting a shared database across services risked inconsistent reads and orphaned writes during the migration window.
# Remedy: Event Sourcing
An append-only event log became the source of truth; services rebuild local views asynchronously, tolerating partial outages.