The Desi Architect
Notes / Design Interview Problems / Decompose a Monolith into Microservices (The Production Migration Blueprint)
Track 5 · Design Interview Problems

Decompose a Monolith into Microservices (The Production Migration Blueprint)

How a high-scale Indian platform migrates from a single shared database to independent domain services with continuous uptime, reliable sagas, and no distributed monolith trap.

An architectural blueprint for breaking down a monolithic codebase into microservices using the Strangler Fig pattern, database-per-service isolation, Transactional Outbox with Debezium Change Data Capture (CDC), orchestrated Sagas, and a 4-tier resilience chain.

Interview problem45 min read
On this page
  1. Why this problem is hard
  2. What are we building?
  3. Entities, API and numbers
  4. Building it up, one step at a time
  5. Where it gets hard
  6. Failure modes at a glance
  7. The whole picture
  8. How interviewers judge this
  9. Questions that come next
  10. Saying it out loud in 45 minutes
  11. Sources and assumptions