IntermediateSITUATIONAL
Given a monolithic Node.js app experiencing slow page loads and frequent deploy conflicts, outline a practical migration and execution plan to move to a componentized full‑stack architecture while minimizing user impact.
Full Stack Developer
General

Sample Answer

At my last role we had a Node.js monolith serving ~250k monthly users, page loads averaging 2.8s and weekly deploy conflicts blocking releases 30% of the time. I proposed a phased componentization: first, set clear module boundaries and extract a single low-risk feature (user settings) into a lightweight service with its own CI/CD and contract tests. We ran it behind the existing monolith via a BFF proxy and feature flag, measuring latency and error rates in real time. Over six sprints we extracted three more components, reduced full-stack deploys from daily to per-component (cutting merge conflicts by 80%), and improved median page load to 1.2s. Key practices were automated contract tests, Canary releases, team-owned services, and rollbackable feature flags to keep user impact near zero.

Keywords

Phased extraction with BFF/proxy and feature flagsAutomated contract tests and per-component CI/CDCanary deployments and rollback strategy to minimize user impact