TL;DR — Monolith to Microservices Migration

You maintain a 500K LOC Ruby on Rails monolith for an online marketplace. 30 developers across 5 teams commit to the same repo. The application handles user management, product listings, search, orders, payments, reviews, and notifications — all in one deployment. The PostgreSQL database has 200+ tables with extensive foreign key relationships. CI takes 45 minutes, deploys take 2 hours with a 15% rollback rate. Key features: Marketplace must remain fully operational during migration. Each team can deploy their service independently.