Migration

Translation boundary protecting a bounded context's model from upstream language corruption; structure (FACADE+ADAPTER); ACL vs Conformist vs Open-Host Service; migration use with Strangler Fig

Modularity drivers (availability, scalability, deployability, testability, maintainability); scalability vs elasticity; component-based vs tactical forking; six decomposition patterns; architecture stories

Migration for deeply embedded capabilities: 5 steps; feature toggles; verify variant with automatic fallback

Observing DB changes as event stream; log-based (Debezium, WAL/binlog/oplog), trigger-based, query-based mechanisms; CDC vs event sourcing; dual-write problem solved by outbox + CDC; data liberation patterns; strangler migration; schema coupling; log-compacted topics for bootstrap; backpressure on consumers

How far to decompose: modular monolith → service-based → microservices; five decision factors (domain understanding, team structure, DevOps maturity, transaction requirements, scalability); recommended migration path; granularity disintegrators vs integrators; Ferrari anti-pattern

Eight types of natural split points for monolith decomposition: business domain (primary), regulatory compliance, change cadence, team location, risk, performance, technology (sparingly), user personas; six forms of monolith; distributed monolith anti-pattern

Decision tree: where's the seam, is correctness the dominant risk, granularity, duration, parallel-run cost; pattern composition (service extraction, embedded capability extraction, database split, platform migration); database decomposition patterns; rollback as a feature

*Monolith to Microservices* — Sam Newman

Correctness verification: both implementations run per request; old result returned; GitHub Scientist; dark launching vs canary vs parallel run; progressive delivery

Incremental migration pattern: identify → implement → redirect via proxy; HTTP/FTP/message variants; UI composition (page, widget, micro frontends); deployment ≠ release; feature freeze