Not every system needs microservices. Start with clear bounded contexts and measurable pain: deploy coupling, scaling asymmetry, or team ownership friction that a modular monolith cannot solve.
Strangler patterns, API gateways, and shared observability reduce risk during decomposition. Extract edges first—reporting, notifications, or read-heavy paths—before cutting into the transactional core.
Data ownership is the hard part. Avoid distributed transactions until you have clear consistency models; prefer eventual consistency with well-defined compensation where business rules allow.
Invest early in contract testing, schema evolution, and platform tooling—otherwise distributed systems amplify operational load faster than they unlock velocity.
Team topology should lead architecture. Services without clear owners become orphaned liabilities. Align service boundaries with team cognitive load.
Platform capabilities—identity, logging, messaging, CI/CD, and golden paths—must mature alongside decomposition. Without them, every new service reinvents plumbing.
Measure success by lead time, change failure rate, and recovery—not by service count. Modernization is a product journey, not a rewrite event.