Decoupling Monoliths: A Strategic Playbook

Most monolith-to-microservices migrations fail not because the target architecture is wrong, but because the migration itself is treated as a single, high-risk cutover instead of a sequence of small, reversible steps.

Start with the seams that already exist

Every monolith has natural seams — modules that already talk to the rest of the codebase through a narrow interface. Those are the cheapest first extractions, not the modules that "obviously" should be a service.

Strangle, don't rewrite

Route traffic for one seam at a time through a thin proxy layer, and move that seam's logic behind it incrementally. The rest of the system doesn't need to know anything changed.

Measure before you extract

If you can't answer "what does this module cost us today, in latency or on-call load," you don't yet have a strong enough case to extract it. Pull the data first.