Monolith → Services Extraction

"Rewrite as services" never works. "Extract one service incrementally over 3-6 months" sometimes does. This skill walks the strangler fig pattern that keeps the monolith working while the new service grows.

The opinion

Use the strangler fig pattern. Do schema-level decoupling FIRST (separate tables / DB). Dark-launch the new service (production traffic, results discarded). Then dual-write (both systems write, old is source of truth). Then dual-read (both serve, compare). Finally, cut over. Keep the rollback path open until you've gone a full month without rolling back.

The whole point: at no time should production be broken. Every step is reversible until the very last cleanup.

The 7-stage strangler fig