Strangler Fig Pattern — Migrating from a Monolith

Architecture Intermediate

Strangler Fig Pattern — Migrating from a Monolith¶

Strangler FigMigrationMonolith 3 min read

Gradual migration from monolith to microservices. A safe, incremental approach.

Principle¶

Named after the strangler fig tree that grows around its host. You gradually replace parts of the monolith with new services.

Steps¶

• Build a proxy/facade in front of the monolith
• Select a feature to extract (start with a simple one)
• Implement the new service
• Redirect traffic
• Remove the old code

server {
    listen 80;
    # Migrated
    location /api/orders { proxy_pass http://new-order-service:8080; }
    # Legacy
    location / { proxy_pass http://legacy-monolith:3000; }
}

Tips¶

• Start at the edges — features with the fewest dependencies
• Anti-Corruption Layer between old and new
• Feature flags for traffic switching
• Migration takes months to years — don’t rush

Summary¶

Strangler Fig is the safest path out of a monolith. No big bang, just gradual displacement of old code.

Need Help with Implementation?¶

Our team has experience designing and implementing modern architectures. We’re happy to help.

Free Consultation