Legacy Modernisation: The 'Strangler' Pattern
The most terrifying phrase in software development is "The Big Rewrite." It promises a fresh start, but usually delivers years of delays and a product that does less than the old one.
There is a better way. And it's named after a tree.
The Strangler Fig Application
Named after the fig trees that grow around a host tree and eventually replace it, this architectural pattern is our preferred method for modernisation. The key insight:
We don't shut down the old system. We build the new system around it. Piece by piece, function by function, until the old system quietly fades away.
The Process
Identify the edges
Find a discrete piece of functionality—like user authentication or reporting—that can be extracted cleanly.
Build the new service
Create it using modern technology. Next.js, Supabase, serverless functions—whatever fits.
Reroute traffic
Use a load balancer or reverse proxy to send requests to the new service, while keeping the old system running for everything else.
Repeat
Piece by piece, the old system is strangled until nothing remains but the new.
This approach lets us deliver value in weeks, not years. Every step is a working product. Every migration is reversible. Risk is managed at every stage.