Definition
A migration strategy where a new system is built around the edges of an old system, gradually intercepting and replacing functionality until the old system can be decommissioned.
Why It Matters
Rewriting a legacy system from scratch ('The Big Bang') fails 90% of the time. This pattern allows you to migrate risk-free while keeping the business running.
How It Works
- 1
Put a proxy (API Gateway) in front of the legacy system.
- 2
Build a new microservice for ONE specific feature (e.g., 'User Login').
- 3
Route traffic for that feature to the new service.
- 4
Repeat until the legacy system receives no traffic.
The NetForce Take
This is how we migrate 10-year-old PHP monoliths without downtime. It's the only safe way to modernize enterprise software.