Why Strangler fig pattern in Microservices? - Purpose & Use Cases

The Big Idea

What if you could upgrade your whole system without breaking it or stopping users?

The Scenario

Imagine you have a big old software system that everyone depends on. You want to add new features or fix problems, but changing the old system is risky and slow. Every change might break something else, and the whole team waits for long testing cycles.

The Problem

Trying to rewrite or fix the entire system at once is like rebuilding a house while living inside it. It takes too long, causes many errors, and users get frustrated with downtime or bugs. The team feels stuck, unable to move fast or improve smoothly.

The Solution

The Strangler fig pattern helps by letting you replace parts of the old system little by little. You build new features outside the old system and slowly redirect users to the new parts. Over time, the old system 'dies off' naturally, without big risks or downtime.

Before vs After

✗ Before

Rewrite entire system in one go
// Big risky deployment
// Long downtime

✓ After

Build new service
Redirect some requests
Gradually replace old parts

What It Enables

This pattern enables smooth, safe upgrades and faster innovation without stopping the whole system.

Real Life Example

A company moves from a monolithic app to microservices by slowly replacing user login, then payments, then profiles, each as separate services, without shutting down the app.

Key Takeaways

Big rewrites are risky and slow.

Strangler fig pattern replaces parts gradually.

It allows safe, continuous improvement.