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Cloud & DevOps E-commerce group 2024

A zero-downtime monolith to microservices migration

Strangler-fig migration of a decade-old monolith into 140+ services — with zero customer-facing downtime.

0
downtime minutes
140+
services shipped
deploy frequency

## The challenge
A monolith that everyone was afraid to touch. Releases were quarterly, risky and all-hands.

## What we did
- Applied the strangler-fig pattern, peeling off bounded contexts one at a time behind a service mesh.
- Codified infrastructure in Terraform and standardised delivery with ArgoCD GitOps.
- Added contract tests and progressive delivery so every cutover was reversible.

## Outcome
The team now ships multiple times a day instead of once a quarter — and the migration completed without a single minute of customer-facing downtime.

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