---
title: "Strangler Fig Migration Pattern — Definition & Engineering Context"
description: "The Strangler Fig Pattern is a software migration strategy that incrementally replaces a legacy monolithic system by gradually routing specific business functions to a new modern service, allowing a zero-downtime transition without a risky big-bang rewrite."
canonical: https://erpstack.io/glossary/strangler-fig
markdown_url: https://erpstack.io/glossary/strangler-fig.md
publisher: ERPStack
---

# Strangler Fig Migration Pattern

> **Definition:** The Strangler Fig Pattern is a software migration strategy that incrementally replaces a legacy monolithic system by gradually routing specific business functions to a new modern service, allowing a zero-downtime transition without a risky big-bang rewrite.

## In depth

Named after the strangler fig tree that grows around a host tree until the host is no longer needed, this pattern involves placing an API gateway in front of the legacy system. New features are built in the modern stack and routed through the gateway. Existing functionality is moved piece by piece — inventory first, then billing, then HR — until the legacy system handles zero traffic and can be decommissioned. This is the industry-standard approach for migrating from SAP R/3, Oracle EBS, and .NET monoliths without operational downtime.

## How ERPStack applies this

We execute Strangler Fig migrations using Next.js API routes as the façade gateway. We use Debezium CDC (Change Data Capture) for continuous data replication from the legacy database to PostgreSQL, ensuring zero data loss during the transition window.

## Related reading

- [Cloud Migration](https://erpstack.io/glossary/cloud-migration)
- [Monolithic Architecture](https://erpstack.io/glossary/monolith)
- [ERPStack vs SAP](https://erpstack.io/alternatives/sap)