Abstract
Organizations are challenged with integrating legacy systems and modern applications in a way that ensures operational harmony and business continuity. This article explores the concept of system coexistence, the ability of diverse software systems built across different eras and architectures to function together within shared environments. It delves into practical strategies for achieving coexistence, such as the Strangler Fig Pattern, adapter-based decoupling, and event-driven communication models. The article also addresses critical supporting aspects like data coexistence, observability, and performance monitoring, emphasizing that coexistence is not merely a transitional phase but a strategic imperative for sustainable growth and innovation. Drawing on real-world examples, such as Netflix’s cloud migration and the HealthCare.gov launch failure, this piece provides a roadmap for organizations to navigate coexistence successfully while preparing for scalable, future-ready systems.
Introduction
We live in a world where it’s easy to assume that all our applications built at different times, using the „best“ technologies of their era will seamlessly integrate and continue to function in harmony. Yet, time and again, we’re proven wrong.