The concept of “Shift Left” has long guided developers to address issues early in the software development lifecycle (SDLC), catching bugs before they reach production. But as modern software ecosystems become more complex—with microservices, serverless architectures, and global deployments—testing alone no longer suffices. It’s time to rethink Shift Left as more than just pre-release testing—it must evolve. Traditional testing strategies like Test-Driven Development (TDD) and Behavior-Driven Development (BDD) have been invaluable, ensuring code correctness and expected behavior. However, they miss critical aspects of real-world performance, scalability, and user experience. A passing test suite can’t guarantee an application won’t crash under peak loads or degrade due to subtle performance bottlenecks. Enter observability: the missing piece in the Shift Left equation. By integrating observability practices early in the SDLC, teams gain deep, actionable insights into how applications behave in production-like environments. Metrics, traces, and logs reveal performance slowdowns, scalability constraints, and user experience hiccups long before end users are affected.
Martin McLarnon is an engineer with almost 30 years experience working in many different roles within IT. He has worked as a Network Manager, Software engineer, Cloud Architect, Engineering lead and worked as an engineering consultant before joining Coralogix.