Legacy code—whether defined as code without tests, code written with outdated practices, or simply code you didn't write—presents unique challenges for development teams. These inherited codebases often contain critical business logic while suffering from technical debt, poor documentation, and outdated dependencies. Successfully working with legacy systems requires specialized skills and strategies beyond greenfield development. Our legacy code articles provide practical guidance for the reality of working with existing codebases. Learn approaches to safely understanding unfamiliar code, adding test coverage to untested systems, and making incremental improvements without breaking existing functionality.

Discover refactoring techniques that reduce complexity, strategies for modernizing outdated dependencies and frameworks, and approaches to documenting tribal knowledge. Explore how to balance new feature development with technical debt reduction, communicate the business case for modernization efforts, and decide between refactoring and rewriting. Whether you've inherited a legacy system, need to extend aging applications, or are planning a modernization initiative, these resources help you navigate the challenges of legacy code with confidence and practical strategies.