TDD (Test-Driven Development) and BDD (Behavior-Driven Development) are both popular approaches in modern software testing, but they focus on different aspects of quality and development. Understanding the differences can help teams choose the right methodology for their workflow.

Test-Driven Development (TDD) is a coding practice where developers write tests before implementing the actual functionality. The process follows a simple cycle: write a failing test, implement the minimum code to pass the test, and then refactor. TDD emphasizes correctness at the code level and helps ensure that each unit of functionality behaves as intended. It improves test coverage, reduces defects early, and encourages cleaner, modular code. However, TDD tests are often technical and may not directly reflect user behavior.

Behavior-Driven Development (BDD), on the other hand, focuses on the expected behavior of the system from a user or stakeholder perspective. BDD uses natural language constructs and scenarios, often in “Given-When-Then” format, to define requirements and tests. This makes tests easier to understand for non-technical stakeholders and ensures that development aligns closely with business expectations. BDD encourages collaboration between developers, testers, and business analysts, promoting shared understanding of system behavior.

While TDD targets technical correctness and code quality, BDD emphasizes communication, collaboration, and user-focused outcomes. Many teams combine the two: using**tdd vs bdd** for high-level acceptance tests. Together, they provide a comprehensive approach that improves both code reliability and alignment with user expectations.