Test-Driven Development (TDD) focuses on writing tests before writing the actual code. This method helps developers build reliable and clean software from the start. TDD is often explained as a process where a test is written first, then code is added only to pass that test. The TDD approach ensures that every feature is tested and works as expected. To understand what is test driven development, it is a practice that follows a simple cycle: write a test, write code, and then improve the code. In TDD development, bugs are found early, which saves time and reduces rework. One of the main benefits of TDD is better code quality because the code is simpler and easier to maintain. Another key point among the advantages of test driven development is improved confidence during changes, as tests quickly show if something breaks. Conclusion: TDD helps create stable, well-tested software. By following test-first coding, teams achieve cleaner code, fewer bugs, and long-term project stability.