Test-driven development (TDD) is a practice of writing automated tests before writing the production code, and then refactoring the code to make it pass the tests. TDD helps ensure that the code is correct, maintainable, and meets the requirements. Pair programming is a practice of having two programmers work together on the same code, one as the driver who writes the code, and the other as the navigator who reviews the code and provides feedback. Pair programming helps improve the quality of the code, share knowledge, and reduce defects. Continuous Integration (CI) is a practice of integrating and testing the code frequently, usually several times a day, using automated tools. CI helps detect and fix errors early, improve collaboration, and deliver faster. References: What Is Extreme Programming (XP)? - Values, Principles, And Practices, What is Extreme Programming (XP)? | Agile Alliance, What are 3 practices of Extreme Programming? – ProfoundQa, What are three practices of Extreme Programming (XP)? (Choos - Madanswer