Faker is a popular open-source test data generation library available for multiple programming languages, including Python, Ruby, and JavaScript. It provides a wide range of data generation features, allowing users to create realistic test data based on custom data models. Faker supports various data types, including names, addresses, and dates, and offers an extensive list of data generation functions. With its easy-to-use API, Faker is an ideal solution for developers looking to generate test data programmatically.