Bazel is an open-source build and test tool that is designed to handle projects of any size, from small codebases to extensive, complex systems. It supports a variety of programming languages and platforms, allowing for fast and reliable builds. Bazel focuses on correctness and speed, using advanced dependency analysis to ensure that only necessary parts of the code are rebuilt, thus optimizing the development process. It is particularly popular for automating tasks in continuous integration pipelines and is used by major tech companies to manage code builds efficiently.