Bazel
Bazel is a free, open-source tool for automating software builds and tests across languages and platforms. Projects declare build targets in BUILD files using Starlark, which can also be used to create custom rules and macros. Bazel caches completed work, rebuilds what has changed and supports parallel execution. It handles languages including C++, Java, Kotlin, Python, Go and Rust, and can produce outputs for desktop, server, Android and iOS. It runs on Linux, macOS and Windows. Sandboxing can make builds and tests more hermetic, while non-zero exit codes on failed invocations support basic CI integration. Teams can share outputs through a remote cache, but need to select and maintain a backend server and secure access because the cache may hold binaries. The documentation says Bazel can manage builds involving 100,000 or more source files and multiple repositories. It is particularly suited to large codebases, multiple compiled languages, multi-platform deployments and extensive test suites.
Who it is for
Bazel suits software teams working with large codebases, multiple compiled languages, multi-platform targets or extensive tests. It is also relevant where teams want incremental builds and can manage a remote cache backend if needed.
What is good
- Caches prior work and rebuilds changed parts.
- Supports parallel builds across several languages.
- Builds outputs for desktop, server, Android and iOS.
- Sandboxing can improve build reproducibility.
- Runs on Linux, macOS and Windows.
What to know first
- Remote cache requires a separately managed backend.
- Remote cache access needs security controls.
- Not well suited to uncached deployment operations.
- Some distribution packages are community-supported, not official.
Verdict
Bazel offers a free build-and-test system with incremental execution, broad language support and multi-platform outputs. Its remote cache and deployment limitations matter for teams deciding how to fit it into their workflows.
Bazel plans and pricing
All plansCompared on build automation software
- Free plan
- Yes
- Build as code
- Yes
- Dependency locking
- Yes
- Build caching
- Yes
- Remote execution
- Yes
- Artifact packaging
- Yes
- Supported operating systems
- multi-platform
