AspectExtension Language
Fill Bazel usability gaps with AXL and extend tasks anywhere.
Why AXL
Bazel is fast, scalable, and battle-tested in the enterprise.
But anyone who’s used it knows: some important workflows are… missing, awkward, or just not adapted to your organization.
These include:
Coverage
Formatting
Linting
Test reporting
Documentation
Release automation
That’s where AXL extensions come in.
They extend the build system with novel tasks that solve the real problems Bazel developers face every day.
About AXL
Aspect Extension Language (AXL) is a dialect of Starlark — the same language Bazel itself uses. That means extensions are:
Familiar
If you’ve ever read a Bazel BUILD file or rule, AXL will be readable.
Safe and deterministic
No hidden side effects, no unbounded execution — perfect for reproducible builds.
Composable
Tasks can interact with Bazel’s query and build APIs while staying lightweight and easy to share.
By using Starlark, AXL makes it possible to write high-level workflow automation that still feels native to Bazel.
