Bazel Flag Cheat Sheet

Navigating Bazel’s extensive list of command line flags can be a challenge. This page focuses on the most crucial flags you’ll need to know.

Select the flag name in table to navigate to its entry in the command line reference.

Useful general options

The following flags are meant to be set explicitly on the command line.

—config

You can organize flags in a .bazelrc file into configurations, like ones for debugging or release builds. Additional configuration groups can be selected with --config=<group>.

See command line reference

—keep_going

Bazel should try as much as possible to continue with build and test execution. By default, Bazel fails eagerly.

See command line reference

—remote_download_outputs

When using remote execution or caching (both disk and remote), you can signal to Bazel that you want to download all (intermediate) build artifacts as follows:

--remote_download_outputs=all

By default, Bazel only downloads top-level artifacts, such as the final binary, and intermediate artifacts that are necessary for local actions.

See command line reference

—stamp

Adds build info (user, timestamp) to binaries.

Because this increases build time, it’s only intended for release builds.

See command line reference

Uncover Build & Test Issues

The following flags can help you better understand Bazel build or test errors.

—announce_rc

Shows which flags are implicitly set through user-defined, machine-defined, or project-defined .bazelrc files.

See command line reference

—auto_output_filter

By default, Bazel tries to prevent log spam and does only print compiler warnings and Starlark debug output for packages and subpackages requested on the command line. To disable all filtering, set --auto_output_filter=none.

See command line reference

—sandbox_debug

Lets you drill into sandboxing errors. For details on why Bazel sandboxes builds by default and what gets sandboxed, see our sandboxing documentation.

If you think the error might be caused by sandboxing, try turning sandboxing off temporarily.

To do this, add --spawn_strategy=local to your command.

See command line reference

—subcommands (-s)

Displays a comprehensive list of every command that Bazel runs during a build, regardless of whether it succeeds or fails.

See command line reference

Startup

Startup flags need to be passed before the command and cause a server restart. Toggle these flags with caution.

—bazelrc

You can specify default Bazel options in .bazelrc files. If multiple .bazelrc files exist, you can select which one to use with --bazelrc=/path/to/.bazelrc.

To ignore all .bazelrc files, use --bazelrc=/dev/null.

See command line reference

—output_base

Bazel stores all data at ~/.cache/bazel/_bazel_$USER by default. If this directory is on a network drive, you may want to relocate it to local storage using --output_base=/path/to/base.

See command line reference

Set Bazelrc files

You can control which .bazelrc files Bazel reads and in what order.

—bazelrc

Specifies the path to a .bazelrc file to use. Can be passed multiple times.

See command line reference

—nosystem_rc

Prevents reading system-wide .bazelrc files.

See command line reference

—noworkspace_rc

Prevents reading workspace .bazelrc files.

See command line reference

—nohome_rc

Prevents reading home directory .bazelrc files.

See command line reference

Building and Testing

Flags for optimizing your build and test workflows.

—jobs (-j)

Controls how many parallel jobs Bazel runs. The default is based on your host’s capacity. Setting it too high may cause thrashing, while setting it too low underutilizes resources.

bazel build --jobs=50 //my:target

See command line reference

—local_resources

Explicitly sets the amount of local resources (RAM, CPU) that Bazel can use. Useful when running builds on machines with limited resources.

--local_resources=12000,8,1.0

See command line reference

—test_output

Controls how test output is displayed:

• summary - shows only final summary (default)
• errors - shows output from failed tests
• all - shows all test output
• streamed - streams test output in real-time

bazel test --test_output=errors //my:test

See command line reference

—test_filter

Runs only tests whose names match the specified pattern. Useful for running a subset of tests.

bazel test --test_filter=MyTestCase.testMethod //my:test

See command line reference

—cache_test_results

Controls whether test results are cached. Set to no or false to force tests to re-run even if nothing has changed.

bazel test --cache_test_results=no //my:test

See command line reference

Remote Execution and Caching

Flags for configuring remote build execution and caching.

—remote_executor

Specifies the remote execution endpoint.

--remote_executor=grpc://remote.build.example.com:8080

See command line reference

—remote_cache

Specifies the remote cache endpoint.

--remote_cache=grpc://cache.build.example.com:8080

See command line reference

—remote_timeout

Sets the timeout for remote execution and cache operations.

--remote_timeout=60s

See command line reference

Debugging

Flags to help debug build issues.

—explain

Generates a detailed explanation of why each action was executed, writing it to the specified file.

bazel build --explain=explain.log //my:target

See command line reference

—verbose_explanations

Provides more detailed explanations when used with --explain.

See command line reference

—profile

Generates a JSON profile of the build, useful for performance analysis.

bazel build --profile=profile.json //my:target

You can analyze the profile with bazel analyze-profile profile.json.

See command line reference

Output Control

—output_filter

Filters build output to show only messages from targets matching the specified pattern.

--output_filter=^//my/package

See command line reference

—show_progress

Controls whether to show progress messages during build.

See command line reference

—show_progress_rate_limit

Sets the minimum time between progress updates (in seconds).

--show_progress_rate_limit=1.0

See command line reference

Sandboxing

—spawn_strategy

Controls the execution strategy for actions. Common values:

• sandboxed - run in sandbox (default on Linux/macOS)
• local - run without sandboxing
• worker - use persistent worker processes
• remote - execute remotely

--spawn_strategy=local

See command line reference

—sandbox_tmpfs_path

Mounts a temporary filesystem at the specified path within the sandbox. Can improve performance for heavy I/O operations.

--sandbox_tmpfs_path=/tmp

See command line reference

Configuration

—compilation_mode (-c)

Sets the compilation mode:

• fastbuild - fast compilation with minimal optimizations (default)
• opt - optimized build for release
• dbg - debug build with symbols

bazel build -c opt //my:target

See command line reference

—platforms

Specifies the target platform for the build.

--platforms=@platforms//os:linux

See command line reference

—cpu

Specifies the target CPU architecture. Being replaced by --platforms.

--cpu=k8

See command line reference