Bazel Blog

Bazel Q1 2026 Community Update

Wed, 08 Apr 2026 00:00:00 +0000

Announcements

Mark Your Calendars: BazelCon 2026 is Heading to Amsterdam!

Get ready to build at scale in the heart of Europe. We are thrilled to announce that BazelCon 2026 will be taking place in the vibrant city of Amsterdam from October 13th–15th.

Whether you’re a seasoned build engineer or just starting your journey with monorepos and hermeticity, this is the place to be. Expect three days of deep-dive technical sessions, hands-on workshops, and the chance to connect with the global community of maintainers and power users.

The Details at a Glance:

What: BazelCon 2026
Where: Postillion Hotel & Convention Centre Amsterdam, Netherlands
When: October 13–15, 2026
- October 13th - Training Day
- October 14th & 15th - 2 Conference days filled with technical sessions, Birds of a Feather and networking with the best in the field.

Registration opens April 22nd - register via the BazelCon website!

For the most up to date BazelCon news and updates, follow the Bazel X account and the #bazelcon Bazel Slack channel.

Call for Proposals

Do you have a Bazel story to tell? We want to hear how you're using Bazel to solve complex problems, whether you’re optimizing massive monorepos or building custom rules for your team. Sharing your real-world wins and lessons learned helps the entire community grow, so don't hesitate to submit a proposal regardless of your experience level.

CFP Opens: April 22
CFP Closes: June 21
Review Period: June 22 – July 8
Speaker Notifications: July 20
Schedule Announcement: July 22

The CfP submission form will be available via the BazelCon website.

Want to become a Sponsor of BazelCon 2026?

Hosted by the Bazel Community in partnership with The Linux Foundation, BazelCon is the premier annual event for build enthusiasts, maintainers, and contributors to connect in an inclusive environment.

Sponsoring BazelCon 2026 puts your company right in front of the best build and platform engineers in the business. It is a great way to show your support for the community, meet key decision-makers, and find top talent to join your team. By becoming a partner, you help make the event possible while making sure the smartest people in tech know exactly who you are.

Download the 2026 Sponsorship Prospectus Here.

Email us at bazelcon-planning@bazel.build to reserve your sponsorship, ask questions, or talk about different options.

Product Updates

Upcoming Bazel releases

Bazel 9.1.0 is expected to release on on 2026-04-16. Please send cherry-pick PRs against the release-9.1.0 branch before the RC1 cutoff on 2026-04-09.

Bazel 8.7.0 is expected to release on 2026-05-04. Please send cherry-pick PRs against the release-8.7.0 branch before the RC1 cutoff on 2026-04-27.

Q4 & Q1 releases

9.0.0 has been released in January ‘26, followed by patch 9.0.1.
8.6.0 has been released in February ‘26.
8.5.0 has been released in December ‘25, followed by patch 8.5.1.
7.7.0 has been released in October ‘25, followed by patch 7.7.1.
6.6.0 has been released in January ‘26. This release has also marked the end of support for Bazel 6.

Community Corner

Bazel for CLion plugin updates

A few updates from the JetBrains* team:

Plugin supports Bazel 9 and comes now with Starlark REPL.
C++ code insight under transitions is being rolled out. CLion Classic lets the user select resolve configuration for such files if more than one configuration is available, CLion Nova support for configuration switching is on the way.
GoogleTest TEST_P macro is supported for individual test runs.
Code insight takes into account conlyopts and cxxopts attributes.
New PTY capable view is enabled by default for all outputs.

BUILD Foundation

Announced at BazelCon 2025, the BUILD Foundation has been established as a Linux Foundation Directed Fund to accelerate the community roadmap for Bazel and related build technologies. While Google maintains governance of the core Bazel "kernel," the new fiscal entity provides a formal structure to fund improved documentation, rulesets, and open-source infrastructure.

The BUILD Foundation is now enrolling founding members.

Read the Prospectus and Membership Entitlements to learn more about the values of becoming a member.

Web Updates: Previews for the BCR and Bazel.build

A New Look for the BCR: The community is working together on a more modern way to explore the Registry. Head over to bcr.stack.build to see the new UI in action and see how the ecosystem is evolving.

Evolving Bazel.build: Thanks to a collaborative effort, the next version of our homepage is taking shape. Visit preview.bazel.build to see how we’re making documentation and resources easier for everyone to navigate.

Upcoming Meetup.build events

Build Meetup Munich - May 11, 2026

Community created content

Articles

Goodbye Dockerfile, Hello Bazel: Doubling Our CI Speed - by Nikita Chepanov and Oleg Dashevskii at Plaid

Build less, merge faster: avoiding diamond merges with a merge queue - by Nikita Chepanov and Oleg Dashevskii at Plaid

Bazel 9 Migration: How to Get Faster Builds Before the Bzlmod Refactor - by Pratik Mahalle

Bazel for SONiC: What We've Learned and Contributed - by Şahin Yort

Managing Bazel Flags in Monorepos with Flagsets (PROJECT.scl) - by Adin Ćebić

Composing Bazel rules with subrules - by Adin Ćebić

Lightning-fast BUILD file generation with Gazelle lazy indexing - by Jay Conrod @EngFlow

Bazel rule extensions - by Keith Smiley

Build Snippets #1 - Affected Target Analysis with Bazel - by Chris McDonald

Migrating to Bazel symbolic macros - by Alexey Tereshenkov @Tweag

Videos

Bazel 9 is here! - by Aspect Build

Tutorial: Set up Gazelle to automatically create your Bazel BUILD files - & other beginner friendly videos by Jon Block here.

Bazel and Rust at OpenAI with David Zbarsky - by Aspect Build

Zero-sysroot hermetic LLVM cross-compilation using Bazel - FOSDEM talk by David Zbarsky and Corentin Kerisit

Resources

GitHub repository: https://github.com/bazelbuild/bazel
Releases: https://github.com/bazelbuild/bazel/releases
Slack chat: https://slack.bazel.build
Google group: bazel-discuss@googlegroups.com
Special Interest Groups (SIG):

Reach out the email(s) listed below if you’d like to be added to the SIG calendar invites.

SIG	Meeting frequency	Point of contact
Rules authors	Every two weeks	bazel-contrib@googlegroups.com
Android app development	Monthly	ahumesky@google.com
Bazel plugin for IntelliJ	Monthly	en@jetbrains.com
Remote execution API working group	Monthly	chiwang@google.com
Supply chain security / SBOM	Weekly	fwe@google.com

Interested in learning about SIGs or starting a new one? Find more information on our website.

Want to get your SIG listed? Please add it to the Community repository.

Ideas, feedback, and submissions are welcome!

Thank you for reading this edition! Let us know if you’d like to see any new information or changes in future community updates by reaching out to product@bazel.build. We look forward to hearing from you.

Thanks,

Google Bazel team

Dependabot Now Supports Bazel Version Updates

Fri, 20 Feb 2026 00:00:00 +0000

We're thrilled to announce Bazel support in Dependabot Version Updates! 🎉 Through a collaboration between the Bazel and Dependabot teams, along with feedback from both communities, Dependabot now handles both Bzlmod and WORKSPACE dependencies with proper lockfile generation.

The Journey to Bazel Support

Since 2019, the community has been asking for Bazel support in Dependabot (issue #2196). When the Dependabot team began building this, they reached out to the Bazel community in discussion #27142 to understand what mattered most. The feedback was clear: proper lockfile generation is critical, *.MODULE.bazel support is needed, and many teams are still on WORKSPACE. Even though WORKSPACE is approaching end-of-life, supporting it was the right call because that's where many users still are today.

Why Bazel Support Is Challenging

Bazel presents unique challenges that make dependency management more complex than other ecosystems:

Two Dependency Systems: Bazel has both the modern Bzlmod system (using MODULE.bazel files) and the legacy WORKSPACE system. Each works differently, and teams are at various stages of migration between them. Even though WORKSPACE is being phased out, community feedback showed many teams still rely on it. Support for both systems was essential.

Non-Trivial Lockfile Generation: Bazel's MODULE.bazel.lock files capture complex transitive dependency graphs including module extensions and repository rules, which goes beyond typical package manager lockfiles. Getting lockfile generation wrong breaks reproducible builds, so Dependabot worked closely with the Bazel community to ensure we got this right.

Community Migration in Progress: While Bzlmod is the future (enabled by default in Bazel 8), a significant number of users still rely on WORKSPACE. Supporting both ensures users are met where they are.

Built in Partnership with Bazel

This feature came together through close collaboration between the Dependabot and Bazel teams and community:

Lockfile semantics: Fabian Meumertzheim worked closely with the Dependabot team to ensure their lockfile generation matches Bazel's behavior exactly
Registry integration: Understanding how to properly query and use the Bazel Central Registry
Migration patterns: The Bazel team shared insights into how real teams are moving from WORKSPACE to Bzlmod
Testing and validation: Yun Peng provided invaluable support and data to validate Dependabot's implementation
File naming conventions: Alex Eagle helped clarify the *.MODULE.bazel pattern and other edge cases

A big thank you to everyone in both communities who tested this and provided feedback. This wasn't just us building a feature; it was a true partnership from start to finish.

How It Works

Dependency Detection: Dependabot scans your MODULE.bazel and *.MODULE.bazel files (or WORKSPACE) for dependencies and checks the Bazel Central Registry for updates.

Lock File Management: When updating dependencies, Dependabot properly regenerates lock files to maintain reproducible builds, the most critical piece to get right.

Pull Requests: Dependabot opens PRs with updated dependency declarations, regenerated lock files, release notes, and compatibility information.

Getting Started

To enable Dependabot for your Bazel project, you'll need:

Bazel Version: Your project must be using Bazel 7, 8, or 9, as these are the supported versions.

Project Configuration: A MODULE.bazel or WORKSPACE file is required at the root of your repository.

Dependabot Integration: Add the Dependabot configuration by creating a .github/dependabot.yml file and including the necessary YAML configuration.

updates:
  - package-ecosystem: "bazel"
    directory: "/"
    schedule:
      interval: "weekly"

Customization (Optional): All standard Dependabot configuration options are available, including custom schedules, grouped updates, and dependency ignores. See the Dependabot options reference for details.

Once configured, Dependabot will start watching your Bazel dependencies and opening PRs when updates are available.

Try It Out

Bazel support is now generally available to all Dependabot and Bazel users. Check out the changelog on Github and Dependabot's documentation for getting started.

We're excited to see how this helps the Bazel community keep their dependencies secure and up-to-date. Open source is a team sport, and this feature is proof of what's possible when teams work together across projects.

Bazel 9 LTS

Tue, 20 Jan 2026 00:00:00 +0000

We're pleased to announce the release of Bazel 9.0! This LTS release is the culmination of some multi-year efforts to lay the groundwork for a healthier Bazel ecosystem, and we're excited to see these efforts finally land. Read the full release notes for Bazel 9.0.

Highlights

Bzlmod fully replaces WORKSPACE

Back in 2021, we introduced Bzlmod, a package manager for Bazel intended to replace the WORKSPACE system. In the past few years, Bzlmod has gained a lot of traction in the community, and has become the default external dependency management system in Bazel.

In Bazel 8.0, we disabled the legacy WORKSPACE system by default; and in 9.0, we've completely removed the code supporting WORKSPACE. This enabled us to clear out age-old tech debt and implement some shiny new features with much greater ease, including a local repo contents cache and an experimental remote repo contents cache (thanks to Fabian Meumertzheim!).

But we know the work isn't over; migration is hard, and many users are still on the old WORKSPACE system. To help with migration, we've developed a Bzlmod migration tool and an agent-driven migration setup. They won't magically complete the migration for you, but will hopefully help you get started and continue to iterate.

Starlarkification has landed

Bazel started out with many language rulesets built in. These rules were written in Java and used private APIs, whereas custom rulesets were written in Starlark and used a more limited set of public APIs. To remove this inconsistency, further enable custom rulesets with more powerful APIs, and ease maintenance of the various rulesets, we started the Starlarkification effort, with the goal of moving built-in rulesets out of Bazel into their own modules written in Starlark.

In Bazel 8.0, we moved most built-in rules into their own modules; and in 9.0, we've completed the migration with the removal of built-in C++ rules into rules_cc. Bazel now ships with a lean core with rich APIs, and all previously built-in language-specific rulesets are now shipped separately and can be updated independently from a Bazel release. (A small number of language-specific flags, actions, and toolchain types remain in Bazel for now.)

In 8.0, we introduced the --incompatible_autoload_externally flag to ease migration. With this flag, previously built-in rulesets that are now external modules could still be used as if they were built-in. In 9.0, this flag is empty by default, which means that all rulesets have to be explicitly loaded from external modules. We will remove this flag in 10.0.

Prebuilt protobuf compiler

A long-standing complaint among Bazel users is the need to frequently rebuild the protobuf compiler for seemingly no reason. In Bazel 9, the version of protobuf used by all Bazel builds will be upgraded to at least version 33.4, which includes support for a prebuilt protobuf compiler. In most cases, users can simply set the --@protobuf//bazel/toolchains:prefer_prebuilt_protoc flag to avoid having to build protoc themselves.

For more information, see the announcement on Protobuf News.

Adopting Bazel 9

As with every major release, Bazel 9 introduces incompatible changes. Most of these have been included in our release notes. However, if you run into any difficulties while upgrading, we encourage you to visit the Bazel 9 migration GitHub discussion to ask for help or contribute your own fixes.

Bazel 6 deprecation

With the launch of Bazel 9, we'll deprecate Bazel 6 according to our release model. We'll no longer be backporting fixes for security and OS compatibility issues to 6.x.

Thanks to community member Mike Bland, however, we were able to publish one last minor release (6.6.0) to fix incompatibilities with macOS Tahoe. Thank you, Mike!

What's next?

There's plenty to look out for on the horizon:

A new Bazel documentation site: Community members Alan Mond and Alex Eagle have been working with the Bazel team to set up a new documentation site powered by Mintlify, following Alan's amazing essay, Bazel Docs: Why It Might Be Time For A Refresh. The site is currently in preview mode at preview.bazel.build; we plan to eventually switch bazel.build to this new website.
A new web UI for Bazel Central Registry: Community member Paul Johnston has developed a new web UI for the Bazel Central Registry, with a more powerful search, views of modules filtered by language and maintainers, and more. The site is currently in preview mode at bcr.stack.build; we plan to eventually switch registry.bazel.build to this new website. A special shoutout to community member Max Goisser, who created the original web UI for the BCR!
Starlark typing: Following feedback from the community, we have been designing and implementing a typing system for Starlark, aiming to help ruleset developers manage the growing complexity of Starlark code. We plan to ship this in Bazel 10.0. Follow the progress at #27370.

And finally, a big thank-you to the entire Bazel community for your support. Whether it was filing issues, contributing code, or discussing ideas, every little bit helped to make Bazel 9 possible. We hope you'll continue to participate and follow along through the usual channels: GitHub Discussions, the Bazel Slack channel, @bazelbuild on X (Twitter), the Bazel blog, and the bazel-discuss mailing list. See you next time!

Postmortem for *.bazel.build SSL certificate expiry

Fri, 16 Jan 2026 00:00:00 +0000

On 2025-12-26, at 07:35 UTC, the SSL certificates for many *.bazel.build domains expired. This resulted in widespread build breakages for many Bazel users, as several crucial domains serve essential functionality used by nearly all Bazel builds. It was reported by users on GitHub, Slack, and the bazel-discuss mailing list. The outage lasted for approximately 13 hours before being resolved.

Impact

The majority of the impact was Bazel builds in CI environments breaking due to the following domains being inaccessible:

releases.bazel.build: This domain hosts Bazel release binaries and serves as the primary source for Bazelisk to fetch specific versions of Bazel. The majority of builds failed immediately at this stage, as CI environments often don't have a Bazel binary cached locally.
bcr.bazel.build: This is the Bazel Central Registry (BCR), which serves metadata Bazel uses to resolve external dependencies. Access to the BCR is required unless the lockfile is up to date and the download cache is primed, the latter of which is often not set up for CI environments.
mirror.bazel.build: This is a mirror that hosts copies of source archives for certain popular Bazel projects. Users who managed to work around the unavailability of the previous two domains could nevertheless be unable to build because of this mirror being down.

Background

The Bazel team at Google operates a number of websites under the bazel.build domain. These domains are backed by various underlying systems; for example, bazel.build itself is currently hosted on the same backend that powers the Google Developers site, and registry.bazel.build is currently hosted on GitHub Pages.

Most other subdomains (including releases, bcr, and mirror) are hosted on Google Cloud Platform (GCP). They each statically serve files from a Google Cloud Storage (GCS) bucket, and share a Compute Engine Google-managed SSL certificate. These are the subdomains impacted by the outage.

A Google-managed SSL certificate is set up to cover a list of domains, and is valid for 90 days. About one month before expiry, an auto-renewal process triggers, which checks the validity of each of the domains it covers and provisions a renewed certificate. Crucially, every domain needs to be reachable before the renewed certificate is provisioned.

Timeline of outage

All times are UTC unless otherwise noted.

On 2023-02-23, a new Google-managed SSL certificate was set up to cover all GCP-hosted *.bazel.build domains, including releases, bcr, mirror, and docs-staging.bazel.build. The certificate then went on to auto-renew successfully for the next 2+ years.
On 2025-10-30, a change was submitted to our DNS records to remove the docs-staging.bazel.build subdomain, which was no longer used.
Around 2025-11-26, the auto-renewal process for the Google-managed SSL certificate kicked off. This process went on to fail repeatedly due to docs-staging.bazel.build no longer being accessible. However, these failures never triggered any notifications.
[Outage start] On 2025-12-26, at 07:35:39, the certificate expired. Affected Bazel builds immediately started failing.
At 09:00, a user reported build breakages to the Bazel Slack server. At 09:01, a user filed an issue on Bazel's GitHub repo.
At 12:15, a Bazel team member based in Munich noticed the GitHub issue and posted a message in the team chat group. The team member was out of office and could not help investigate.
At 15:08 (10:08 Eastern Time), a Bazel team member based in New York started investigating.
In the next few hours, two more team members based in New York joined the investigation and attempted various mitigation approaches, initially without success.
[Outage end] At 20:31, a new SSL certificate was finally set up and propagated to all necessary frontends. Access to all affected domains was restored.
At 20:32, the resolution was communicated to users on GitHub, Slack, and the bazel-discuss mailing list.

What went wrong

No alerting
- The Google-managed SSL certificate renewal failures did not trigger any notifications.
- Moreover, the Bazel team didn't have alerting set up for SSL certificate expiry, despite a previous similar outage having left an action item to set up alerts. The action item remained unprioritized and unaddressed until this outage.
Unfortunate timing and lack of expertise
- The outage happened during the winter holidays, when many Bazel team members (including the entire team based in Munich, where Dec 26th is a public holiday) were on vacation. The outage also happened at 2am in New York, way before any team members started working.
- Only a small fraction of team members were familiar with the infrastructure used to manage the bazel.build domain, and the team member with the most expertise was completely unavailable. Other teams whose expertise might have been helpful were also mostly OOO, so we had to investigate on our own.
Outdated or insufficient documentation
- The Bazel team's internal documentation for managing SSL certificates included instructions to set up a manual certificate in case of emergency, but this turned out to be a red herring as this manual certificate system had already been deprecated. The instructions also involved requesting a specific permission that only some team members on vacation could grant, which led to more wasted time.
- The documentation did not mention that deleting a subdomain's DNS records required creating a new Google-managed certificate, nor were there any automated checks in place to keep these in sync.
Poor error messaging and GCP complexity
- When a new Google-managed certificate is set up but fails to provision, it provides no error message to suggest why the provision failed. The GCP documentation offers a troubleshooting page that lists a number of potential failure modes, which meant that the incident responders had to investigate every single one.
- In the end, it turned out that the new SSL certificate had to be associated with both IPv4 and IPv6 "target proxies".
Slow provisioning process
- SSL certificates naturally take a long time (up to 45 minutes) to provision and propagate. Coupled with the trial-and-error nature of the investigation, this time cost had to be paid repeatedly, lengthening the duration of the outage.
- What made this more confusing was that the provisioning had transient states of failure: the provisioning process could report a state of FAILED_NOT_VISIBLE but still return to ACTIVE after as many as 30 minutes. This made it very difficult to tell how long we had to wait.

Where we got lucky

Despite not being perfect, the documentation from the previous similar outage was immensely helpful for the resolution of the new outage.
Many community members stepped up to offer mitigation strategies, including @AliDatadog, @lshirui, and @blackliner. (See also "Recommendations for Bazel users" below.)

Next steps

To prevent similar outages from happening in the future, we're taking the following steps:

Set up alerting: We have set up a GitHub Actions workflow to detect when SSL certificates are nearing expiry and file issues (example) to notify Bazel team members. We're also looking into setting up a prober to report general access issues with resources.
Improve internal documentation and automation: We've removed the outdated instructions from our internal documentation. Changes to add or remove DNS records will now require creating a new Google-managed SSL certificate with a matching domain list.
Recommendations for Bazel users: We've updated our recommendations for Bazel users to insulate themselves from potential outages of this kind. This includes properly populating the download cache and ensuring the lockfile is up to date in CI environments, and hosting internal mirrors for Bazel release binaries, BCR metadata, and source archives.

BazelCon 2025 Recap: Recordings and Birds of a Feather Session Notes

Mon, 08 Dec 2025 00:00:00 +0000

Autumn is BazelCon season, and this year was no different: Last month we hosted BazelCon 2025 together with the Linux Foundation and our sponsors.

We were able to welcome 331 attendees from 214 organizations to Atlanta, Georgia. The conference kicked off with a day of sponsored sessions on Sunday, followed by two days filled with conference talks, birds-of-a-feather sessions and multiple unconferences.

If you want to learn more, you can take a look at the post-event report, browse through some photos, watch the recordings of the main stage talks or read through the birds-of-a-feather notes linked below.

A heartfelt "thank you" goes out to everyone who made this BazelCon another great success: the Linux Foundation, our sponsors, our amazing presenters and all the attendees. We're looking forward to seeing all of you again in 2026!

Recordings

You can find the recordings on our new @BazelCon channel (full playlist):

Sunday, November 9, 2025

Monday, November 10, 2025

Tuesday, November 11, 2025

If you are interested in presentation slides, you can find them attached to the schedule.

Birds of a Feather notes

Unconference notes

Types on Starlark

Bazel Q3 2025 Community Update

Tue, 07 Oct 2025 00:00:00 +0000

Announcements

BazelCon 2025

We're just a few weeks away from BazelCon 2025, and we can't wait to see you in Atlanta! Before the big event, we want to share a few important updates and reminders.

A Special Thanks to Our Sponsors

BazelCon 2025 is free to attend, and that's all thanks to the incredible support from our sponsors. Their generosity makes it possible to bring the community together for two days of learning, networking, and collaboration.

Seven sponsors are supporting the event this year. We'd like to extend a huge thank you to BuildBuddy, EngFlow, Google, Aspect Build, Buildkite, JetBrains, Tweag and VirtusLab for their continued support.

Monday After-Hours Socializing

Join us for more networking and fun after the final sessions of Day 1! BuildBuddy is sponsoring an evening Happy Hour, while EngFlow and JetBrains bring the fun with a Game Night. Make sure to save the date for good drinks, great conversation, and some friendly competition.

Exact times and locations are coming soon! Find all the final details by keeping up with the #bazelcon channel on Bazel Slack, our Bazel X account @bazelbuild, and meetup.build for specific Game Night information.

Hackathon Alert

Extend your BazelCon experience by joining Aspect Build for a special hackathon on Wednesday, November 12th! This post-conference event will be held at the Omni Hotel, the same venue as the conference. It's a great opportunity to roll up your sleeves, collaborate with fellow Bazel enthusiasts, and build something cool!

A Note on Registration

As BazelCon is a free event with limited capacity, we kindly ask the attendees that if your plans have changed and you're no longer able to attend in person, please consider canceling your registration through the event website. This will free up a spot for someone else who is eager to join us. Your cooperation is greatly appreciated and helps us accommodate as many people as possible!

Thank You to Our Speakers

A massive thank you to everyone who submitted a proposal for BazelCon 2025! We were truly impressed by the quality and quantity of submissions. Your willingness to share your knowledge and passion for Bazel is what makes this event so special.

Congratulations to all the speakers whose talks have been accepted! The final schedule has already been announced and we can't wait for you to share your insights with the community.

Get ready for some fantastic talks and Birds of a Feather sessions - we look forward to seeing you all in November!

Attestation Support in BCR

The Bazel Central Registry (BCR) now has enhanced security metadata with attestation support. This significant update, a collaborative effort between Aspect Build, the BCR team, and the Google Open Source Security Team, improves the software supply chain by enabling module maintainers to publish signed provenance with their releases. For those using Bazel modules, this means you'll have more security information to help you make informed decisions about your dependencies. To learn more about this new feature and how it can benefit you, check out the full article by Appu Goundan and Florian Weikert on the Bazel blog.

Product Updates

Upcoming Bazel releases

The first release candidate of Bazel 9.0 will be cut on 2025-10-27. If you want to make sure your feature lands in 9.0, please add it to the release blocker milestone.

Bazel 8.5.0 is expected to release on 2025-11-10. Please send cherry-pick PRs against the release-8.5.0 branch before the RC1 cutoff on 2025-11-03.

Bazel 7.7.0 is expected to release on 2025-10-20. Please send cherry-pick PRs against the release-7.7.0 branch before the RC1 cutoff on 2025-10-13.

Q3 releases

8.4.0 was released in September ‘25, followed by patches 8.4.1 and 8.4.2.

Community Corner

Get Involved: Community Updates & Participation Opportunities

We're bringing you a few updates from the Bazel community, courtesy of Alex Eagle, highlighting new initiatives that are making Bazel easier to use and contribute to.

A new foundation in the works

A new foundation is being created at the Linux Foundation to fund work on OSS Bazel rules. If your company relies on community-driven projects—like bazel-contrib—consider asking your manager to contact your company's OSPO about joining as a founding member. Investment here translates directly into better, more reliable Bazel rules for everyone.

A new home for Bazel Documentation

Rules Authors SIG is funding a new hosting solution for Bazel's documentation site. The prototype is at a placeholder domain: bazel.online. The SIG is currently determining it has parity and meets Google's requirements. If launched, this will give the community the ability to preview changes to the docs, and should enable better ongoing maintenance. You can participate and keep an eye on the development in the #documentation channel on Bazel Slack.

More features in the Bazel Central Registry (BCR)

registry.bazel.build just got two key feature additions that improve discoverability and transparency:

Starlark API Docs: The registry can now show Starlark API documentation for modules that publish docs with their releases. For an example, check out https://registry.bazel.build/modules/jq.bzl. You can learn how to publish your own docs by reading the guide on the Aspect blog.
Deprecation Flags: Modules that are deprecated or come from an archived GitHub repository will now be clearly indicated with a warning sign.

JetBrains’* new Bazel plugin

JetBrains announced the general availability of their their new Bazel plugin for IntelliJ IDEA, PyCharm and Goland in July on the IntelliJ IDEA blog: https://blog.jetbrains.com/idea/2025/07/bazel-ga-release/.

Key features now include Go and Python support, and options to enable faster indexing. JVM language support has been reworked from the ground up to offer more accurate highlighting, completions and refactoring. Additionally, Windows compatibility has been improved and full editing features are now available for Starlark, .bazelproject, .bazelrc, and .bazelversion files.

JetBrains is continuously updating the Bazel plugin documentation pages, which now feature a "Get started with Bazel" tutorial.

Meetup.build

If you enjoy meeting fellow build enthusiasts in person, we encourage you to keep an eye on meetup.build - the right place to find build community meetups and opportunities to learn and share knowledge.

Upcoming meetups:

Munich Build Meetup: October 13th
London Build Meetup: February 2026
New York Build Meetup: March 2026

Articles

Understanding Bazel remote caching - by Julio Merino
Bazel and action (non-) determinism - by Julio Merino
Separating builds for different configs with Bazel - by pikoTutorial
Solving Monorepo Hell with Bazel: A Deep Dive into Modern Build Systems - by Erfan Mohebi
Migrating Airbnb’s JVM Monorepo to Bazel - by Thomas Bao
The 'outside of Bazel' pattern - by Alex Eagle @Aspect Build
Bazel Knowledge: transition with style - by Farid Zakaria
Bazel Knowledge: Testing for clean JVM shutdown - by Farid Zakaria and more at fzakaria.com
Embedded bare-metal C with Bazel and AVR - by Uros Popovic
Simple Lua integration in Go - by Uros Popovic and more at popovicu.com
Tutorial: Get started with Bazel - by JetBrains
Understanding Apple Debug Info - by Keith Smiley
How to Build Python Code with Bazel (and Why) - by Ohad Ravid

Videos

What is Bazel? A Beginner’s Guide for 2025 - by Vitaly Bragilevsky
Bazel - Marcus Boerger - ACCU 2025 - talk given by Marcus Boerger at the ACCU Conference
Bazel for Everyone? Hard Questions with Confluent Engineers - by Alex Eagle @Aspect Build
Better Bazel Flag Defaults with Markus Hofbauer - by Alex Eagle @Aspect Build
Bazel Training 101 - playlist by Alex Eagle @Aspect Build
IDE Support for Bazel: JetBrains’ New Plugin with Justin Kaeser - by Alex Eagle @Aspect Build
How Tinder built and open-sourced Bazel-diff to transform their CI/CD at scale - by BuildKite
State of Swift and iOS in Bazel with Luis Padron and Brentley Jones - by Alex Eagle @Aspect Build
How Snowflake Transformed its C++ and Java Build Systems with Julio Merino - by Alex Eagle @Aspect Build

Resources

GitHub repository: https://github.com/bazelbuild/bazel
Releases: https://github.com/bazelbuild/bazel/releases
Slack chat: https://slack.bazel.build
Google group: bazel-discuss@googlegroups.com
Special Interest Groups (SIG):

Reach out the email(s) listed below if you’d like to be added to the SIG calendar invites.

SIG	Meeting frequency	Point of contact
Rules authors	Every two weeks	bazel-contrib@googlegroups.com
Android app development	Monthly	ahumesky@google.com
Bazel plugin for IntelliJ	Monthly	messa@google.com
Remote execution API working group	Monthly	chiwang@google.com
Supply chain security / SBOM	Weekly	fwe@google.com

Interested in learning about SIGs or starting a new one? Find more information on our website.

Want to get your SIG listed? Please add it to the Community repository.

Ideas, feedback, and submissions are welcome!

Thanks,

Google Bazel team

Enhancing Security Metadata in BCR with Attestation Support

Fri, 01 Aug 2025 00:00:00 +0000

Bazel Central Registry is the go-to source for discovering and managing Bazel modules. Over the last few months Aspect Build, Bazel Central Registry and the Google Open Source Security Team have been working together on enhancing the security of the software supply chain. We are happy to announce that attestation support in BCR is now available. This includes updated GitHub Actions for packaging and releasing rulesets. It also enables pre-submit verification of this new security metadata on the registry.

For module maintainers this allows easy publishing of signed provenance with module releases. For consumers, this means a greater availability of security metadata to make informed decisions when including or updating dependencies.

Get Started Today

Publishing Attestations

If you are using release_ruleset with the publish-to-bcr legacy app to publish your modules to BCR, you should:

upgrade your release_ruleset to use the new attestation generating workflow
follow the instructions to setup the new publish-to-bcr workflow

To see how this affects a release, let's use the example of aspect_rules_lint which has been publishing modules with attestations since v1.3.4. You will see a new publishing artifact `attestations.json' that contains information about your attestations. On successful publication, BCR will preserve and mirror attestations for publishing artifacts. Please note that since BCR does not mirror the source archive, it also does not mirror the source archive's attestation. The BCR UI will attach a blue indicator to a release version informing users that attestations are available for consumption.

Verifying Attestations

Once you've generated and published your attestations, you can validate them. For the purposes of this example, we will once again use aspect_rules_lint. There are three critical files to attest to cover a module version:

MODULE.bazel (published to BCR)
source.json (published to BCR)
the packaged module source (not hosted on BCR): rules_lint-v1.3.4.tar.gz

Keep in mind that attestations for MODULE.bazel and source.json are generated by the publishing workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml and attestations for the source archive are generated by the release workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml. We need these workflow references when verifying the attestations.

Verify MODULE.bazel

Let's try to validate MODULE.bazel. To illustrate this, we'll do it by hand, though your build infrastructure should automate it. On the command line you can do this using the GitHub CLI.

The GitHub CLI uses attestations that were uploaded to the attestations store during publication. The attestation can be seen in the attestations tab for a project.

Download the file from BCR

$ curl -sSO https://bcr.bazel.build/modules/aspect_rules_lint/1.3.4/MODULE.bazel

Run the GitHub CLI attestation verification workflow

$ gh attestation verify MODULE.bazel \
    --repo aspect-build/rules_lint \
    --source-ref refs/tags/v1.3.4 \
    --signer-workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml@refs/tags/v0.0.1

Loaded digest sha256:e0758f32323887cfe0b9d6e9f01f803f50a3f5efb6a229fc6791e99bd91ea038 for file://MODULE.bazel
Loaded 1 attestation from GitHub API

The following policy criteria will be enforced:
- Predicate type must match:................ https://slsa.dev/provenance/v1
- Source Repository Owner URI must match:... https://github.com/aspect-build
- Source Repository URI must match:......... https://github.com/aspect-build/rules_lint
- Source repo ref must match:............... refs/tags/v1.3.4
- Subject Alternative Name must match regex: ^https://github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml@refs/tags/v\*
- OIDC Issuer must match:................... https://token.actions.githubusercontent.com

✓ Verification succeeded\!

The following 1 attestation matched the policy criteria

- Attestation \#1
  - Build repo:..... aspect-build/rules_lint
  - Build workflow:. .github/workflows/release.yml@refs/tags/v1.3.4
  - Signer repo:.... bazel-contrib/publish-to-bcr
  - Signer workflow: .github/workflows/publish.yaml@refs/tags/v0.0.1

The --source-ref refs/tags/v1.3.4 flag ensures the build came from an officially tagged commit.

The --signer-workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml@refs/tags/v0.0.1 flag corresponds to the approved builder workflow and version. While it is optional for verification, it's recommended to ensure the official publishing workflow was used. For a builder with many versions this can be a regex like ...@refs/tags/v\\d+\\.\\d+\\.\\d+$, but your build's policy file can map the correct version to the artifact in question.

Verifying source.json

Repeat the process used for MODULE.bazel with source.json

$ curl -sSO https://bcr.bazel.build/modules/aspect_rules_lint/1.3.4/source.json
$ gh attestation verify source.json \
    --repo aspect-build/rules_lint \
    --source-ref refs/tags/v1.3.4 \
    --signer-workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml@refs/tags/v0.0.1

Verifying source archive attestations

Verification of source archives needs a minor tweak to --signer-workflow since they are generated by a different builder: github.com/bazel-contrib/.github/blob/master/.github/workflows/release_ruleset.yaml. The source archive is also not mirrored or hosted by BCR, so it must be downloaded from the project's release archives.

$ curl -sSLO https://github.com/aspect-build/rules_lint/releases/download/v1.3.4/rules_lint-v1.3.4.tar.gz
$ gh attestation verify rules_lint-v1.3.4.tar.gz \
    --repo aspect-build/rules_lint \
    --source-ref refs/tags/v1.3.4 \
    --signer-workflow github.com/bazel-contrib/.github/.github/workflows/release_ruleset.yaml@refs/tags/v7.1.0

Verifying with a downloaded attestation

You can skip the github attestation store lookup and use a downloaded attestation instead. For example, with MODULE.bazel:

Download the file from BCR and its attestation

$ curl -sSO https://bcr.bazel.build/modules/aspect_rules_lint/1.3.4/MODULE.bazel
$ curl -sSO https://bcr.bazel.build/modules/aspect_rules_lint/1.3.4/MODULE.bazel.intoto.jsonl

Use the --bundle flag to run the verification workflow with the downloaded attestation

$ gh attestation verify MODULE.bazel \
    --repo aspect-build/rules_lint \
    --source-ref refs/tags/v1.3.4 \
    --signer-workflow github.com/bazel-contrib/publish-to-bcr/.github/workflows/publish.yaml@refs/tags/v0.0.1 \
    --bundle MODULE.bazel.intoto.jsonl

Limitations

If you want to publish your module to BCR, you must use attestations generated by the community Github Actions Workflows defined in release_ruleset and publish.
If you are using your own actions and attestations generators, BCR may reject your release. You can still generate attestations for them, but your release may not include them via the publish action (set attest:false on publishing)

What's Next?

The work on Bazel attestation support in the BCR is ongoing and as this capability matures, we can expect to see:

Broader support for different attestations types and sources which is currently limited as we work out any issues with the build and publishing flows.
Increased adoption leading to strong policy decisions as more of a developers dependency tree is accompanied by attestations.
Further improvements to the tools for generating and verifying attestations making it easier for maintainers and users to benefit from this feature.
Deeper integration into Bazel to allow first class support for attestations.

We encourage module maintainers to explore integrating attestation generation into their release workflows and for Bazel users to start leveraging the available tools to verify the attestations of their dependencies. This collaborative effort is key to building a more resilient and trustworthy software supply chain with Bazel.

Acknowledgements

The Aspect Build team (@kormide, @alexeagle) for their work on improving release processes for Bazel developers and specifically on the reusable actions for producing the secure SLSA attestations with these reusable workflows.

The extended BCR team (@meteorcloudy, @adincebic) for their work validating and mirroring attestations on BCR making them easily available for consumption.

The SLSA team (@ramonpetgrave64) for their work ensuring we were producing our SLSA attestations that allowed higher level audits on build processes.

Bazel Q2 2025 Community Update

Fri, 04 Jul 2025 00:00:00 +0000

Announcements

BazelCon 2025

We’re excited to invite you to BazelCon 2025 in Atlanta, Georgia! Join the amazing Bazel Community for two days of talks, Birds of a Feather sessions, and networking, all focused on the Bazel build system. Thanks to our generous sponsors, the event is completely free to attend.

This year, we’re also offering a special Community Training Day on November 9th to help you deepen your expertise. Check the schedule and see what Aspect Build, EngFlow and Tweag have in store for you!

Don’t miss this chance to learn, share, and connect—register through the BazelCon website*.

Venue: Omni Hotel, Atlanta, Georgia
9th November: Community Training Day
10-11th November: BazelCon

Accomodation: This year, BazelCon is hosted alongside KubeCon + CloudNativeCon. Our attendees can book chosen hotels at these events Venue+Travel tab, benefiting from the room block and fixed prices. Please note, rooms will most likely sell out in advance of the room block close dates listed on the website. We advise you to book early to secure a room at the conference rate.

*As BazelCon is a free event with a limited capacity, we encourage everyone to be thoughtful about their registrations. If it becomes apparent you will not be able to join us, please cancel your attendance to give others an opportunity to attend.

Call For Proposals

If you have insights, projects, or practical experiences with Bazel that could benefit the community, we invite you to submit a proposal for BazelCon 2025. Talks and Birds of a Feather sessions are all welcome. Your contributions can help spark meaningful discussions and knowledge sharing among peers. If you’re interested in presenting, please fill out our Call for Proposals form. We look forward to your submissions - CFP closes August 10th!

BazelCon talk recordings 2017-2024 now available on Linux Foundation Channel

Per popular request, we have moved all past BazelCon recordings to the Linux Foundation YouTube channel. The previous channel that hosted these has been hidden, which resulted in the videos not showing up in search. This has now been fixed and you can access all playlists through the LF channel, as well as searching for them by name in the search bar.

Product updates

Bazel 8.4.0 release branch is now open. Please send cherry-pick PRs against this branch if you'd like your change to be implemented, and follow the release tracking issue for updates.

Q2 releases

Bazel 8.2.0 was released in April ‘25, followed by patch 8.2.1.
Bazel 8.3.0 was released in June ‘25, followed by a patch 8.3.1.

Community Corner

JetBrains’* new Bazel plugin coming soon

The Bazel plugin team at JetBrains is preparing their new Bazel plugin for IntelliJ IDEA, PyCharm and Goland for general availability later in July, together with the 2025.2 release of IntelliJ IDEA. Compared to the old plugin originally developed by Google, the new plugin features a closer integration with the IntelliJ IDEA project model, allowing more accurate highlighting, completions and refactoring in JVM languages, as well as many smaller usability improvements. The GA release will additionally support Python and Go targets. A full release announcement will be posted on the IntelliJ IDEA blog when it becomes available.

JetBrains’ Bazel Plugin 2025.1 for IntelliJ IDEA

The recent updates to JetBrains' Bazel Plugin for IntelliJ IDEA, culminating in the 2025.1 release, bring a range of improvements, rolled out by JetBrains incrementally over recent months, aim to make working with Bazel projects inside IntelliJ IDEA more efficient.

Some enhancements include:

Full Bazel 8 & nested modules support: Seamlessly work with the latest Bazel features and complex project structures.
Experimental phased sync: Drastically reduces initial sync times, letting you start coding and browsing almost instantly, leaving heavier tasks happening in the background.
Python & Scala support: Full IDE experience for these languages, including run and debug, as well as code assistance and syncing targets.
Smart dependency management: Quickly add missing dependencies directly from code.
Enhanced Starlark support: Better in-editor documentation and smarter code completions for BUILD files.
Improved test workflows: Debug and run tests with coverage directly within the IDE.
Streamlined navigation & setup: Easier access to targets, improved search, and quick-start project templates.
Project admin tools: Features like "shard sync" and managed .bazelproject for large-scale consistency.

For a deeper dive on these and more features, visit Justin Kaeser’s article here.

A few words from JetBrains on Bazel for IntelliJ and CLion Plugin Updates

‘’Starting from the second week of July, the plugins will officially support the 2025.2 version of JetBrains IDEs. This also means that support for 2024.3 is no longer maintained, and the final released plugin version for 2024.3 is 2025.06.10.0.1.

We apologize for the various Bazel execution-related issues in the versions released in March and April. Huge thanks to everyone who provided feedback in the #intellij channel on Bazel Slack and on the plugin’s GitHub page. Versions 2025.05.13.0.1 and later include fixes that address the reported regressions.

C++ Support Updates

Over the past year, we have improved C++ support in the plugin, including cc_toolchain support for code analysis, and added MSVC support on Windows. Feel free to read the article on the JetBrains blog about the new features of the plugin: https://jb.gg/bazel-clion-2025.

We received some feedback about issues with CLion Nova and the Bazel plugin, resulting in the “Processing XXX file changes” dialog appearing and becoming stuck. The issue was indeed in the CLion Nova engine (CPP-44506) and was fixed in CLion 2025.1.2. However, manual cache invalidation is required on the user side via the “Invalidate Caches” action in CLion.

Starting from version 2025.06.24.0.1, the Bazel for CLion plugin includes additional fixes for performance issues with the same user-visible symptom (“Processing XXX file changes”). This version will be available on JetBrains Marketplace in the second week of July. Please note that the same cache invalidation action is required after the upgrade.’’

Build Meetup in Munich - Recap

The Build Meetup in Munich, co-hosted by EngFlow and JetBrains, brought together build system professionals for a valuable evening of insights. Discussions covered everything from Bazel fundamentals and advanced configuration management to handling large datasets, optimizing C/C++ dependencies, and even building an entire Linux OS with Bazel. The meetup also explored the complexities of remote execution, emphasizing the balance between customization and automation. For a deeper dive into some of the slides and takeaways, go to the full article!

Articles

Securing Bazel's Module Registry - by Alex Eagle @Aspect Build
Bazel's Original Sins - by Farid Zakaria
Bazel Knowledge: Homonymous Bazel Modules - by Farid Zakaria
And many more, on fzakaria.com
Dagger and Bazel - by Chris Chinchilla @Aspect Build
Gojek’s Journey to 3x Faster iOS Builds with Bazel - by Sanju Naik
Migrating to Bazel Modules (a.k.a. Bzlmod) - Toolchainization - by Mike Bland @EngFlow
Migrating to Bazel Modules (a.k.a. Bzlmod) - Repo Names, Again… - by Mike Bland @EngFlow

Videos

Using Bazel for C++ development and more - talk by Evgenii Novozhilov
Easy Build with Bazel - video playlist by Byte Anatomy
The Hidden Cost of Bazel with Alex Eagle from Aspect Build - by Ankit Jain @Aviator
How we made CLion understand your Bazel Project - talk by Daniel Brauner
Production-Ready C++ with Bazel - by Alex Eagle @Aspect Build
Developer Tooling in Monorepos with bazel_env - feat. Fabian Meumertzheim - by Alex Eagle @Aspect Build
Getting Started with Angular 20 in a Bazel Monorepo - by Alex Eagle @Aspect Build

Resources

GitHub repository: https://github.com/bazelbuild/bazel
Releases: https://github.com/bazelbuild/bazel/releases
Slack chat: https://slack.bazel.build
Google group: bazel-discuss@googlegroups.com
Special Interest Groups (SIG):

Reach out the email(s) listed below if you’d like to be added to the SIG calendar invites.

SIG	Meeting frequency	Point of contact
Rules authors	Every two weeks	bazel-contrib@googlegroups.com
Android app development	Monthly	ahumesky@google.com
Bazel plugin for IntelliJ	Monthly	messa@google.com
Remote execution API working group	Monthly	chiwang@google.com
Supply chain security / SBOM	Weekly	fwe@google.com

Interested in learning about SIGs or starting a new one? Find more information on our website.

Want to get your SIG listed? Please add it to the Community repository.

Ideas, feedback, and submissions are welcome!

Thanks,

Google Bazel team

Bazel Q1 2025 Community Update

Thu, 10 Apr 2025 00:00:00 +0000

Announcements

10th Anniversary of Bazel’s Public Launch

We have gone a long way since we first said ‘’Hello World’’. Reflecting on this milestone, we just want to say thank you to all of you—our users, contributors, and the amazing community—who’ve been a part of this journey. Whether you’ve been with us since the beginning or joined along the way, your support, feedback, and collaboration have shaped Bazel into what it is today. Thank you for 10 years together!

Q4 2024 - Bazel 8 and BazelCon

In December, we launched Bazel 8, making a big step towards a better and more efficient build experience for our users. The community has played a great role in shaping 8.0, with every bug report, code contribution and improvement discussions.

You can learn more at -

Bazel 8.0 LTS - blog post with all highlights of this release
Release notes - for a deeper dive

In November, we had the pleasure of co-hosting the community at BazelCon in California. With two days jam packed with exceptional talks, Birds of a Feather sessions and after-hours discussions, it was an unforgettable experience.

The event was so amazing, and we are already planning to do it all over again in 2025!

Bazel User Survey

Thank you to everyone who took the time to fill out our 2025 user survey. We've read through all your feedback, and while most of you seem to be pretty happy with Bazel, we definitely hear your concerns and we're committed to making things even better.

You can find the survey result at Bazel User Survey Results 2025.

Your feedback is incredibly valuable, and it helps us prioritize improvements for Bazel. We're grateful for your support and patience as we move forward. Stay tuned for upcoming updates!

BCR Module growth

Since the release of Bazel 8, the Bazel Central Registry (BCR) has seen a significant increase in modules, growing from approximately 500 to over 650. This growth reflects the active contributions from the Bazel community, for which we are deeply grateful.

To help Bazel grow further, check out the list of top wanted modules! By contributing a module, you’re not only sharing your knowledge but also helping others save time, solve problems, and innovate faster.

Product Updates

Bazel 9 roadmap

We've shared our roadmap for 2025, with planned features for the Bazel 9 release at the end of the year. Notable items include deprecation of WORKSPACE functionality, Starlarkification of C++ rules and removal of autoloads, lazy evaluation of symbolic macros, and a new project-based model to reduce the cognitive burden introduced by Bazel flags. Let us know what you think!

Releases

Bazel 8.2 is in progress, with the 3rd release candidate released in early April. Please follow the release tracker for updates and get your cherry-picks in by the cut-off dates.

Recap of Q1 releases:

Bazel 7.6 was released in March ‘25.
Bazel 8.1 was released in February ‘25, along with patch 8.1.1.
Bazel 7.5 was released in January ‘25.

Community Corner

Build Meetups

22nd May - London Build Meetup Jane Street

Articles

Bazel Knowledge: Be mindful of Build Without the Bytes (bwob) - Farid Zakaria
Bazel: Build Event Protocol Viewer - Farid Zakaria
Fast and Reliable Builds at Snowflake with Bazel - Julio Merino
Unusual Builds with Bytes - Son Luong Ngoc @BuildBuddy
Troubleshooting Bazel with Git Bisect - Son Luong Ngoc @BuildBuddy
Migrating to Bazel Modules (a.k.a. Bzlmod) - Module Extensions - Mike Bland @EngFlow
Migrating to Bazel Modules (a.k.a. Bzlmod) - Fixing and Patching Breakages - Mike Bland @EngFlow
Beautiful CI for Bazel - Hariom Narang Videos
Advanced Build Tools and Remote Execution API - Son Luong Ngoc @BuildBuddy
Writing Your Own BUILD Generator in Starlark - Alex Eagle @Aspect

Resources

GitHub repository: https://github.com/bazelbuild/bazel
Releases: https://github.com/bazelbuild/bazel/releases
Slack chat: https://slack.bazel.build
Google group: bazel-discuss@googlegroups.com
Special Interest Groups (SIG):

Reach out the email(s) listed below if you’d like to be added to the SIG calendar invites.

SIG	Meeting frequency	Point of contact
Rules authors	Every two weeks	bazel-contrib@googlegroups.com
Android app development	Monthly	ahumesky@google.com
Bazel plugin for IntelliJ	Monthly	messa@google.com
Remote execution API working group	Monthly	chiwang@google.com
Supply chain security / SBOM	Weekly	fwe@google.com

Interested in learning about SIGs or starting a new one? Find more information on our website.

Want to get your SIG listed? Please add it to the Community repository.

Ideas, feedback, and submissions are welcome!

Thanks,

Google Bazel team

Bazel 8.0 LTS

Mon, 09 Dec 2024 00:00:00 +0000

We're pleased to announce the release of Bazel 8.0!

This LTS release marks a significant step forward for Bazel, offering a more streamlined and efficient build experience. With Bzlmod as the default for dependency management and major rulesets fully migrated to Starlark, Bazel 8.0 empowers you to build with greater speed and flexibility. This release also includes a number of bug fixes, performance enhancements, and new features to improve your workflow.

Read on to explore the key highlights of Bazel 8.0, and be sure to check out the full release notes for a complete overview of the changes.

Bazel 8 key highlights

Starlarkification: modularization of rules

A significant change in Bazel 8.0 is the ongoing effort to modularize rules using Starlark. Many rules previously bundled with Bazel are now split into their own modules. This includes rules for Android, C++, Java, Protobuf, and Shell.

Android: All android_* build and repo rules have migrated to rules_android. Android tools are no longer bundled within Bazel.
C++: All C++ toolchain-related symbols have been moved to rules_cc. Other symbols, including the rules themselves, will be moved in a future release.
Java: All java_* rules now reside in rules_java.
Protobuf: *_proto_library rules have been moved to protobuf.
Python: All py_* rules and providers (like PyInfo) have been moved to rules_python.
Shell: All sh_* rules are now part of rules_shell.

To ease this transition, Bazel 8.0 introduces the --incompatible_autoload_externally flag which automatically loads rules from their respective repositories, thus removing the need for an imminent migration. The migration to use load statements needs to happen in 2025 before Bazel 9 is released. Load statements are supported on Bazel versions 6, 7 and 8, so the migration is largely independent of the Bazel version.

Bzlmod: the new default for dependency management

Bzlmod was introduced in Bazel 5 in 2021 as an experimental feature, it became GA in Bazel 6 and turned on in Bazel 7. In Bazel 8, the new powerful external dependencies system works with the old WORKSPACE mechanism turned off by default. This shift means that Bazel no longer automatically reads the WORKSPACE and WORKSPACE.bzlmod files when building your project. These files were previously required for defining external repositories and dependencies, but Bzlmod offers a more modern and efficient approach.

Since Bzlmod was launched, the Bazel Central Registry growth has accelerated from Bazel release to Bazel release:

The BCR now hosts more than 500 Bazel modules with 2500+ different versions.

We encourage all users to migrate to Bzlmod and take advantage of its benefits. Take a look at this migration guide for step-by-step instructions and best practices for moving from the traditional WORKSPACE setup to the streamlined Bzlmod system.

We are aiming to remove all WORKSPACE functionalities in Bazel 9.

Symbolic macros

Symbolic macros offer a new way to write macros that are safer to use and that catch bugs sooner. For example, their arguments are typed like rule attributes, and the author decides which attributes permit select()s based on whether the macro needs to examine that value or pass it through. With Symbolic macros come several related features:

A new macro-aware visibility model, which protects a macro's internal targets from being depended on by its caller
Rule Finalizers, which are macros that can call native.existing_rules() with less surprising behavior
A way for a macro to inherit the attribute schema of another rule or macro that it wraps.

Check out the documentation on macros for more details.

Bazel 5 deprecation

With the launch of Bazel 8.0, we're announcing the upcoming deprecation of Bazel 5.0. Starting January 2025, Bazel 5 will no longer receive critical bug fixes, security updates, or OS compatibility support.

We strongly encourage you to upgrade to Bazel 8.0 to benefit from the latest features, performance improvements, and ongoing support. You can also opt for a rolling release to stay up-to-date with the newest developments at HEAD.

Refer to our release model for more details.

What’s next?

Try out Bazel 8.0! This is a significant release that brings a wealth of improvements. We encourage all Bazel users to explore the new features and migrate to Bazel 8.0 to take advantage of its enhancements. Questions? Want to discuss something specific? File an issue or start a discussion on GitHub so we can take a look.

Stay connected! To stay up-to-date on all things Bazel, read the Bazel blog, join our Slack, follow @bazelbuild on X (Twitter), join the bazel-discuss@googlegroups.com mailing list, or reach out to product@bazel.build. We would love to hear any feedback you may have!

In closing, we’d like to extend our sincere gratitude to the entire Bazel community. Every bug report, code contribution, ruleset improvement, and discussion played a role in shaping Bazel 8.0. Thank you for your continued support and dedication to making Bazel better with every release!

Bazel Blog

Bazel Q1 2026 Community Update

Announcements

Mark Your Calendars: BazelCon 2026 is Heading to Amsterdam!

Call for Proposals

Want to become a Sponsor of BazelCon 2026?

Product Updates

Upcoming Bazel releases

Q4 & Q1 releases

Community Corner

Bazel for CLion plugin updates

BUILD Foundation

Web Updates: Previews for the BCR and Bazel.build

Upcoming Meetup.build events

Community created content

Resources

Ideas, feedback, and submissions are welcome!

Dependabot Now Supports Bazel Version Updates

The Journey to Bazel Support

Why Bazel Support Is Challenging

Built in Partnership with Bazel

How It Works

Getting Started

Try It Out

Bazel 9 LTS

Highlights

Bzlmod fully replaces WORKSPACE

Starlarkification has landed

Prebuilt protobuf compiler

Adopting Bazel 9

Bazel 6 deprecation

What's next?

Postmortem for *.bazel.build SSL certificate expiry

Impact

Background

Timeline of outage

What went wrong

Where we got lucky

Next steps

See also

BazelCon 2025 Recap: Recordings and Birds of a Feather Session Notes

Recordings

Sunday, November 9, 2025

Monday, November 10, 2025

Tuesday, November 11, 2025

Birds of a Feather notes

Unconference notes

Bazel Q3 2025 Community Update

Announcements

BazelCon 2025

Attestation Support in BCR

Product Updates

Upcoming Bazel releases

Q3 releases

Community Corner

Get Involved: Community Updates & Participation Opportunities

JetBrains’* new Bazel plugin

Meetup.build

Articles

Videos

Resources

Ideas, feedback, and submissions are welcome!

Enhancing Security Metadata in BCR with Attestation Support

Get Started Today

Publishing Attestations

Verifying Attestations

Verify MODULE.bazel

Download the file from BCR

Run the GitHub CLI attestation verification workflow

Verifying source.json

Verifying source archive attestations

Verifying with a downloaded attestation

Limitations

What's Next?

Acknowledgements

Bazel Q2 2025 Community Update

Announcements

BazelCon 2025

Call For Proposals

BazelCon talk recordings 2017-2024 now available on Linux Foundation Channel