Reddit Transforms Mobile Development with Buildkite: Faster Builds, Improved Efficiency, and Enhanced Developer Autonomy
Buildkite Pty Ltd., a leader in scalable software delivery solutions, today announced that Reddit, one of the world’s largest online communities with over 400 million weekly active users, has successfully migrated its mobile continuous integration and delivery (CI/CD) pipelines to Buildkite. This strategic move has delivered significant improvements in build performance, reliability, and developer experience across Reddit’s mobile engineering organization. By adopting Buildkite’s high-performance hosted agents and dynamic pipeline capabilities, Reddit has achieved a 30% reduction in build times for both Android and iOS workflows, near-instant queue times, and streamlined development processes—all while maintaining cost efficiency.
Solving Challenges at Scale
As Reddit’s user base and codebase continued to grow, its mobile engineering teams faced mounting challenges with their previous CI/CD provider. The inability to customize build environments, coupled with configuration complexity, hindered productivity. Engineers were constrained by a lack of support for custom Docker images, which limited flexibility. Additionally, the team grappled with unreliable builds caused by environment drift and dependency failures. Managing 6,000 lines of YAML split across multiple files further compounded the inefficiencies, making it difficult to maintain and scale their CI/CD infrastructure.
Recognizing the need for a more robust and flexible solution, Reddit turned to Buildkite. The migration, which impacted over 200 mobile engineers, involved transitioning both Android and iOS mono-repositories to Buildkite’s platform. Leveraging Buildkite’s composable pipeline primitives, Reddit was able to create custom workflows that seamlessly integrated with tools like Bazel and BuildBuddy. This enabled both iOS and Android apps to be built efficiently on Linux runners using remote execution—a game-changing advancement that simplified workflows and reduced redundancy.
Dramatic Improvements in Build Performance
The results of the migration have been transformative. Comprehensive benchmarking revealed that Reddit’s builds now run up to 30% faster, with job queue times consistently dropping to just five seconds. Key features such as Buildkite’s Git caching and container caching played a pivotal role in these gains. For instance, Git checkout times were slashed from several minutes to just 30-40 seconds—a remarkable improvement that significantly accelerated the development cycle.
Intelligent build cancellation and customizable logging further enhanced operational efficiency and developer experience. These features not only reduced unnecessary resource consumption but also provided clearer insights into build processes, enabling faster debugging and issue resolution.
“With Buildkite, we finally have the reliability and performance at scale that our mobile teams were missing,” said Ken Struys, Reddit’s Director of Developer Experience. “We’ve seen a significant improvement to the overall developer experience, and both Android and iOS CI are more than 30% faster on Buildkite.”
A Lean Migration Process with Zero Risk
Despite the complexity of migrating over 200 engineers and two large mono-repositories, Reddit executed the transition ahead of schedule with a remarkably lean core team. “We built most of the Android pipelines and the iOS pipelines with two people,” noted Struys. “You don’t need massive engineering resources to use Buildkite, but the scale is tremendous. We’ve got 170-plus engineers on it now, and most of our builds are running 12 to 15 jobs in each field.”
The migration was meticulously planned and executed through a staged approach. Shadow builds ran in parallel with production systems to ensure a seamless, zero-risk transition. Throughout the process, Buildkite’s team provided responsive support and delivered tailored feature requests, including a GitHub App for GitHub Enterprise Server, further enhancing the platform’s compatibility with Reddit’s existing tools.
Unlocking Innovation at Scale
Reddit’s successful migration underscores the transformative potential of modern, composable CI/CD architecture. Traditional CI/CD platforms often struggle to meet the demands of rapidly growing engineering organizations, leading to bottlenecks and inefficiencies. Buildkite’s combination of high-performance hosted agents and flexible, composable pipeline primitives addresses these limitations, empowering teams to innovate at the speed their users demand.
“Reddit’s successful migration exemplifies the transformative power of modern, composable CI/CD architecture,” said Dan Ring, Vice President of Product at Buildkite. “When engineering organizations outgrow traditional CI/CD limitations, they need a platform that can deliver both immediate performance gains and long-term scalability. Reddit’s experience demonstrates what’s possible when you combine Buildkite’s high-performance hosted agents with our flexible, composable primitives. This isn’t just about faster builds—it’s about unleashing engineering teams to innovate at the speed their users demand.”
Empowering Developers and Driving Growth
The migration to Buildkite has not only improved technical metrics but also had a profound impact on Reddit’s mobile engineering culture. With faster builds, near-instant queue times, and greater autonomy over their workflows, engineers can now focus more on innovation and less on infrastructure constraints. Dynamic pipelines have eliminated repetitive configurations, allowing developers to iterate quickly and bring new features to market faster.
For Reddit, this transformation is about more than just optimizing CI/CD—it’s about creating a foundation for future growth. As the company continues to expand its global presence and user base, having a scalable, reliable CI/CD platform will be critical to maintaining its competitive edge. Buildkite’s ability to adapt to evolving needs ensures that Reddit’s engineering teams remain agile and equipped to tackle the challenges of tomorrow.
About Buildkite Pty Ltd:
Based in San Francisco and Melbourne, Buildkite is a fast-growing software delivery provider that offers the industry’s first and only Scale-Out Delivery Platform. Buildkite’s Scale-Out Delivery platform is the only solution that provides the flexibility and scale required by the world’s most demanding companies for delivering software across a broad range of use cases, including AI/ML workloads and mobile application development. Global innovation leaders including Airbnb, Block, Canva, Cruise, Culture Amp, Elastic, Lyft, PagerDuty, Pinterest, PlanetScale, Rippling, Shopify, Slack, Tinder, Twilio, Uber, and Wayfair have standardized on Buildkite for software delivery. For more information, please visit www.buildkite.com.
