Philipp Wollermann, a Staff Software Engineer at Google, has extensive experience with Bazel, Google's open-source build system, having worked on it for over eight years. During UnblockConf '21, he discussed the insights gained from implementing Bazel CI on Buildkite, sharing tips to optimize build pipelines. Bazel, developed to address Google's specific challenges, offers fast and reliable builds by incrementally recompiling only necessary files and skipping unchanged tests. Bazel CI, a custom system built on Buildkite, tests and releases Bazel using parallelization and target sharding to reduce build times. Wollermann addressed common issues, such as lengthy build times and large monorepos, recommending solutions like target skipping, multiple pipelines, and remote execution. He emphasized the importance of infrastructure as code for managing pipelines, using Terraform for scalability, and suggested local and remote caching to optimize resource usage. Additionally, he advocated for stateless workers to safely test untrusted code and highlighted Bazel's automatic flaky test detection and retry features to improve test reliability.