Graphite is addressing the challenge of increasing Continuous Integration (CI) costs faced by rapidly scaling companies by introducing a CI optimizer that integrates with Buildkite and GitHub Actions. This tool is designed to manage CI costs effectively when using stacked pull requests (PRs), a method that accelerates code shipping by enabling smaller and more frequent PRs. Stacking PRs, however, demands constant rebasing, which can unnecessarily trigger full rebuilds in CI systems. The CI optimizer allows selective CI runs on specific parts of a PR stack, such as the bottom or top PRs, and differentiates between fast and slow test suites to prevent excessive CI runs. Additionally, batch merges in the Graphite merge queue further minimize unnecessary CI processes. The CI optimizer, currently in private beta, provides flexible configuration options to ensure efficient CI management, with plans for a public beta rollout soon.