Discover how to successfully move a Python monorepo from Bazel to Pants in stages.

This post details the migration of a Python monorepo from Bazel to Pants, focusing on improving CI times, developer experience, and reducing build metadata. The migration was phased, starting with formatters and linters, then tests, then binary rules, and finally Docker images. Key technical achievements include dependency inference, changed file detection, and the reduction of Bazel metadata from 19,000 lines to 2,400 lines of Pants metadata, resulting in CI times dropping from 10-12 minutes to under 4 minutes.