Dropbox Collaborates with GitHub to Reduce Monorepo Size from 87GB to 20GB

Dropbox reduced its backend monorepo from 87GB to 20GB — a 77% reduction — by addressing inefficiencies in Git's delta compression and packfile generation. The root cause was not large binaries or bad commits, but suboptimal Git storage heuristics at scale. Engineers collaborated with GitHub to tune server-side repacking parameters including delta window and depth behavior, validating changes in mirrored environments before production rollout. The result: clone times dropped from over an hour to under 15 minutes, CI pipelines improved, and developer onboarding became faster.