Managing Monorepos at Scale: Lessons from Meta, AWS, and a 15-Repo Migration

The article frames monorepo vs. polyrepo as an operating-model choice that shapes velocity, duplication, integration, and coordination at scale.

It contrasts large-scale code organization practices at Meta and AWS, highlighting the tradeoff between discoverability and autonomy.

A weekend migration at SID Technologies moved 15 repositories into one monorepo, showing how cross-cutting changes can get easier while ownership and tooling become more important.

The piece points to tools and controls such as Mercurial, Buck, Bazel, CODEOWNERS, and CDK as key enablers of large-scale repository management.