Glossary

Monorepo

A monorepo is a single Git repository for multiple projects or packages. All code (frontend, backend, shared libs, mobile apps) lives together. The opposite is a polyrepo (a separate repository per service).

Advantages

Changes to shared code are immediately visible in all projects — no "which library version" problem
Atomic commits: an API change and the corresponding refactor of all consumers — in one PR
Unified CI/CD, linting, tests — less configuration duplication

Disadvantages

Slower CI without caching tools (need to run only changed parts)
More complex access control across different projects

Tools

Nx (JavaScript/TypeScript), Turborepo (JS), Bazel (Google, multi-language). Large monorepos: Google, Meta, Microsoft keep all their code in a single repository.