Monorepos with Git

A monorepo stores multiple projects or services in one Git repository. Companies like Google, Meta, Twitter, and Airbnb use monorepos. Git provides sparse checkout and submodules to manage complexity at scale.

01.Monorepo vs Polyrepo

Polyrepo: each project in its own repository. Pros: independent versioning, clear ownership, small focused repos. Cons: dependency management across repos is painful, cross-project refactors require multiple PRs, inconsistent tooling. Monorepo: all projects in one repo. Pros: atomic cross-project changes in one commit, shared tooling and CI, easier code reuse and refactoring. Cons: large repo size, more complex CI, requires tooling like Nx or Turborepo.

Distributed Architecture

💻

Your Local

push / pull

☁️

GitHub (Remote)

push / pull

💻

Teammate's Local

02.Git Tools for Large Monorepos

Sparse checkout: clone the whole repo but only check out the subset of directories you need — dramatically reduces disk usage and clone time. Partial clone (--filter=blob:none): clone without file contents initially, download files on demand. Git LFS (Large File Storage): store large binary files like images and videos outside the main Git object store. Submodules: embed one repository inside another at a specific commit.

my-project/

📁my-project/

📁.git/← Git database

📄config

📄HEAD

📁objects/

📁refs/

📄README.md

📁src/

Commands

commands — click to reveal output

git clone --filter=blob:none --sparse https://github.com/org/monorepo.git

Sparse partial clone — no file contents downloaded initially

git sparse-checkout set apps/frontend packages/ui

Check out only the dirs you need

git sparse-checkout add packages/shared-lib

Add another directory to your sparse checkout

git submodule add https://github.com/org/shared-lib libs/shared

Embed a shared library as a submodule

git submodule update --init --recursive

Initialize and download all submodule content

git clone --recurse-submodules https://github.com/org/repo.git

Clone with all submodules downloaded automatically

git log --all -- apps/frontend/ --oneline

View commit history scoped to one app directory only

KNOWLEDGE CHECK

What is a key advantage of a monorepo over a polyrepo setup?

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