Why is pnpm most often used in monorepos?
pnpm is most often used in monorepos because its architecture is ideally suited to managing many related packages inside a single repository.
Main reasons
1. Space savings from a shared cache
A monorepo often has dozens or hundreds of packages. npm and Yarn would store the same dependencies in every package. pnpm keeps one copy in .pnpm-store and creates hard links, saving gigabytes of disk space.
2. Fast dependency installation
pnpm installs dependencies in parallel and does not duplicate them, so in a monorepo pnpm install runs much faster than npm/Yarn.
3. A strict node_modules structure
pnpm clearly isolates each package's dependencies, which prevents "hidden" dependencies, a common problem in monorepos where a package accidentally works only because a dependency got pulled in from a neighboring package.
4. Linking packages locally without publishing
Through workspaces, one package can depend on another without an npm registry at all. pnpm does this:
- instantly
- deterministically
- without extra copies
5. Built-in monorepo support
Workspaces in pnpm are part of the architecture, not an add-on. npm and Yarn historically arrived at this later and less efficiently.
Summary
In monorepos, pnpm wins thanks to:
| Advantage | Why it matters |
|---|---|
| Cache instead of copies | less space |
| Fast installation | saves the team's time |
| Dependency isolation | fewer bugs |
| Linking packages locally | convenience in development |
| Native workspaces | simple setup |
Conclusion: pnpm scales perfectly in monorepos, which is why it is most often chosen for exactly that architecture.
Short Answer
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