Nx vs Lerna: Which Monorepo Tool Should You Use for JavaScript/TypeScript?
Nx and Lerna are not direct competitors anymore. Lerna is a fast, modern build system for managing and publishing multiple JavaScript/TypeScript packages from the same repository, and it now uses Nx under the hood for task running and caching. In practice: choose Nx when you want a full monorepo platform (graph, caching, generators, plugins); choose Lerna when your main job is versioning and publishing many packages and you want a lighter, publish-focused workflow. Many teams run both, since Lerna delegates the heavy task-running work to Nx.
What Nx is and what it solves
Nx is a build system and monorepo toolkit. It targets the problems that appear once a repository holds several apps and libraries:
- Task orchestration — it figures out the dependency order between projects and runs only what is affected by a change.
- Computation caching — task results are cached locally and (optionally) remotely, so unchanged work is replayed instead of recomputed.
- Project graph — a model of how projects depend on each other, used to decide what to build, test, and lint.
- Generators and plugins — scaffolding for apps, libraries, and framework-specific setups.
The value shows up as the repo grows. On a two-package repo the overhead is hard to justify; on a repo with dozens of projects and a slow CI pipeline, affected-only runs and caching are the main reason teams adopt it.
How Lerna's role changed
Lerna historically did two things: run tasks across packages and manage versions/publishing. The task-running half is now handled by Nx, which Lerna uses for its build system. That leaves Lerna focused on the part it is still known for:
- Versioning — deciding and bumping versions across packages.
- Publishing — pushing packages to a registry in the right order.
- Changelog and release flow — managing the release metadata around a multi-package repo.
So the comparison is less "Nx or Lerna" and more "which layer do you need." If your pain is slow builds and CI, that is Nx's layer. If your pain is coordinating releases of many packages, that is Lerna's layer.
Key differences at a glance
| Dimension | Nx | Lerna |
|---|---|---|
| Primary focus | Build system, task orchestration, caching | Versioning and publishing packages |
| Task running | Core strength; affected-only, dependency-aware | Delegates to Nx |
| Caching | Local and remote computation caching | Provided through its Nx integration |
| Project graph | Yes, central to how it decides what to run | Not its focus |
| Generators/plugins | Extensive, framework-oriented | Not its focus |
| Best fit | Large repos, heavy CI, mixed app/library code | Repos whose main challenge is releasing many packages |
Which one fits your project
Use Nx when:
- CI is slow and you want affected-only builds plus caching.
- The repo mixes applications and libraries that depend on each other.
- You want generators and plugins to standardize how projects are created.
Use Lerna when:
- You publish many packages and release coordination is the main pain.
- You want a publish-focused tool without adopting a full platform.
- You are already on Lerna and the task-running side is handled.
Use both when you publish multiple packages and need fast, cached, dependency-aware task execution — this is the configuration Lerna itself points toward, since its build system is Nx.
Combining or migrating in an existing repo
The practical path is incremental rather than a rewrite:
- Confirm your current setup — identify how tasks are currently run and how versions are published.
- Adopt Nx for task running — let it own build/test/lint orchestration so affected-only runs and caching apply.
- Keep Lerna for releases — leave versioning and publishing where they are if that flow works.
- Verify — after switching task running, check that the same projects build and test, and that CI time drops on changes that touch few projects.
Common snags: expecting caching to help before task inputs are configured correctly, and assuming a migration requires moving every package at once. It does not — the two tools are designed to sit in the same repository.