Nx
By Nrwl
Nx is a build system and set of developer tools designed for managing monorepos, codebases that hold multiple applications and libraries in a single repository. It provides dependency-graph-aware task running, computation caching, and code…
Definition
Nx is a build system and set of developer tools designed for managing monorepos, codebases that hold multiple applications and libraries in a single repository. It provides dependency-graph-aware task running, computation caching, and code generation so that large codebases with many interrelated projects can build, test, and lint efficiently without re-running unaffected work, which keeps CI times manageable as a repository grows.
Overview
Nx exists because monorepos, once a codebase grows past a handful of projects, run into a scaling problem: running every test and build for every commit becomes prohibitively slow, and it is not always obvious which projects a given change actually affects. Nx addresses this by building an explicit dependency graph of all applications and libraries in the repository, inferred from import statements and project configuration, and using that graph to determine exactly which projects are affected by a change and in what order tasks need to run. Mechanically, Nx wraps existing tools rather than replacing them: it can orchestrate webpack, Vite, Jest, ESLint, and other tools through a plugin system, while adding a task scheduler that runs independent tasks in parallel and a computation cache that stores the output of a task keyed by its inputs. If a task's inputs have not changed, Nx replays the cached result instead of re-executing it, which can turn a full monorepo test run into a near-instant no-op for unaffected projects. Nx also offers a remote caching service, Nx Cloud, so that cache hits can be shared across a whole team and CI, not just a single machine. Nx differs from generic monorepo tools like npm/Yarn/pnpm workspaces, which handle dependency linking between packages but provide no task graph, caching, or affected-detection logic on their own. It also overlaps with Turborepo, a more lightweight build system focused primarily on task caching and parallelization without Nx's code generation and plugin ecosystem. Bazel, Google's build system, solves similar problems at a lower level with a steeper learning curve and stricter build definitions, making it more common in very large polyglot codebases. In practice, Nx is used by organizations running multiple frontend applications, backend services, and shared libraries in one repository, particularly in Angular and React ecosystems where Nx has first-party plugin support for generating and configuring new projects. Teams use its `affected` commands in CI to only test and build what a pull request actually touches, cutting CI time significantly on large repositories. The trade-off is added conceptual overhead: Nx introduces its own configuration format, project graph, and caching semantics on top of whatever underlying tools a team already uses, which is a real learning curve for smaller teams or codebases that do not yet have enough projects to benefit from affected-based execution. Teams with a single application or a handful of packages often find plain workspace tooling sufficient without adopting Nx's additional machinery.
Key Features
- builds a dependency graph across all apps and libraries in a monorepo
- runs only tasks affected by a given code change, skipping the rest
- caches task outputs locally and, via Nx Cloud, across a team
- runs independent tasks in parallel to speed up builds and tests
- provides code generators and plugins for common frameworks
- supports incremental adoption on top of existing npm, Yarn, or pnpm workspaces
- integrates with tools such as webpack, Vite, Jest, and ESLint
- visualizes the project dependency graph for a codebase