What is nx.mdx?

nx.mdx is a plugin for the Nx build system that adds first‑class support for MDX files. MDX is a format that combines Markdown (plain‑text documentation) with JSX (React components). With nx.mdx you can write docs, tutorials, or component demos in a single file and have Nx treat them like any other source code-compiling, linting, testing, and caching them automatically.

Let's break it down

  • Nx: a powerful monorepo tool that lets many projects share code, run tasks in parallel, and cache results.
  • MDX: a file type (.mdx) that lets you write Markdown and embed live React components directly in the text.
  • nx.mdx plugin: glue code that tells Nx how to process .mdx files-how to transform the Markdown, compile the JSX, and include the output in your build pipeline.

Why does it matter?

Because it lets developers keep documentation and interactive examples close to the code they describe. Changes to a component automatically update its demo and docs, reducing drift. Nx’s caching means the heavy MDX compilation only runs when the source actually changes, keeping CI fast. It also brings the same linting, type‑checking, and testing tools you use for code to your docs.

Where is it used?

  • In large monorepos that host UI component libraries, where each component ships with a live MDX story.
  • Documentation sites built with Next.js, Gatsby, or Vite that live inside the same repo as the source code.
  • Internal knowledge bases where engineers want to embed runnable code snippets alongside explanations.
  • Open‑source projects that want a single source of truth for README, guides, and component demos.

Good things about it

  • Seamless integration with existing Nx workflows (affected‑files detection, distributed task execution, caching).
  • Enables “code‑as‑documentation” - live examples stay in sync with the implementation.
  • Works with any React‑based renderer, so you can use it in Next.js, Remix, or plain Vite apps.
  • Centralises tooling: one lint config, one TypeScript setup, one test runner for both code and docs.
  • Improves developer experience: hot‑reloading of MDX pages during development.

Not-so-good things

  • Adds another layer of configuration; teams need to learn both Nx and MDX specifics.
  • Build times can increase if many large MDX files are present and caching is not properly tuned.
  • Debugging MDX compilation errors can be confusing because the error originates from a transformed file.
  • Limited ecosystem compared to pure Markdown or pure React; some plugins or remark/rehype tools may not work out of the box.
  • Requires a React environment; non‑React projects cannot benefit directly from nx.mdx.