nodemon

Nodemon is a development utility for Node.js (the server-side JavaScript runtime) that automatically restarts your application whenever you save a file change. It solves a tedious problem every Node.js developer faces: normally, after editing your code, you have to manually stop and restart your server to see the changes. Nodemon watches your files and does that restart for you instantly.

Using it is as simple as swapping the word "node" for "nodemon" when you start your app in the terminal — no changes to your actual code required. From that point on, every time you save a file, nodemon detects the change and relaunches the app automatically, so you can just focus on writing code and see results immediately.

It's a pure development tool — something you use while building and testing locally, not something that runs in production. For vibe coders building Node.js backends with tools like Cursor or Replit, nodemon is one of those utilities that becomes so automatic you forget it's even there. It just removes friction.

Beyond the basics, it can also watch specific folders, ignore certain files (like test files or documentation), and even restart non-Node programs written in Python, Ruby, or other languages. It's one of the most downloaded packages in the entire JavaScript ecosystem, with millions of projects depending on it — a testament to solving one simple problem extremely well.