Macrotask vs Microtask in Node.js

16 Nov 2025

A practical guide to event loop ordering, Promise callbacks, and process.nextTick.

Node.js event loop order matters when you debug async behavior.

Simple execution order example

console.log("Start");

setTimeout(() => {
  console.log("Macrotask: setTimeout");
}, 0);

Promise.resolve().then(() => {
  console.log("Microtask: Promise.then");
});

process.nextTick(() => {
  console.log("Microtask: process.nextTick");
});

console.log("End");

Output order:

Start
End
Microtask: process.nextTick
Microtask: Promise.then
Macrotask: setTimeout

process.nextTick runs before normal microtasks in Node.js. Use it carefully.