When running a nodejs project on my computer, I ran into a similar error to the one below: var express = require('express'); ^ ReferenceError: require is not defined in ES module scope, you can use import instead This file is being treated as an ES module because it has a '.js' file extension and '/home/ismael/Projects/private-website-blocker/package.json' contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.