How to fix Error: View engine 'pug' not found (view engine not installed) in Node.js

Install the missing view engine package locally in your project. For Pug:

npm install pug

For other popular engines:

npm install ejs
npm install hbs
npm install handlebars
npm install nunjucks
npm install mustache

Always use npm install (not -g global flag) to install packages that your application code depends on.

Ensure the engine name in your Express code exactly matches the installed package. For example:

const express = require('express');
const app = express();

// Set the view engine to pug
app.set('view engine', 'pug');

// Set the views directory (where template files are stored)
app.set('views', './views');

app.get('/', (req, res) => {
  // This will look for ./views/index.pug
  res.render('index', { title: 'Home' });
});

Common engine names:
- pug - for the pug package
- ejs - for the ejs package
- hbs - for the hbs (Handlebars) package
- nunjucks - for the nunjucks package

Avoid typos and use lowercase (engine names are case-sensitive).

Open your package.json and verify the view engine is listed in dependencies (not devDependencies):

{
  "dependencies": {
    "express": "^4.18.2",
    "pug": "^3.0.2"
  }
}

If the package is only in devDependencies, move it to dependencies. Then check that node_modules exists and contains the package:

ls node_modules/pug

If node_modules is missing or incomplete, run a clean reinstall:

rm -rf node_modules package-lock.json
npm install

Ensure the directory specified with app.set('views', path) exists and contains your template files:

const path = require('path');
const express = require('express');
const app = express();

// Correct: Use path.join for cross-platform compatibility
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

app.get('/', (req, res) => {
  // Express will look for ./views/index.pug
  res.render('index');
});

Create the views directory if it doesn't exist:

mkdir -p views

Place your template files in this directory with the appropriate extension (e.g., index.pug, profile.pug).

If you're using a less common view engine or a custom implementation, you may need to explicitly register it with Express:

const express = require('express');
const nunjucks = require('nunjucks');
const app = express();

// Register nunjucks as the view engine
nunjucks.configure('views', { autoescape: true });
app.engine('html', nunjucks.render);
app.set('view engine', 'html');

app.get('/', (req, res) => {
  res.render('index');
});

Check the documentation of your specific view engine for registration instructions, especially for less common engines or custom solutions.