Bootstrap 6 with npm

Set up a Bootstrap 6 project that compiles Sass to CSS using npm command-line tools, with no JavaScript bundler. Bootstrap's pre-built JS bundle is loaded directly via a <script> tag. Requires Node.js and terminal familiarity.

Workflow

• Step 1: Set up npm and install dependencies
• Step 2: Create the project structure
• Step 3: Configure npm scripts and config files
• Step 4: Import Bootstrap's Sass
• Step 5: Verify

Step 1: Set up npm and install dependencies

1. Create the project and initialize npm:

   mkdir my-project && cd my-project
   npm init -y
   

2. Install Bootstrap and its optional peer dependencies (omit @floating-ui/dom if not using menus/popovers/tooltips; omit vanilla-calendar-pro if not using the datepicker):

   npm i --save bootstrap@6.0.0-alpha.1 @floating-ui/dom vanilla-calendar-pro
   

3. Install the tools to compile and post-process CSS:

   npm i --save-dev autoprefixer postcss postcss-cli sass
   

4. Install local dev tooling (watch, run scripts, serve, lint):

   npm i --save-dev nodemon npm-run-all sirv-cli stylelint stylelint-config-twbs-bootstrap
   

Step 2: Create the project structure

mkdir {css,scss}
touch index.html scss/styles.scss postcss.config.js stylelint.config.mjs

Target layout:

my-project/
├── css/
├── scss/
│   └── styles.scss
├── stylelint.config.mjs
├── index.html
├── package-lock.json
├── package.json
└── postcss.config.js

Step 3: Configure npm scripts and config files

1. postcss.config.js — run Autoprefixer after Sass:

   const autoprefixer = require('autoprefixer')
   
   module.exports = {
     plugins: [
       autoprefixer
     ]
   }
   

2. index.html — link the compiled CSS and load Bootstrap's pre-built JS bundle (no bundler here, so use dist):

   <!doctype html>
   <html lang="en">
     <head>
       <meta charset="utf-8">
       <meta name="viewport" content="width=device-width, initial-scale=1">
       <title>Bootstrap w/ npm</title>
       <link rel="stylesheet" href="css/styles.css">
     </head>
     <body>
       <div class="container py-4 px-3 mx-auto">
         <h1>Hello, Bootstrap and npm!</h1>
         <button class="btn-solid theme-primary">Primary button</button>
       </div>
       <script type="module" src="node_modules/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
     </body>
   </html>
   

3. package.json — add scripts. Note --load-path=node_modules so Sass resolves bootstrap:

   {
     "scripts": {
       "css-compile": "sass --load-path=node_modules --style expanded --source-map --embed-sources scss:css",
       "css-prefix": "postcss --config postcss.config.js --replace \"css/*.css\" \"!css/*.min.css\"",
       "build": "npm-run-all --sequential css-compile css-prefix",
       "watch": "nodemon --watch scss/ --ext scss --exec \"npm run build\"",
       "serve": "sirv --port 8080 --dev .",
       "start": "npm-run-all build --parallel watch serve",
       "lint": "stylelint \"scss/**/*.scss\""
     }
   }
   

4. stylelint.config.mjs:

   /** @type {import('stylelint').Config} */
   export default {
     extends: 'stylelint-config-twbs-bootstrap'
   }
   

5. Start the dev server:

   npm start
   

Step 4: Import Bootstrap's Sass

Add to scss/styles.scss using the modern @use rule (never @import):

// Import all of Bootstrap's CSS
@use "bootstrap/scss/bootstrap";

Customize tokens with with () — include only the keys you want to change:

@use "bootstrap/scss/bootstrap" with (
  $root-tokens: (
    --border-radius: .25rem,
    --spacer: 1.5rem,
  )
);

Override CSS custom properties through the token maps ($root-tokens and each component's $*-tokens map), following Customize › Sass. Token names are written unprefixed in Sass (e.g. --border-radius, --spacer); Bootstrap's dist/CDN CSS runs PostCSS to add the --bs- prefix, so compiling the source yourself keeps them unprefixed.

Step 5: Verify

1. Run npm start and open http://localhost:8080 — the .container and .btn-solid.theme-primary button should be styled once the CSS compiles.
2. Confirm css/styles.css is generated and updates when you edit scss/styles.scss (watch is running).
3. Confirm no console errors from the JS bundle.
4. Run npm run lint to check Sass against Bootstrap's stylelint config.
5. Bootstrap 6 requires a browser that supports oklch() and color-mix().

For an optimized build that imports only the parts of Bootstrap you use, see the twbs/examples sass-js project.