Is bootstrap free and open source?

Yes. bootstrap is open source, available under the MIT license.

Is bootstrap actively maintained?

bootstrap is actively maintained — the latest commit landed within the last month. Its health score is 100/100.

How popular is bootstrap?

bootstrap has 174.3k GitHub stars and about 6.4M downloads per week.

Does bootstrap have known security vulnerabilities?

9 known security advisories are listed for bootstrap in the OSV database.

What are some alternatives to bootstrap?

Alternatives to bootstrap include Tailwind CSS, Bulma, Foundation, Material UI and Pico CSS.

bootstrap

MDX MIT★ 174,344

100

Health 100/100

Baseline50
Commit recency+25
Popularity+20
Adoption+15
Security-20
Release cadence+5
Open-issue load+5

Bootstrap is a CSS-first front-end framework that bundles a responsive grid, prebuilt UI components, and utility classes, plus a small set of JavaScript widgets (built on Popper), letting developers assemble styled, mobile-friendly interfaces without writing CSS from scratch.

css-framework frontend grid-system popper responsive-design sass ui-kit utility-classes

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Embed badge

[![health](https://opensources.dev/resource/bootstrap/badge.svg)](https://opensources.dev/resource/bootstrap)

MITPermissive — free to use in commercial and proprietary software, with attribution.View license →

Production readiness

4/5

Actively maintainedCommits in the last 6 months
No known vulnerabilities9 known OSV advisories
Clear, usable licenseMIT (permissive)
Proven adoptionWidely used
Has documentationDocumentation indexed

Downloads6.4M /wk

MomentumSteady

Security9 known advisoriesGHSA-3mgp-fx93-9xv5 GHSA-3wqf-4x89-9g79 GHSA-4p24-vmcr-4gqj

Bundle size16 KB gzipped0 dependencies

MaintenanceActively maintainedIs bootstrap still maintained? →

Our analysis

Bootstrap is a mature, framework-agnostic CSS/Sass library that ships a 12-column responsive grid, ready-to-use components (navbars, modals, cards, forms, etc.), a utility-class system, and a handful of vanilla-JS plugins for interactivity.

When to use bootstrap

Reach for Bootstrap when you want to ship a clean, responsive UI quickly without designing a system from scratch, for internal tools, admin dashboards, prototypes, marketing pages, or teams that value a familiar, well-documented convention over bespoke styling. Its server-side framework friendliness (no build step required via CDN) also suits Rails/Django/Laravel apps.

When not to

If you want highly custom, brand-distinct designs, a utility-first workflow with minimal shipped CSS, or deep integration with a component model like React/Vue, a tool like Tailwind CSS or a React-native component library (MUI, Radix) is a better fit. Bootstrap's component-driven defaults can produce 'Bootstrap-looking' sites and its bundled CSS is heavier than purged utility frameworks.

Strengths

Extremely well-documented with a huge ecosystem of themes, templates, and Stack Overflow answers
Works without a build step via CDN, and customizable via Sass variables for those who build
Responsive grid and utilities cover most layout needs out of the box
Vanilla-JS plugins removed the old jQuery dependency in v5; ships ESM builds
Long-term stability and semver discipline make upgrades predictable

Trade-offs

Default styling is recognizable, so sites need extra effort to look distinctive
Full CSS bundle is large compared to utility-first frameworks with purging
Component-centric approach can feel constraining vs. utility-first composition
JS components are framework-agnostic but require wrappers for clean React/Vue integration
Customization beyond Sass variables sometimes means fighting specificity and overrides

Maturity

Very mature and battle-tested since 2011, with 170k+ stars, active maintenance, semantic versioning, MIT license, and corporate backing/sponsors. v5 is the current line; docs are built with Astro. It remains one of the most widely deployed front-end frameworks on the web.

Documentation from bootstrap, shown under MIT with attribution. Source: https://getbootstrap.com

Bootstrap 5

Our default branch is for development of our Bootstrap 5 release. Head to the v4-dev branch to view the readme, documentation, and source code for Bootstrap 4.

Quick start
Status
What’s included
Bugs and feature requests
Documentation
Contributing
Community
Versioning
Creators
Thanks
Copyright and license

Quick start

Several quick start options are available:

Download the latest release
Clone the repo: git clone https://github.com/twbs/bootstrap.git
Install with npm: npm install bootstrap@v5.3.8
Install with yarn: yarn add bootstrap@v5.3.8
Install with Bun: bun add bootstrap@v5.3.8
Install with Composer: composer require twbs/bootstrap:5.3.8
Install with NuGet: CSS: Install-Package bootstrap Sass: Install-Package bootstrap.sass

Read the Getting started page for information on the framework contents, templates, examples, and more.

Status

Open Source Security Foundation Scorecard

What’s included

Within the download you’ll find the following directories and files, logically grouping common assets and providing both compiled and minified variations.

bootstrap/
├── css/
│   ├── bootstrap-grid.css
│   ├── bootstrap-grid.css.map
│   ├── bootstrap-grid.min.css
│   ├── bootstrap-grid.min.css.map
│   ├── bootstrap-grid.rtl.css
│   ├── bootstrap-grid.rtl.css.map
│   ├── bootstrap-grid.rtl.min.css
│   ├── bootstrap-grid.rtl.min.css.map
│   ├── bootstrap-reboot.css
│   ├── bootstrap-reboot.css.map
│   ├── bootstrap-reboot.min.css
│   ├── bootstrap-reboot.min.css.map
│   ├── bootstrap-reboot.rtl.css
│   ├── bootstrap-reboot.rtl.css.map
│   ├── bootstrap-reboot.rtl.min.css
│   ├── bootstrap-reboot.rtl.min.css.map
│   ├── bootstrap-utilities.css
│   ├── bootstrap-utilities.css.map
│   ├── bootstrap-utilities.min.css
│   ├── bootstrap-utilities.min.css.map
│   ├── bootstrap-utilities.rtl.css
│   ├── bootstrap-utilities.rtl.css.map
│   ├── bootstrap-utilities.rtl.min.css
│   ├── bootstrap-utilities.rtl.min.css.map
│   ├── bootstrap.css
│   ├── bootstrap.css.map
│   ├── bootstrap.min.css
│   ├── bootstrap.min.css.map
│   ├── bootstrap.rtl.css
│   ├── bootstrap.rtl.css.map
│   ├── bootstrap.rtl.min.css
│   └── bootstrap.rtl.min.css.map
└── js/
    ├── bootstrap.bundle.js
    ├── bootstrap.bundle.js.map
    ├── bootstrap.bundle.min.js
    ├── bootstrap.bundle.min.js.map
    ├── bootstrap.esm.js
    ├── bootstrap.esm.js.map
    ├── bootstrap.esm.min.js
    ├── bootstrap.esm.min.js.map
    ├── bootstrap.js
    ├── bootstrap.js.map
    ├── bootstrap.min.js
    └── bootstrap.min.js.map

We provide compiled CSS and JS (bootstrap.*), as well as compiled and minified CSS and JS (bootstrap.min.*). Source maps (bootstrap.*.map) are available for use with certain browsers’ developer tools. Bundled JS files (bootstrap.bundle.js and minified bootstrap.bundle.min.js) include Popper.

Bugs and feature requests

Have a bug or a feature request? Please first read the issue guidelines and search for existing and closed issues. If your problem or idea is not addressed yet, please open a new issue.

Documentation

Bootstrap’s documentation, included in this repo in the root directory, is built with Astro and publicly hosted on GitHub Pages at https://getbootstrap.com/. The docs may also be run locally.

Documentation search is powered by Algolia's DocSearch.

Running documentation locally

Run npm install to install the Node.js dependencies, including Astro (the site builder).
Run npm run test (or a specific npm script) to rebuild distributed CSS and JavaScript files, as well as our docs assets.
From the root /bootstrap directory, run npm run docs-serve in the command line.
Open http://localhost:9001 in your browser, and voilà.

Learn more about using Astro by reading its documentation.

Documentation for previous releases

You can find all our previous releases docs on https://getbootstrap.com/docs/versions/.

Previous releases and their documentation are also available for download.

Contributing

Please read through our contributing guidelines. Included are directions for opening issues, coding standards, and notes on development.

Moreover, if your pull request contains JavaScript patches or features, you must include relevant unit tests. All HTML and CSS should conform to the Code Guide, maintained by Mark Otto.

Editor preferences are available in the editor config for easy use in common text editors. Read more and download plugins at https://editorconfig.org/.

Community

Get updates on Bootstrap’s development and chat with the project maintainers and community members.

Follow @getbootstrap on X.
Read and subscribe to The Official Bootstrap Blog.
Ask questions and explore our GitHub Discussions.
Discuss, ask questions, and more on the community Discord or Bootstrap subreddit.
Chat with fellow Bootstrappers in IRC. On the irc.libera.chat server, in the #bootstrap channel.
Implementation help may be found at Stack Overflow (tagged bootstrap-5).
Developers should use the keyword bootstrap on packages which modify or add to the functionality of Bootstrap when distributing through npm or similar delivery mechanisms for maximum discoverability.

Versioning

For transparency into our release cycle and in striving to maintain backward compatibility, Bootstrap is maintained under the Semantic Versioning guidelines. Sometimes we screw up, but we adhere to those rules whenever possible.

See the Releases section of our GitHub project for changelogs for each release version of Bootstrap. Release announcement posts on the official Bootstrap blog contain summaries of the most noteworthy changes made in each release.

Creators

Mark Otto

Jacob Thornton

Thanks

Thanks to BrowserStack for providing the infrastructure that allows us to test in real browsers!

Thanks to Netlify for providing us with Deploy Previews!

Backers

Thank you to all our backers! 🙏 [Become a backer]

Copyright and license

View on GitHub

On this page

Bootstrap 5
Table of contents
Quick start
Status
What’s included
Bugs and feature requests
Documentation
Running documentation locally
Documentation for previous releases
Contributing
Community
Versioning
Creators
Thanks
Sponsors
Backers
Copyright and license