Bootstrap
An open-source CSS framework (originally from Twitter) with ready-made components and a responsive grid system for fast web development.
Bootstrap is the world's most widely used CSS framework and has fundamentally changed how websites are built. Originally created by Twitter developers as an internal tool in 2011, it is now an open-source project with millions of installs. The framework provides a mature grid system, dozens of UI components and a consistent design system that greatly speeds up responsive development. Whether landing page, admin dashboard or corporate site – Bootstrap is a solid foundation.
What is Bootstrap?
Bootstrap is a front-end CSS framework that provides HTML, CSS and JavaScript building blocks for responsive, mobile-first websites. At its core is a flexible 12-column grid with breakpoints for different screen sizes (xs, sm, md, lg, xl, xxl), a large set of utility classes for spacing, color, typography and display, and ready-made components such as buttons, cards, modals, navigation, forms and tables. Bootstrap 5 removed the jQuery dependency, added CSS custom properties and improved RTL support. It can be included via CDN, npm or Sass source and customized via Sass variables.
How does Bootstrap work?
Bootstrap uses a mobile-first approach: styles are defined for small screens first and extended via media queries for larger breakpoints. The 12-column grid uses Flexbox (and optionally Grid). Components like navbars, dropdowns and modals come with JavaScript that can be activated via data attributes (data-bs-toggle, data-bs-target). For custom branding, developers override Sass variables before importing Bootstrap so the whole framework uses their colors and fonts.
Practical Examples
A startup builds its marketing site in days with Bootstrap 5: hero, feature cards, pricing table and contact form – fully responsive with minimal custom CSS.
A company builds an admin dashboard with Bootstrap and the AdminLTE template: sidebar, data tables, charts and forms are ready to use.
An agency uses Bootstrap as the base for a custom design system: Sass variables match the brand; custom components extend the framework.
An e-learning portal uses Bootstrap for an accessible learning platform with accessible modals and consistent focus styles.
A non-profit builds a professional donation campaign site with Bootstrap and a free template – no dedicated front-end developer needed.
Typical Use Cases
Rapid prototyping: Quick functional prototypes and MVPs with ready-made components
Responsive websites: Marketing pages, landing pages and corporate sites that must look good on all devices
Admin dashboards: Backends and admin UIs where functionality matters more than unique design
Design systems: Bootstrap as the base for a company UI kit with custom Sass variables and components
Training: A clear, well-documented framework for learning web development
Advantages and Disadvantages
Advantages
- Very fast development: Pre-built components and utilities can cut development time by up to 50%
- Strong responsive grid: Pages adapt to all screen sizes with a mobile-first approach
- Large community and ecosystem: Thousands of templates, themes and extensions
- Consistent design: All components follow one system and consider accessibility
- Easy to customize: Sass variables allow full branding without forking the framework
Disadvantages
- Recognizable default look: Sites without customization often look generic ('Bootstrap look')
- Heavy for small projects: Full CSS is 150+ KB even if only a few components are used
- Rigid class conventions: Highly custom layouts may require overrides and CSS conflicts
- Less utility-first than Tailwind: Utility-based frameworks offer more flexibility for custom designs
Frequently Asked Questions about Bootstrap
What is the difference between Bootstrap and Tailwind CSS?
Is Bootstrap still relevant?
Can I use Bootstrap with React or Angular?
Related Terms
Want to use Bootstrap in your project?
We are happy to advise you on Bootstrap and find the optimal solution for your requirements. Benefit from our experience across over 200 projects.