What Is Bootstrap?

By Indeed Editorial Team

Updated 22 September 2022 | Published 6 June 2021

Updated 22 September 2022

Published 6 June 2021

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Bootstrap is a framework used for creating front-end setups for responsive websites. It is a collection of reusable HTML, CSS and JavaScript code that facilitates a faster workflow. If you are interested in pursuing a career in web development, in-depth knowledge of this framework can prove highly beneficial. In this article, we discuss what is Bootstrap framework, its basic features, advantages and limitations.

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What Is Bootstrap?

What is Bootstrap, can be ex is an open-source toolkit for front-end developers to create responsive, cross-platform webpages quickly and efficiently. This framework is built on the Leaner Style Sheets (LESS) and features an extensive collection of commonly used cascading style sheets (CSS) elements and JavaScript plugins.

The main characteristics of Bootstrap are its reusability and reliability. As a web developer, you can simply insert these pre-written code snippets for creating different styles of the same element. Furthermore, you do not require to troubleshoot errors because all Bootstrap code is tested on multiple platforms with regular sanity checks. But, you need experience working on HTML, CSS and JavaScript to utilise all of Bootstrap's functionality.

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Using Bootstrap In Your Projects

To start using Bootstrap, you are required to select and download a suitable version and include it in your project. It is available as a set of pre-compiled CSS bundles and JavaScript plugins or as a source code package with documentation. For standard web development cases, you can just download a pre-compiled version, add it to your project with a content delivery network (CDN) such as jsDelivr and start using it.

But, if you require to customise the Bootstrap framework, you are required to integrate the source code in your project's pipeline, which requires an additional step. You need a Sass compiler for the Sass CSS extension language included with Bootstrap. You also need Autoprefixer, which applies vendor prefixes to CSS properties automatically at build time. Fortunately, both are included in Bootstrap's build process. To simplify their installation, you can use a package manager such as npm, yarn, Composer or NuGet.

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Basics Of Bootstrap

To start working with Bootstrap efficiently, you are required to know its file structure, layout, content, forms and components at the very least. We have included a brief overview of these features below:

File structure

The standard installation package has a specific folder structure. In version 5.0, the top folder is named 'bootstrap' with two extra folders under it. The CSS folder contains all the style sheet files, and the js folder contains JavaScript files. Both folders contain minified versions of those files and their source maps to use with browser development tools. In some packages, you may also find an additional 'img' folder that contains Glyphicons in .png format.


Bootstrap is built around a flexible grid system that utilises four essential elements to create a flexible layout. They are:


The container class encapsulates and provides structure to the content within. You can centre the content, modify justification to the left or right and adjust the padding from the container edges. Bootstrap even allows you to implement nested containers to create a hierarchy.


Breakpoints are the primary building blocks that allow creating responsive, mobile-first layouts. These are fixed-width elements in the screen-size enumerator (enum) with pre-defined values for standard screen resolutions. For example, the size of 'md' breakpoint is 768 pixels for standard screens with 1366x768 resolution. For HD resolutions such as 1920x1200, you can select 'xl' enum, set at 1200 pixels.


Bootstrap has a limit of 12 columns per row for its grid. The alignment options include start (top left), centre (middle of the container) and end (bottom right). You can use a combination of these alignments to create complex, hierarchical layouts of your tables. If you use more than 12 columns in a row, Bootstrap automatically wraps them around in the second line.


Gutters act similar to how page and printing layouts work in word processing applications. They provide both horizontal and vertical padding to your columns and rows, respectively. You can also modify the width of all gutters at once or set different values for each. Still, you require to adjust the container sizes to prevent overflow of content with extra width.

Bootstrap contains an additional set of utilities that help you adjust most options for your components such as margins, padding or visibility without writing too much code. But, you require to specify the z-index value to each component's property to create overlays.

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Content in Bootstrap is available in four types:


Bootstrap typography has standard settings in the normalize.css file, which allows you to specify the font styles and sizes for headings, body text, hyperlinks and lists. Bootstrap defaults to a browser's native font size for more accessibility, which is usually 16 pixels. As an added feature in version 5, the font sizes scale across multiple devices, so you do not require to specify them for every viewport resolution.


To make the images responsive, Bootstrap uses .img-fluid while keeping the width at 100% and making the height variable. These values ensure that the images scale up or down according to the size of their parent container.


The table tag is optional to use in Bootstrap to ensure maximum compatibility with third-party widgets. You can set different accents for default Bootstrap tables, such as striped or hoverable rows and active tables. You can also make them responsive, but they scroll horizontally instead of scaling their width.


Use figures when you require to display some content with additional text, such as an image with a caption.


As a web developer, you may require to create forms on a website, such as a contact form, login or subscription pages and discussion boards. In such cases, you can use the form feature of Bootstrap with pre-defined selection boxes, text areas, checkboxes, radio buttons and sliders. You can extend the functionality of text boxes with input groups that add one or more form elements on either side. Additional features include autoscaling floating labels inside text boxes and validation properties to form inputs.


Bootstrap components are extra features that provide interactivity to your web pages. For example, the accordion allows you to build collapsible content. Carousels help you create a slideshow of containers that can have text, images or streamed videos with support for navigation controls. You can find a complete list of supported components in Bootstrap's documentation.

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Advantages Of Bootstrap

Most front-end developers prefer Bootstrap to build mobile-friendly websites because of the following advantages:

Responsive system

The primary advantage of Bootstrap is its focus on responsiveness. Its grid system provides pre-defined sizes for different viewport resolutions across multiple devices such as laptops, monitors, tablets and smartphones. So, you can start working on your layouts and include content without having to create a new grid or worrying about resizing the elements. Similarly, the .img-responsive class allows you to insert images and modify their shapes without switching between design and code.

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Since Bootstrap contains an extensively tested library of pre-defined classes with elegant styles, you can add features to your website without coding each one separately. The standardisation of these features ensures that they work and look as intended on all devices and viewports. Bootstrap also contains JavaScript plugins that give you the freedom to include and experiment with interactivity in your webpages. For example, you can use the scrollspy plugin to continuously update your navigation bar as the user scrolls a page.

Extensive documentation

The official Bootstrap website has extensive documentation about downloading, installing and using it in your projects. All the included features have straightforward explanations with examples of implementing their code. You can quickly search for a particular component, check how to use it, code it directly in your project and fine-tune its properties. Even beginners and junior web developers can understand it and start working in a business-as-usual (BAU) environment.


Since Bootstrap is available as open-source software, you can download the complete source with its build tools to modify the core functionality. This customisation allows many developers to create custom themes and templates available on online Bootstrap marketplaces.

Disadvantages Of Bootstrap

Even though Bootstrap is a popular web development framework, it has some limitations in its use, such as:

Large file sizes

Bootstrap CSS and JavaScript files may range from a few tens to hundreds of kilobytes. These sizes do not cause problems on most websites. But, devices on slower networks require to download them first if they are not cached, slowing down initial page views. Furthermore, busy websites can use up their bandwidth quickly if they host their files locally instead of using a CDN.

Frequent framework changes

Each major release of a new version changes the way Bootstrap works. For example, version 4 included many incompatible changes from version 3. Similarly, version 5 has dropped jQuery entirely and stopped supporting some older browsers. Such updates cause costly rewrites of many websites.

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Limited use-case scenarios

Starting with a template and customising its design is a good feature for most websites. But any limitations within that template also apply to all websites using it. For example, some websites may need more columns than Bootstrap's 12 column limit. So using a Bootstrap template would not work unless you modify its grid system to bypass this limit.

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