# The Browsable API > It is a profoundly erroneous truism... that we should cultivate the habit of thinking of what we are doing. The precise opposite is the case. Civilization advances by extending the number of important operations which we can perform without thinking about them. > > — [Alfred North Whitehead][cite], An Introduction to Mathematics (1911) API may stand for Application *Programming* Interface, but humans have to be able to read the APIs, too; someone has to do the programming. Django REST Framework supports generating human-friendly HTML output for each resource when the `HTML` format is requested. These pages allow for easy browsing of resources, as well as forms for submitting data to the resources using `POST`, `PUT`, and `DELETE`. ## URLs If you include fully-qualified URLs in your resource output, they will be 'urlized' and made clickable for easy browsing by humans. The `rest_framework` package includes a [`reverse`][drfreverse] helper for this purpose. ## Formats By default, the API will return the format specified by the headers, which in the case of the browser is HTML. The format can be specified using `?format=` in the request, so you can look at the raw JSON response in a browser by adding `?format=json` to the URL. There are helpful extensions for viewing JSON in [Firefox][ffjsonview] and [Chrome][chromejsonview]. ## Customizing The browsable API is built with [Twitter's Bootstrap][bootstrap] (v 2.1.1), making it easy to customize the look-and-feel. To customize the default style, create a template called `rest_framework/api.html` that extends from `rest_framework/base.html`. For example: **templates/rest_framework/api.html** {% extends "rest_framework/base.html" %} ... # Override blocks with required customizations ### Overriding the default theme To replace the default theme, add a `bootstrap_theme` block to your `api.html` and insert a `link` to the desired Bootstrap theme css file. This will completely replace the included theme. {% block bootstrap_theme %} {% endblock %} A suitable replacement theme can be generated using Bootstrap's [Customize Tool][bcustomize]. There are also pre-made themes available at [Bootswatch][bswatch]. To use any of the Bootswatch themes, simply download the theme's `bootstrap.min.css` file, add it to your project, and replace the default one as described above. You can also change the navbar variant, which by default is `navbar-inverse`, using the `bootstrap_navbar_variant` block. The empty `{% block bootstrap_navbar_variant %}{% endblock %}` will use the original Bootstrap navbar style. Full example: {% extends "rest_framework/base.html" %} {% block bootstrap_theme %} {% endblock %} {% block bootstrap_navbar_variant %}{% endblock %} For more specific CSS tweaks than simply overriding the default bootstrap theme you can override the `style` block. --- ![Cerulean theme][cerulean] *Screenshot of the bootswatch 'Cerulean' theme* --- ![Slate theme][slate] *Screenshot of the bootswatch 'Slate' theme* --- ### Blocks All of the blocks available in the browsable API base template that can be used in your `api.html`. * `bodyclass` - Class attribute for the `
` tag, empty by default. * `bootstrap_theme` - CSS for the Bootstrap theme. * `bootstrap_navbar_variant` - CSS class for the navbar. * `branding` - Branding section of the navbar, see [Bootstrap components][bcomponentsnav]. * `breadcrumbs` - Links showing resource nesting, allowing the user to go back up the resources. It's recommended to preserve these, but they can be overridden using the breadcrumbs block. * `footer` - Any copyright notices or similar footer materials can go here (by default right-aligned). * `style` - CSS stylesheets for the page. * `title` - Title of the page. * `userlinks` - This is a list of links on the right of the header, by default containing login/logout links. To add links instead of replace, use `{{ block.super }}` to preserve the authentication links. #### Components All of the standard [Bootstrap components][bcomponents] are available. #### Tooltips The browsable API makes use of the Bootstrap tooltips component. Any element with the `js-tooltip` class and a `title` attribute has that title content will display a tooltip on hover events. ### Login Template To add branding and customize the look-and-feel of the login template, create a template called `login.html` and add it to your project, eg: `templates/rest_framework/login.html`. The template should extend from `rest_framework/base_login.html`. You can add your site name or branding by including the branding block: {% block branding %}