bootstrap/site/content/docs/5.0/utilities/api.md

layout	title	description	group	aliases	toc
docs	Utility API	The utility API is a Sass based tool to generate utility classes.	utilities	/docs/5.0/utilities/	true

The bootstrap utilities are generated with the utility API which can be used to change or extend Bootstrap's utility classes. If you don't have any idea what Sass maps are, you can consult the official docs to get started.

The $utilities map contains all utilities and is later merged with your custom $utilities map if present. The utility map contains a keyed list of utility groups which accept the following options:

• property: Name of the property, this can be a string or an array of strings (needed for eg. horizontal paddings or margins).
• responsive (optional): Boolean indicating if responsive classes need to be generated. false by default.
• rfs (optional): Variable to enable fluid rescaling. Have a look at the [RFS]({{< docsref "/getting-started/rfs" >}}) page to find out how this works. false by default.
• class (optional): Variable to change the class name if you don't want it to be the same as the property. In case you don't provide the class key and property key is an array of strings, the class name will be the first element of the property array.
• values: This can be a list of values or a map if you don't want the class name to be the same as the value. If null is used as map key, it isn't rendered.
• print (optional): Boolean indicating if print classes need to be generated. false by default.

Adding utilities to the utility API

All utility variables are added to the $utilities variable. Custom utility groups can added like this:

$utilities: (
  "opacity": (
    property: opacity,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
 );

Output:

.opacity-0 {
  opacity: 0;
}
.opacity-25 {
  opacity: .25;
}
.opacity-50 {
  opacity: .5;
}
.opacity-75 {
  opacity: .75;
}
.opacity-100 {
  opacity: 1;
}

Changing the class prefix

With the class option, the class prefix can be changed:

$utilities: (
  "opacity": (
    property: opacity,
    class: o,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
 );

Output:

.o-0 {
  opacity: 0;
}
.o-25 {
  opacity: .25;
}
.o-50 {
  opacity: .5;
}
.o-75 {
  opacity: .75;
}
.o-100 {
  opacity: 1;
}

Responsive utilities

With the responsive option, responsive utility classes can be generated:

$utilities: (
  "opacity": (
    property: opacity,
    responsive: true,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
 );

Output:

.opacity-0 {
  opacity: 0;
}
.opacity-25 {
  opacity: .25;
}
.opacity-50 {
  opacity: .5;
}
.opacity-75 {
  opacity: .75;
}
.opacity-100 {
  opacity: 1;
}
@media (min-width: 576px) {
  .opacity-sm-0 {
    opacity: 0;
  }
  .opacity-sm-25 {
    opacity: .25;
  }
  .opacity-sm-50 {
    opacity: .5;
  }
  .opacity-sm-75 {
    opacity: .75;
  }
  .opacity-sm-100 {
    opacity: 1;
  }
}
@media (min-width: 768px) {
  .opacity-md-0 {
    opacity: 0;
  }
  .opacity-md-25 {
    opacity: .25;
  }
  .opacity-md-50 {
    opacity: .5;
  }
  .opacity-md-75 {
    opacity: .75;
  }
  .opacity-md-100 {
    opacity: 1;
  }
}
@media (min-width: 992px) {
  .opacity-lg-0 {
    opacity: 0;
  }
  .opacity-lg-25 {
    opacity: .25;
  }
  .opacity-lg-50 {
    opacity: .5;
  }
  .opacity-lg-75 {
    opacity: .75;
  }
  .opacity-lg-100 {
    opacity: 1;
  }
}
@media (min-width: 1200px) {
  .opacity-xl-0 {
    opacity: 0;
  }
  .opacity-xl-25 {
    opacity: .25;
  }
  .opacity-xl-50 {
    opacity: .5;
  }
  .opacity-xl-75 {
    opacity: .75;
  }
  .opacity-xl-100 {
    opacity: 1;
  }
}

Changing utilities

Overriding excising utilities is possible by using the same key. For example if you want more responsive overflow utility classes you can do this:

$utilities: (
  "overflow": (
    responsive: true,
    property: overflow,
    values: visible hidden scroll auto,
  ),
);

Print utilities

Enabling the print option will also generate utility classes for print.

$utilities: (
  "opacity": (
    property: opacity,
    class: o,
    print: true,
    values: (
      0: 0,
      25: .25,
      50: .5,
      75: .75,
      100: 1,
    )
  )
 );

Output:

.o-0 {
  opacity: 0;
}
.o-25 {
  opacity: .25;
}
.o-50 {
  opacity: .5;
}
.o-75 {
  opacity: .75;
}
.o-100 {
  opacity: 1;
}

@media print {
  .o-print-0 {
    opacity: 0;
  }
  .o-print-25 {
    opacity: .25;
  }
  .o-print-50 {
    opacity: .5;
  }
  .o-print-75 {
    opacity: .75;
  }
  .o-print-100 {
    opacity: 1;
  }
}

Removing utilities

Utilities can also be removed by changing the group key to null:

$utilities: (
  "float": null,
);