Skeleton loader

v1.0

A skeleton is a graphical placeholder, reserving physical space in the page for content in cases where a service or action may be slow to resolve. A skeleton can be considered as an alternative to the progress spinner in many situations.

Skin
Marko
React

Considerations

Lightweight

Skeleton states are simple tools that portray that content is still being loaded—helping reduce user uncertainty.

Structured

Skeletons provide visual hierarchy and suggest the content they are meant to represent whenever possible.

Quick

Skeletons should only appear for a few seconds when needed and disappear when content populates a page.

Anatomy

Skeletons are built using shapes as the base layer and stacked with a shimmer gradient to create the loading effect on native screens. Please note the shimmer is omitted on larger web screens.

Shape
Shimmer

Cumulative Layout Shift (CLS)

It is the developer's responsibility to ensure the CLS metric of a page is not negatively impacted by the introduction of a skeleton placeholder; a poor CLS score will occur whenever content shifts unexpectedly. Unexpected movement of page content usually happens because resources are loaded asynchronously or DOM elements get dynamically added to the page above existing content. Skeletons can help mask these problems if they reserve the correct amount of physical space, but can compound the problem when they do not. View helpful skeleton examples in the Skin library.

Usage guidance

When to use

Skeleton loaders on initial page render should be used as a last resort and not built as an integral part of the design
If UI elements need to be loaded
If visual layout/format of the content being loaded is mostly known ahead of time to reduce the probability of layout shift
If the majority of the page will be taking time to load

When to consider something else

If the visual layout/format of the content being loaded is unknown
If you need to indicate processing or that a change will occur on the page
If content can be pre-loaded or optimized in another way, don’t default to skeleton loaders because they’re easy to leverage

Properties

Shape

Skeleton loading experiences are built using simple shapes found within our common components.

Radius

The radii across shapes vary depending on the component:

Images are 8 or 16px and follow our image sizing guidance
Text blocks are 4px
Buttons are fully rounded
Forms are 8px
Full-width images bleed on all edges and have no radius

Default color

Skeletons work across both light and dark modes. Learn more about the available Loading color tokens.

On Secondary color

Skeletons also work on our background secondary color.

Generative AI color

Colored gradient skeletons are used when introducing AI features and generated content. Learn more about how we treat generative AI in the Generative AI foundation. These colored gradients are only to be used for generative AI content.

Building skeletons

Skeletons are structural elements that represent the visual hierarchy of a page. They should be used as simplified placeholders for content versus 1:1 replacements to create simple loading experiences.

Introduction

Keep in mind that a full page skeleton may not be required or used on page load. In most cases titles, imagery, and other content is able to be pre-loaded. Skeletons should only be used for content that is not yet ready. Don’t force a skeleton when it isn’t needed or if it will make the loading experience uncomfortable.

Example

To visually portray how skeletons will look on a page, here is an example of an overarching hierarchy of content. Notice the common components in use such as images, text groups, buttons, and forms that build the overall structure. Detailed elements like program badges, smaller lines of text and icons should not be represented by skeletons. To view a variety of skeleton examples on web, visit the Skin library.