Skeleton
A skeleton (also known as a “skeleton loader” or “skeleton screen”) is a placeholder UI that simulates the layout of a page or component while its actual content is loading. It typically takes the form of grey or neutral blocks, lines, or shapes mimicking the structure (e.g., text lines, image boxes) of the final, fully loaded interface. Skeletons give users a sense of the eventual page layout and reduce perceived loading time by showing a visual scaffold instead of a blank page or spinner.
Usage
Improve User Perception: By providing a skeleton screen rather than a blank space, users feel the app is more responsive, as they see a preview of the layout.
Reduce Frustration: A skeleton helps set visual expectations, so users know the content is on its way.
Content Prioritization: As sections finish loading, the skeleton transitions to real content, guiding attention to progressively loaded items.
Use cases
Displaying grey bars where text or titles will appear
Showing faint boxes where images or thumbnails will load
Replacing full content sections with placeholders to indicate the future layout
Not to be confused with
Spinner / Loading Indicator: A spinner is a small animation indicating background work. A skeleton, however, outlines where content will appear, offering a more comprehensive preview of the layout.
Progress Bar: A progress bar quantitatively shows how much of a task is complete (e.g., 60%). A skeleton qualitatively shows how the interface will be structured, without a direct percentage of completion.
Empty State: An empty state implies no content exists yet, whereas a skeleton indicates that content does exist but is in the process of loading.
Best practices
Resemble Real Layout
Approximate the actual shapes and sizes (e.g., a rectangle for an image placeholder, shorter lines for titles, longer lines for paragraphs).
Avoid overusing generic blocks that don’t align with the final design.
Keep It Subtle
Use neutral or low-contrast shades (often grey or off-white).
Skeletons should not be more visually prominent than the eventual content; they are a transitional state.
Use Smooth Transitions
When content finishes loading, gently fade or morph from the skeleton to the real content.
Jarring transitions can confuse users or appear as a flicker.
Match Loading Durations
Keep the skeleton visible only while data is actually loading; remove it as soon as real content is ready.
Prolonged skeleton displays can be frustrating if the data has already arrived.
Performance Considerations
Rendering too many complex skeletons could be counterproductive, leading to increased resource usage.
Balance between providing helpful placeholders and minimizing performance overhead.
Responsive Design
Skeleton shapes should adapt to various screen sizes or aspect ratios, just like the final content.
Ensure skeleton elements maintain the same relative layout.
Accessibility
Make sure that screen readers and keyboard navigation can bypass skeletons.
Provide appropriate ARIA states if needed, indicating that this is a loading placeholder rather than actual content.
Indicate Actual Loading
If skeleton screens are used alongside real-time data fetching, consider subtle animations or shimmer effects that convey ongoing activity.
Use skeletons for data-heavy sections where load times may be noticeable (e.g., large images, extensive lists, or dynamic dashboards).
Summary
A skeleton provides a visual placeholder layout that shows where content will appear while it’s loading. By approximating the final interface’s structure, skeletons help reduce user frustration, enhance perceived performance, and keep users oriented as data arrives. Thoughtful design—mirroring real layout, using subtle colors, ensuring seamless transitions, and considering accessibility—ensures that skeletons improve the loading experience without distracting from the final content.
