Semantic UI Online Editor - Free Playground

Semantic UI takes a different approach to CSS class naming. Instead of cryptic abbreviations like col-md-4 or uk-card-body, you write classes that read like English: ui three column grid, ui large red button, ui raised card. The idea is that your HTML should describe what the UI is, not what CSS properties it needs.

It sounds like a small thing, but it makes a real difference when scanning markup. You can read a Semantic UI template and understand the layout without checking the docs.

Why try Semantic UI in an online editor?

Semantic UI's class names are intuitive, but there are a lot of them. The framework has an extensive set of components -- buttons, cards, grids, menus, modals, forms, and more -- and each one supports multiple variations through natural-language modifiers.

An online playground is a fast way to:

Test how class modifiers combine (what does ui inverted teal segment actually look like?)
Prototype a page without installing Node.js, Gulp, or any build tools
Share a UI mockup with your team as a live, editable link
Compare Semantic UI's output with Bootstrap or other frameworks

Semantic UI class names in action

Here is an example that shows off the natural-language naming convention:

<!DOCTYPE html>
<html>
<head>
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/semantic-ui/2.5.0/semantic.min.css">
</head>
<body style="padding: 20px;">
  <div class="ui container">
    <h1 class="ui header">Recent Activity</h1>
    <div class="ui three stackable cards">
      <div class="ui card">
        <div class="content">
          <div class="header">Pull Request Merged</div>
          <div class="meta">2 hours ago</div>
          <div class="description">
            Refactored authentication module. Removed 340 lines of dead code.
          </div>
        </div>
        <div class="extra content">
          <span class="right floated"><i class="comment icon"></i>4 comments</span>
          <i class="check circle green icon"></i> Approved
        </div>
      </div>
      <div class="ui card">
        <div class="content">
          <div class="header">Deploy to Production</div>
          <div class="meta">5 hours ago</div>
          <div class="description">
            Version 2.14.0 deployed. All health checks passing.
          </div>
        </div>
        <div class="extra content">
          <span class="right floated"><i class="server icon"></i>3 instances</span>
          <i class="check circle green icon"></i> Live
        </div>
      </div>
      <div class="ui card">
        <div class="content">
          <div class="header">Issue Opened</div>
          <div class="meta">Yesterday</div>
          <div class="description">
            Memory usage spikes during CSV imports over 500MB.
          </div>
        </div>
        <div class="extra content">
          <span class="right floated"><i class="bug icon"></i>Bug</span>
          <i class="exclamation circle orange icon"></i> Open
        </div>
      </div>
    </div>
  </div>
</body>
</html>

Look at the class names: ui three stackable cards, extra content, right floated. You do not need to know the framework to understand what this markup produces. The stackable modifier means the cards will stack vertically on smaller screens. That is the Semantic UI philosophy -- the code documents itself.

The state of Semantic UI

Active development on the original Semantic UI has stalled, but the community fork Fomantic UI continues to maintain and extend it. For new projects, Fomantic UI is generally the better choice since it gets regular updates and bug fixes.

That said, the original Semantic UI still works fine for prototyping, learning, and smaller projects. The class naming system remains one of the most readable in any CSS framework.

Try Semantic UI on OneCompiler

OneCompiler's Semantic UI editor lets you include the CDN, write your natural-language classes, and see the rendered components instantly.

Open the Semantic UI Online Editor on OneCompiler

It is a quick way to test component variations, build a mockup, or just see what ui inverted violet segment looks like without setting up a project.