API Reference vs. Swagger UI

Last updated: September 2026

Swagger UI is one of the most widely used tools for rendering OpenAPI documentation. Its compatibility table goes back to 2011, it is Apache 2.0 licensed, and it is still actively maintained by SmartBear, with 5.33.0 released in September 2026. Scalar's API Reference is a modern alternative that offers a more polished developer experience while remaining fully compatible with your existing OpenAPI documents.

When you migrate to Scalar, you unlock additional tools to enhance your API workflow:

• A modern, open-source API testing client, embedded in your API reference
• Instant search functionality built-in

Why Migrate?

Modern UI/UX

Scalar offers a cleaner, more intuitive interface with a modern design that looks great out of the box. The UI is responsive, has a sidebar and full-text search, and provides better navigation for large APIs. Swagger UI added a dark mode in 5.31.0 (December 2025), so that alone is no longer a reason to switch.

Better Performance

Scalar is built with modern web technologies and tuned for large documents, so the interface stays responsive even with hundreds of endpoints. Try it with your own document; that is the only benchmark that matters.

Interactive API Client

While Swagger UI has "Try it out" functionality, Scalar's built-in API client is more powerful—supporting environment variables, request history, code snippet generation in 25+ languages, and a standalone desktop application (optional).

Extensive Customization

Scalar offers 11 built-in themes and extensive CSS customization options. You can style everything from colors and fonts to sidebar layouts and component spacing.

Feature Comparison

Migrate from Swagger UI to Scalar

Migration is straightforward. In most cases, you can swap out Swagger UI for Scalar in minutes while keeping your existing OpenAPI document unchanged.

Basic HTML Migration

Swagger UI

<!doctype html>
<html>
  <head>
    <title>Swagger UI</title>
    <link rel="stylesheet" href="https://unpkg.com/swagger-ui-dist/swagger-ui.css" />
  </head>
  <body>
    <div id="swagger-ui"></div>
    <script src="https://unpkg.com/swagger-ui-dist/swagger-ui-bundle.js"></script>
    <script>
      SwaggerUIBundle({
        url: '/openapi.json',
        dom_id: '#swagger-ui',
      })
    </script>
  </body>
</html>

API Reference

<!doctype html>
<html>
  <head>
    <title>API Reference</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
  </head>
  <body>
    <div id="app"></div>
    <script src="https://cdn.jsdelivr.net/npm/@scalar/api-reference"></script>
    <script>
      Scalar.createApiReference('#app', {
        url: '/openapi.json',
      })
    </script>
  </body>
</html>

Configuration Mapping

Here is how common Swagger UI options map to Scalar:

Integrations

You can use one of our many integrations for basically any programming language and framework.

Theme and Styling

Using a Classic Layout

If you prefer the traditional Swagger UI layout, Scalar offers a classic layout option, that is not too different:

Scalar.createApiReference('#app', {
  url: '/openapi.json',
  layout: 'classic',
})

Built-in Themes

Scalar includes built-in themes:

• default
• alternate
• moon
• purple
• solarized
• bluePlanet
• saturn
• kepler
• mars
• deepSpace
• laserwave

Scalar.createApiReference('#app', {
  url: '/openapi.json',
  theme: 'moon',
})

Custom Styling

Override CSS variables to match your brand:

<style>
  :root {
    --scalar-font: 'Your Font', sans-serif;
    --scalar-color-accent: #0a85d1;
  }
  .dark-mode {
    --scalar-background-1: #1a1a1a;
    --scalar-color-1: rgba(255, 255, 255, 0.9);
  }
  .light-mode {
    --scalar-background-1: #ffffff;
    --scalar-color-1: #121212;
  }
</style>

Additional Scalar Features

These features have no Swagger UI equivalent:

Frequently asked questions

Related

• Learn: What is an API reference? · OpenAPI vs Swagger
• Docs: Swagger UI alternatives · Scalar vs Swagger UI comparison · API reference configuration
• Product: Scalar API References — the open-source renderer you are migrating to

Swagger UI details on this page come from its GitHub repository, release notes, and configuration docs as checked on September 26, 2026. Swagger UI is actively developed and may have changed since. If you find something wrong or out of date, please open an issue and we will correct it.