Scalar: The Modern Open-Source API Platform for Developers |

# Scalar: The Modern Open-Source API Platform for Developers

If you're tired of clunky API clients and want a beautiful, open-source alternative that puts your API documentation first, Scalar is the tool you've been waiting for. This open-source API platform brings together a modern REST API client, stunning API references, and first-class OpenAPI/Swagger support in one elegant package.

## What is Scalar?

Scalar is an open-source API platform that combines the best features of API clients like Postman with the documentation-first approach of tools like Swagger UI. Built with TypeScript and Vue, it offers a sleek, developer-friendly interface that makes working with APIs a joy rather than a chore.

With nearly 15,000 GitHub stars and active development, Scalar has become the go-to choice for teams who want beautiful API documentation without the enterprise price tag.

## Key Features

🎨 Beautiful API References — Transform OpenAPI specs into stunning, interactive documentation
🌐 Modern REST API Client — Full-featured HTTP client with beautifully crafted interface
📖 First-Class OpenAPI/Swagger Support — Native support for OpenAPI 3.x and Swagger specifications
🔐 Advanced Authentication — Built-in OAuth 2.0, API keys, Bearer tokens support
📱 Responsive Design — Optimized for both desktop and mobile devices
🛠️ Customizable Themes — Match Scalar to your brand with CSS variables

## Real Discussions from GitHub Issues

### Issue #9137: ESM Standalone Bundle Support
6 comments — A highly requested feature to add ESM (ECMAScript Module) standalone bundle alongside the existing UMD builds. This enhancement allows developers to use Scalar in modern build environments more easily.

feat(api-reference): add ESM standalone bundle alongside UMD

### Issue #9135: Mobile Layout Optimization
6 comments — The team is actively working on optimizing the mobile experience, ensuring API references look great on smaller screens.

Claude/optimize mobile layout

### Issue #9133: CSS Variables Helper
6 comments — New helper function added to load CSS variables, making customization even easier for developers integrating Scalar into their own projects.

feat(helpers): add load-css-variables to scalar helpers

### Issue #9134: Request Body Content Types Fix
6 comments — Important bug fix addressing request body content types, OpenAPI extras, mime labels, and handling of "other" content types without automatic Content-Type headers.

fix(api-client): request body content types, openapi extras, mime labels, and 'other' without auto Content-Type

## Summary

Scalar represents a new generation of API tools—ones that prioritize developer experience and beautiful documentation. Whether you're documenting your own APIs, integrating third-party services, or building internal tools, Scalar provides the features you need with the polish you deserve.

The active community and responsive maintainers (as evidenced by the lively GitHub discussions) mean issues get addressed quickly and features are continuously added. With its MIT license and open-source nature, you can self-host Scalar or use their hosted version.

Recommended for: Backend developers, API teams, documentation writers, and anyone who wants beautiful, functional API references without enterprise complexity.

## Project Info