Zapp! An online Dart & Flutter sandbox for

Zapp! is a free online sandbox environment for building & sharing Dart & Flutter applications, supporting all packages, static analysis , embedding, previewing and much more.

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Built for developers

Zero configuration Dart & Flutter
development at your fingertips

Use any package

All web compatible packages from are supported in Zapp! Simply update your pubspec.yaml and start building.


IntelliSense is built directly into the editor, allowing you to quickly preview documentation, jump to sources, apply quick fixes and more.

Share & Embed

Ready to share your app with the world? Share & embed your project into any website with a lightweight, configurable editor.

Live Previews

Instantly preview your application via a unique URL that can be shared with anyone.

Integrated Logs

Logs from your application are viewable directly in the browser, with full stack trace support.

Analyzer Output

With Dart Analyzer integration, view all of your applications problems in one place.

Test Runner (experimental)

Run your tests in the browser, and view the results directly in the editor.


Using a package which provides assets? No problem. Zapp! brings assets to the browser with zero setup.