Developers inside and outside of Google have told us they are looking for a better way to build apps that delight all their users, without having to build the app twice. To help, we've been working closely with the Flutter team to build an open-source SDK that helps developers write beautiful UIs for all of mobile from a single codebase. Currently in technology preview, Flutter is being used by teams inside of Google.At the previous Dart Developer Summit, the Flutter team showed how they used Dart to render mobile graphics and spinning square. Fast-forward to today: the Flutter team demoed their near-complete implementation of material design and showed real apps built with Flutter running on iOS and Android.Flutter is different than other mobile SDKs. It's built with a best-in-class text rendering engine and the same 2D-to-GL library that Chrome (and others) use, which means its lowest layers are battle-hardened and proven. Flutter does not use the OEM widgets, instead it paints every pixel using its framework and graphics engine. This gives developers tremendous control and expressiveness across all of mobile. However, apps built with Flutter try to feel natural on iOS and Android; Flutter's framework embraces platform differences like scroll physics, iconography, fonts, and gestures.A key benefit of using Flutter is its extremely fast development cycle, thanks to the Dart VM and Flutter's functional-reactive framework. For both iOS and Android, hardware and emulators, developers using Flutter can experience sub-second dev cycles as they add and debug app UIs. The app's state is maintained during the reloads, which means developers can iterate very quickly without restarting their app for every change. "We measure our dev cycles in milliseconds", said Eric Seidel, engineer on Flutter.The new Flutter plugin for IntelliJ was also announced. Building on the existing strong support for Dart on the JetBrains platform, the Flutter plugin helps you run, debug, and hot reload on mobile devices and emulators from within a full IDE.Though much progress has been made, Flutter is still in technology preview. The Flutter and Dart teams are working to build out further features such as accessibility and a plugin architecture.To learn more about Flutter's tech preview, please visit flutter.io and github.com/flutter