JUCE is described as 'has hundreds of classes covering a vast range of tasks from high-level user-interface handling right down to low-level collections, networking, strings, etc' and is an app in the Development category. There are more than 10 alternatives to JUCE for a variety of platforms, including Mac, Linux, Windows, Android and iPhone. The best alternative is Qt, which is both free and Open Source. Other great apps like JUCE are Qt Creator (Free, Open Source), GTK+ (Free, Open Source), wxWidgets (Free, Open Source) and Avalonia (Free, Open Source).
Qt is a cross-platform application framework that is widely used for developing application software that can be run on various software and hardware platforms with little or no change in the underlying codebase, while having the power and speed of native applications.
GTK+ is a multi-platform toolkit for creating graphical user interfaces. Offering a complete set of widgets, GTK+ is suitable for projects ranging from small one-off tools to complete application suites.
wxWidgets is a C++ library that lets developers create applications for Windows, OS X, Linux and UNIX on 32-bit and 64-bit architectures as well as several mobile platforms including Windows Mobile, iPhone SDK and embedded GTK+.
Avalonia is a WPF-inspired cross-platform XAML-based UI framework providing a flexible styling system and supporting a wide range of OSs: Windows (.NET Framework, .NET Core), Linux (GTK), MacOS, Android and iOS.
Uno is the platform for building native mobile, desktop and WebAssembly apps with C#, XAML from single codebase. It's a Universal Windows Platform Bridge that allows UWP-based code (C# and XAML) to run on iOS, Android, and WebAssembly.
NoesisGUI is a User Interface middleware for videogames and realtime applications: - Fast hardware-accelerated vector graphics on GPU and multithreading-aware architecture - High efficient lightweight C++ library without external dependencies on third-party software - Write...
MauiKit is a framework based on QQC2 and Kirigami, that helps to create convergent applications that run on GNU Linux and Android, based on the Maui HIG. MauiKit is an open source framework to make the applications look good, made by...
HISE is a cross-platform open source audio application for building virtual instruments. It emphasizes on sampling, but includes some basic synthesis features for making hybrid instruments as well as audio effects.