- Qt 6.11
- Qt Qml
- Prototyping, Debugging and Profiling QML Applications
- Qt 6.11.1 Reference Documentation

Making Applications Scriptable with JavaScript ◦ Prototyping with the QML Runtime Tool

# Prototyping, Debugging and Profiling QML Applications

Qt provides a comprehensive set of tools for prototyping, debugging, and profiling QML applications throughout the development lifecycle.

## Prototyping with the QML Runtime Tool

The qml command-line tool allows you to quickly run and test QML files without writing a full C++ application. This is ideal for rapid prototyping, experimenting with QML features, and testing individual components in isolation.

### QML Preview

QML Preview enables live reloading of QML files while your application is running, allowing you to see changes immediately without restarting the application. This significantly speeds up the development and iteration cycle for user interface development.

## Debugging QML Applications

The QML Debugger provides comprehensive support for QML applications, including breakpoints, expression evaluation, and inspection of QML object properties and bindings. The QML debugger integrates with Qt Creator and can be used to diagnose runtime issues and understand application behavior.

## Performance Analysis

The QML Profiler helps identify performance bottlenecks in QML applications by tracking rendering time, JavaScript execution, signal emissions, and memory allocations. It provides detailed timeline visualizations showing where your application spends time during execution.

See also Tooling and Qt Quick.