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Supercharge Your Qt Development with Felgo QML Hot Reload

Stop waiting for Build, Package and Deployment


The only Hot Reload for Qt Projects

Boost Productivity and Efficiency, Focus on Development

Felgo QML Hot Reload revolutionizes the way you build and iterate on your applications. Designed for developers and product teams, Felgo QML Hot Reload empowers you to apply code changes instantly. No need for time-consuming recompilation and deployment. Welcome to the future of Qt development!

Hot Reload applies changes in your source code without losing the state of your application. If you are currently working on a sub-page, you will not have to navigate back to it after every change, you will stay exactly where you are in your application.

Save Development Time, Every Day

Software development requires constant testing on each device and platform, many times per day. Use Felgo’s QML Hot Reload to apply changes instantly to the running program. This saves up to 40 hours of development time per month, per developer.


Lightning-Fast Iteration

See your changes come to life in realtime and iterate on the UI without interruption.

When you are working on a sub-page, you don’t need to navigate back to it after every change and wait for the recompilation of the project. You will stay exactly where you are in your application and see the changes within a second.


Platform Agnostic

Works on all Qt-supported platforms: Embedded, Desktop, Mobile and Web. Streamline the development workflow for your entire team, across all platforms.

You can connect any number of target devices in parallel. This allows you to test code changes on different platforms and devices at the same time.

Benefits and Use Cases

Accelerated Development Cycle

Felgo Hot Reload eliminates repetitive build, deploy and navigation cycles. You can see changes instantly and focus on improving your application code.

Increased Collaboration

Strengthen collaboration within your team. Developers and product owners can test changes and explore solutions together in real-time.

Improved Debugging

Debugging becomes more efficient and effective. You can see instant results and directly address issues. The UI stays functional even if you introduce errors to your code.

Concurrent Testing

Test on multiple platforms and devices in parallel and compare results. This saves time and allows you to spot platform-specific differences with ease.


Edit Properties and Bindings

Change property values or bindings. Updates propagate through the UI to keep the state valid

Change JavaScript Logic

Create or edit functions and signal handlers. Change JavaScript logic in binding expressions.

Modify the QML Tree

Add, remove or change Items in the QML scene. Base type and Component changes affect all existing and future instances.

Error Screen & Rollback

Immediately spot errors on-screen. The application keeps the last valid state. Continue coding without interruption.

Change Singletons

Modify singletons to change the application theme or other global configurations.

Test on multiple Platforms & Devices

Connect multiple devices to see your code changes applied on any platform and device at the same time.

What our Customers Say


"We wanted to make a really good product - no compromises on quality due to time constraints. This is why we went for a supplier like Felgo. It was just a seamless way of working together."

Noir Lumière

"We chose Felgo because of its high level of Qt expertise. Their professional services team helped us to introduce new features and solve problems fast and efficiently."


"I really had a good feeling about the team already just from working with the Felgo SDK. The working relationship was easy, excellent results, great team.

Felgo really stepped up to the plate and honored my faith."

Comparing Felgo QML Hot ReloadUse the Best Tool available!


Get Felgo QML Hot ReloadAvailable for Qt and Felgo Projects

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Standalone for Qt

Felgo QML Hot Reload is a standalone development tool, available as per developer license, no royalty fees.

Contact us for a free evaluation or schedule a demo to experience the future of Qt/QML development.


With the Felgo SDK

QML Hot Reload is included in the cross-platform Felgo SDK if you are developing Felgo apps or games.


  • How does QML Hot Reload save development time?

    Changes to QML and JavaScript code no longer require compilation and deployment. You can run your code instantly on multiple devices, and continue from the same application state where you were before saving your QML file(s). This allows incremental UI building and fast iterations, saving up to 40 hours per developer per month.

  • Do I need to change my project or QML code to use Hot Reload?

    No. One of the key benefits of Felgo QML Hot Reload is that it works with any QML code and project setup, without having to change anything. Gone are the times where you had to mock data to test new UI with data - QML Hot Reload allows you to see the QML UI changes with the actual live data.

  • Are there dependencies in my production code?

    The production code of your project stays unchanged! Hot Reload is a development tool only, and adds no dependency or footprint in your production or release builds.

  • How can I evaluate QML Hot Reload for my Qt Project(s)?

    Contact us to get an evaluation version of QML Hot Reload for your Qt project. You can take your time and thoroughly test the solution, for free.

  • Do I need to pay royalties or per-device fees?

    No. Felgo QML Hot Reload is a standalone tool that does not have any royalties or per-device fees.

  • What are the licensing and pricing options?

    QML Hot Reload is charged on a per-developer basis. It is offered as a floating license. There are discounts for multi-license orders and for multi-year orders. Contact us for a quote.

  • Are QML modules supported?

    Yes. Every QML language feature from Qt 5 and Qt 6 is supported with Felgo QML Hot Reload, including QML modules.

  • Which target platforms does QML Hot Reload work with?

    The solution supports all available Qt target platforms: Embedded, Desktop, Mobile and Web. If your device can run Qt, you can use QML Hot Reload.

  • What is the difference between standalone QML Hot Reload for Qt and the Felgo SDK?

    The Felgo SDK accelerates Qt development even more, with additional components to save time and Felgo Cloud Builds as Qt CI/CD. If you do not need these additions and are just interested in QML Hot Reload, you can use the standalone version.

  • How can I test on multiple devices simultaneously?

    QML Hot Reload supports multiple target devices by default. Any number of devices can connect to the server app running on your development computer. The server watches your project and sends code changes to all devices at the same time.

  • What are the technical requirements for using QML Hot Reload?

    Both the development computer and your target device require networking capabilities. Connecting the devices to the same local network then allows you to run your code remotely.

  • How does QML Hot Reload work from a technical viewpoint?

    By integrating QML Hot Reload, your application becomes capable of applying code changes at runtime. It can then connect to the server app on your development computer, which forwards code changes via the local network.