For device-near HMIs in all industries, two worlds are often up for debate: Qt/QML with C++ on the device – or web technologies (browser, Electron, WebViews). Both can work. What is decisive are hardware limits, real-time requirements, team skills and the planned lifespan of the product.
What is really being decided
Not “modern vs. legacy”, but: does the UI run smoothly on limited embedded hardware? How close must the interface be to hardware, fieldbus and control logic? Who maintains the software over 5–10 years? This is exactly where Qt/QML+C++ and web stacks diverge.
Qt/QML with C++: strengths
- Performance on ARM/embedded Linux: GPU-accelerated Qt Quick, a lean runtime compared to full browser stacks.
- C++ as the backbone: Performance-critical logic, driver integration and the domain model stay close to the hardware.
- Clear architecture: QML for the UI, C++ for view models and business logic – maintainable and testable.
- Product lifecycle: Many industrial and device manufacturers rely on Qt as a stable platform in the long term.
Web-based HMIs: strengths and limits
Web UIs can be designed quickly and scaled with frontend teams. On desktop or powerful panels this can be convincing. On resource-constrained targets, browser engines, memory consumption and start-up times quickly become a problem. Electron-like stacks are simply too heavy for many embedded devices.
Integration with real-time data, local services and offline operation is also often more elaborate than with a native Qt application.
Decision matrix (simplified)
- Little RAM/CPU, touch HMI, long product lifetime → Qt/QML with C++
- Powerful panel hardware, purely browser-based operation, web team available → web can fit
- Hybrid → Qt/QML for the device-near HMI, web for remote dashboards and service portals
Architecture tip from practice
Regardless of the UI stack, projects rarely fail because of animations – but because of mixed logic. With Qt/QML, a consistent approach is advisable: QML stays declarative, state and domain rules live in C++. This makes tests, performance tuning and later feature extensions easier.
Conclusion for manufacturers in Germany
Anyone building HMIs for devices and systems in any industry – from industrial and automation technology through mobility and energy to consumer, laboratory and special-purpose devices – should not choose web as the default just because frontend talent is available. Qt/QML with C++ remains strong where determinism, resources and longevity matter. Web remains sensible for complementary cloud and service interfaces – not necessarily as a replacement for device-near operation.
Next step
If you are unsure, a short architecture check is worthwhile: target hardware, UI complexity, offline requirements and team skills. This usually makes it clear whether Qt/QML+C++, web or a hybrid is the right path.