Qt, Electron or Tauri: how to choose a migration path for your application
When migrating an existing application, the choice between Qt, Electron and Tauri depends mainly on what you need to preserve and which problem the change should solve. Qt is worth investigating if you have existing C++ application logic and extensive integrations with the operating system or devices. Electron and Tauri may be candidates if you want to reuse a web interface. Make the final choice after testing an important product feature with its data and installation process.
A new product can be designed without many of those existing commitments. Migration adds another cost: users still need to open their files, finish work in progress, use integrations and receive fixes. Comparing the technologies alone is therefore not enough to estimate the transition.
First, check whether you need to change technologies
Identify the limitation in the current application. Does it fail to run on a required operating system? Do changes introduce new bugs? Are staff waiting for documents to open, or is the interface difficult to use? Each situation calls for a different scope of work. Replacing the tools used to build the interface will not necessarily fix slow data retrieval from a server.
Compare a full migration with updating libraries, replacing a particular feature or improving the existing code. If the application meets your requirements and the problems affect only a small area, rewriting it may add cost without a proportionate benefit. An unsupported dependency or an inability to serve a required platform may change that calculation, but you need evidence of the specific limitation.
In our work modernising TimeCamp's desktop application, we address critical areas alongside ongoing product development. The scope includes a controlled release process and tests of existing functionality: time tracking, projects and time entries. This approach requires identifying the behaviours that must remain correct as changes are introduced.
What does choosing Qt, Electron or Tauri mean for a migration?
Qt: investigate which logic and integrations you can retain
If your application contains valuable C++ logic, check whether it can be separated from the current interface and reused. Sharing a programming language does not make code automatically compatible. It may depend on the previous interface, libraries or functions specific to one operating system.
Qt provides both Qt Widgets and Qt Quick. Widgets supports traditional, complex desktop interfaces; Quick allows more dynamic interfaces, including touch interfaces. As a buyer, you need to know which approach supports the actual work: forms, keyboard shortcuts, multiple windows or data presentation. Choosing Qt alone does not establish that the application will be faster.
Electron: reuse the web interface and budget for desktop work
Electron combines web technologies with Chromium and Node.js. Chromium displays the interface, while Node.js allows code to run beyond the restrictions of an ordinary website. These components ship with the application, which matters when assessing installers and updates.
An existing web interface may reduce the work needed on screens. You still need to check sign-in, local files, printing, offline use and operating system integration. A team familiar with the web application may not have experience releasing software for customers' computers. Agree who will take responsibility for that work.
Tauri: check dependencies on the user's environment
Tauri combines a web interface with application code written in Rust. It uses the operating system's web rendering component, known as a WebView, rather than bundling Chromium as Electron does. This can reduce the application package size, but package size does not measure the memory required to run the application.
The WebView engine differs across operating systems: Tauri uses WebView2 on Windows and WebKit-based components on macOS and Linux. Test the required functionality in your customers' environments. When moving from Electron, do not assume that modules using Node.js will work unchanged. Replacing them or connecting them to the new application needs its own plan and estimate.
Before comparing proposals, document what is not visible on screen
List file formats and local databases, device integrations, background services, shortcuts, notifications and permissions. For each item, establish who uses it and what happens if it stops working. An export used only occasionally may be essential to month-end closing; click counts alone do not determine its importance.
Include customers' computers and installation policies. You need specific operating systems and versions, the distribution method, and confirmation of whether users can install components and updates. A claim that software “runs on Windows, macOS and Linux” does not confirm that it works on every configuration covered by your agreement.
Library licences need a separate review. Qt offers commercial and open-source options, with terms that also vary between modules. Before accepting an estimate, identify the components and distribution model so you can confirm the obligations and any fees. Avoid reducing the comparison to “Qt costs money; the others are free”. Maintaining dependencies and meeting their licence requirements takes work in every option.
Test the risk that could change your decision
Choose a feature that is difficult to replace, rather than a demonstration sign-in screen. For example, a document application could be tested by opening an old file, editing it, saving it and printing it. This is a hypothetical scenario; the right scope depends on your product.
Compare the same workflow using the same data on representative computers. Measure time until the application is ready for work, responsiveness during the task, memory use and load over a longer session. Distinguish the download size, installed size and resources consumed while running. Results from an empty window cannot support a performance promise for a complex application.
The trial should also show how much existing code can be retained, what needs to change and which uncertainties remain. That evidence helps narrow the estimate. If a proposed approach fails to meet the requirements, ruling it out at this stage is a useful outcome.
Plan the transition for users, data and future releases
Consider a staged migration when the old and new parts can work together through a clearly defined way of exchanging data. That arrangement has costs too: the connection and compatibility between both parts need to be maintained. If features are tightly coupled, separating a stage may be harder than replacing an entire small application. Ask the supplier to explain the boundaries of the first change.
A rollback plan must cover data saved after the update. Reinstalling the old application is not enough if it cannot read the new format. Agree how backups, conversion and completeness checks will work, and how you will handle work users have completed since the switch.
Include installation, upgrading a previous version, interrupted updates and recovery in acceptance testing. Electron's distribution documentation separates packaging, signing, publishing and updating. These are also distinct tasks in a deployment plan. Naming a framework does not settle how the new version will reach users' computers.
Agree what access the application needs to files and operating system functions. Electron's security guidance covers separating web content from privileged operations and updating dependencies. Tauri provides controls for granting and restricting permissions for windows and WebViews. In both cases, configuration and application code need to be checked. The technology's name does not guarantee data protection.
When comparing proposals, include analysis, moving features and data, testing, distribution, the period of maintaining both versions and future updates. If that information is missing, an initial software modernisation assessment can establish what to retain, which change to test first and what evidence should guide the decision on further migration.
