pywinauto vs FlaUI for Windows UI automation
pywinauto and FlaUI are both open-source tools for controlling user interfaces in Windows. They should not be selected solely from a list of supported technologies. What matters is what the tool can see in the particular application, which language the team uses and how the test suite will be deployed and maintained.
Why the name of the technology alone is not enough
Two applications built with WPF may be entirely different from an automation perspective. One uses standard controls with stable identifiers; the other uses custom tables and graphical components that do not provide the required information in the Windows UI Automation tree.
If the team chooses a tool without a short technical assessment, problems generally emerge only in more demanding scenarios. The test cannot identify an element unambiguously, relies on row order or has to fall back on images and coordinates. The result is expensive maintenance regardless of the chosen framework.
When pywinauto makes sense
pywinauto is used from Python and offers two main ways to access an application: the classic Win32 interface and Microsoft UI Automation. This is practical for older Win32 programs, simpler WinForms applications and modern interfaces that expose elements through UI Automation.
It is a particularly suitable choice when:
- the team already uses Python for tests, tools or data processing;
- window control needs to be combined with checks of files, a database or an API;
- the application contains older Win32 elements;
- the test code needs to be easy to transfer between Python projects.
The pywinauto project is available under the BSD 3-Clause licence.
When FlaUI makes sense
FlaUI is a .NET library that exposes both variants of Microsoft UI Automation through an interface that is natural for C#. It suits teams that develop in .NET, want to use its type system and need to work with the properties of Windows application elements in greater detail.
It is a particularly suitable choice when:
- the tests will be maintained by a C# or .NET team;
- the application is built with WPF or WinForms and its elements are clearly visible in UI Automation;
- the solution needs direct access to UIA2 or UIA3 capabilities;
- the test infrastructure already uses .NET libraries and tools.
FlaUI is available under the MIT licence. Neither tool, however, is automatically more stable for every application.
How to decide without unnecessary risk
First, we use an inspection tool to check the element tree, names, types and identifiers on one key screen. We then verify a short scenario with both relevant candidates: starting the application, completing a form, saving and checking the result. The pilot must also include one more complex element, such as a table or custom dialog.
We compare implementation time, test readability, diagnostic options and behaviour across repeated runs. For an application built on Electron, we consider Playwright instead of either tool; its Electron support is experimental, however, and requires a separate pilot. We explain this further in How to test an Electron application.
What you gain
The tool will suit both the application and the people who will maintain it. Stable identifiers and shared components limit the number of places that need to be repaired after an interface change. An open-source foundation also keeps the test code under your team’s control without dependence on a single supplier.
Next step
Choose one critical scenario and check whether its elements are visible through Windows UI Automation. The result of this pilot—not the technology name alone—should determine whether you select pywinauto, FlaUI or a combined approach. For WPF and WinForms, the overview of their automation options and limitations will also help.