Overview

xa11y is a cross-platform accessibility client library. It reads accessibility trees exposed by other applications and lets you interact with UI elements — clicking buttons, reading text, filling fields — through a single, unified API.

xa11y/
├── xa11y-core      # Platform-independent types, traits, selector engine
├── xa11y-macos     # macOS backend (AXUIElement)
├── xa11y-linux     # Linux backend (AT-SPI2 via D-Bus)
├── xa11y-windows   # Windows backend (UI Automation)
├── xa11y           # Umbrella crate — re-exports core, picks the right backend
└── xa11y-python    # Python bindings via PyO3

What It Does

Desktop operating systems expose UI structure through accessibility APIs (originally designed for screen readers). xa11y provides a clean abstraction over these platform-specific APIs:

Platform	Underlying API
macOS	AXUIElement (Core Accessibility)
Windows	UI Automation
Linux	AT-SPI2 via D-Bus

Selectors

xa11y uses a CSS-like selector syntax to query accessibility trees:

button                          # by role
button[name='Submit']           # role + exact attribute match
textfield[name^='Search']       # starts-with
textfield[name*='email']        # contains (case-insensitive)
button[name$='Cancel']          # ends-with
group > button                  # direct child
window button[name='OK']        # descendant
button:nth(2)                   # 2nd match

Supported attributes: name, value, description, role. Supported operators: = (exact), *= (contains), ^= (starts-with), $= (ends-with). Pseudo-selectors: :nth(n) to select the nth match.

Supported Actions

Action	Description
press	Click / activate
focus	Move keyboard focus
blur	Remove keyboard focus
toggle	Toggle a checkbox or switch
expand / collapse	Expand or collapse a disclosure
select	Select an item
set_value	Set a text field’s value
type_text	Type text into an element
set_text_selection	Select a text range by offsets
increment / decrement	Adjust a slider or stepper
scroll	Scroll in a direction
scroll_into_view	Scroll element into the viewport
show_menu	Open a context menu