The test is simple. Go to your website, unplug or disable your mouse or trackpad, and try to navigate using only your keyboard. Tab moves focus forward through interactive elements. Shift-Tab moves backward. Enter or Space activates buttons and links. Arrow keys navigate within menus, radio buttons, and select dropdowns. If you can complete every meaningful action on your site, including filling out a form, activating all navigation links, and clicking all calls to action, using only these keys, your site is keyboard navigable. If you cannot, the gaps you discover are the issues to fix.
The most common keyboard navigation failure is the missing focus indicator. Every interactive element, when it receives keyboard focus, should display a visible outline or other visual indication showing the user where they are on the page. Many designers remove these focus indicators with CSS because the default browser styling, usually a blue outline, conflicts with their design system. Removing focus indicators makes it impossible for keyboard users to navigate because they cannot see where they are. The fix is to define a custom focus style that is visible and on-brand rather than removing the indicator entirely.
Navigation menus that expand on hover do not work for keyboard users. If your navigation includes dropdown menus that appear when a mouse hovers over a parent item, keyboard users cannot access those submenus without specific keyboard support added to the menu implementation. The fix is to ensure that dropdown menus can be opened with Enter or Space when the parent item is focused, that users can navigate through the submenu items with Tab or arrow keys, and that pressing Escape collapses the submenu and returns focus to the parent.
Forms require careful keyboard handling throughout. Every field should be reachable via Tab in a logical reading order that follows the visual layout of the form. Custom interactive components like date pickers, star rating inputs, range sliders, and multi-select chips need keyboard interaction patterns appropriate to their function. These patterns are documented in the ARIA Authoring Practices Guide, which specifies the expected keyboard behavior for every type of interactive component. If you are using a component that does not follow these patterns, users who navigate by keyboard will not know how to interact with it.
Modal dialogs and overlays require specific keyboard handling that many implementations get wrong. When a modal opens, focus should move into the modal automatically. While the modal is open, Tab and Shift-Tab should cycle through the elements inside the modal without allowing focus to escape to the content behind it. Pressing Escape should close the modal and return focus to the element that triggered it. A modal that allows focus to escape to background content is disorienting for keyboard users and a WCAG failure.
Keyboard navigability is not a specialized accessibility feature for a narrow audience. It is fundamental usability infrastructure that affects power users who prefer keyboard navigation, people with motor impairments who cannot use a mouse, and anyone using a device with a keyboard but no pointing device.