Why the keyboard test matters
A significant share of your shoppers navigate without a mouse: people with motor impairments, people with repetitive strain injuries, power users who prefer keys, and anyone on a device where the mouse is impractical. For them, the keyboard is not an alternative input. It is the input. If your checkout cannot be completed by keyboard alone, it cannot be completed by them at all.
The keyboard test is also the cheapest accessibility audit that exists. It requires no tools, no expertise, and about fifteen minutes. It surfaces the most common checkout barriers faster than any automated scan, because automated scans check code while the keyboard test checks the actual experience.
Setting up the walkthrough
Put a product in the cart, unplug the mouse or push it aside, and start from the cart page. Use Tab to move forward through interactive elements and Shift+Tab to move backward. Enter activates links and buttons. Space toggles checkboxes and selects radio options. Arrow keys move within radio groups and dropdowns. Escape should close any modal or dropdown. These are the only keys you need.
As you go, watch for three things on every step: Can you reach it? Can you tell where you are? Can you operate it? Reachability is about tab order. Orientation is about the visible focus indicator. Operability is about whether the control does what it claims when activated by keyboard. A checkout that passes all three at every step is rare, which is why the test is useful.
The failures you will find
The most common failure is the invisible focus indicator. The browser's default focus outline has been removed by the theme's CSS for aesthetic reasons, and nothing replaced it. Keyboard users tab through the checkout effectively blind, guessing which element is active. The fix is a visible focus style, and it is a ten-minute CSS change that resolves the single most reported keyboard barrier.
The second most common failure is the keyboard trap: a modal, date picker, or custom dropdown that you can tab into but not out of. On checkout this often appears in shipping method selectors or gift options built as custom widgets. If you cannot Escape or Tab out of it, shoppers using keyboards are stuck, and stuck at checkout means lost.
The third is illogical tab order, usually from elements positioned with CSS in an order that does not match the DOM. The visual layout says name, then address, then city. The tab order says city, then name, then a checkbox from the footer. Positive tabindex values are the usual culprit. The DOM order should match the visual order, always.
Shopify-specific checkpoints
Shopify's checkout is largely consistent, which means the failures cluster in the parts merchants control: the cart page, custom checkout extensions, upsell widgets, and the thank-you page customizations. Test the discount code field, which is often a custom implementation with a non-standard apply control. Test the shipping method radios, which must be arrow-key navigable as a group. Test any address autocomplete, which needs to expose its suggestions to keyboard users and not trap focus in the suggestion list.
Payment method selection deserves special attention. Wallet buttons and installment options render as iframes or custom controls with varying keyboard support. If a payment option cannot be selected and completed by keyboard, that payment method is unavailable to keyboard users, which is both a conversion problem and a compliance problem.
Turning the walkthrough into a habit
Run the keyboard walkthrough after every theme change, app install, or checkout customization, not once a year. It takes fifteen minutes and catches the regressions that automated scans miss, because most keyboard barriers are introduced by new custom widgets, not by decay in old ones. Assign it to whoever does pre-launch QA. The mouse is optional. For some of your customers, the keyboard is not.