How Screen Readers Work: Developer's Guide

To build accessible websites, you must understand how screen readers work. It's not enough to guess – you need to know how your code is actually interpreted and presented to users.

A screen reader isn't just text-to-speech. It's a complex navigation tool that lets users jump between headings, form fields, landmarks, and links. How you structure your HTML directly affects the user experience.

In this guide, we explain how screen readers interpret web pages, which ones are most common, and provide concrete tips for making your sites compatible.

What is a screen reader?

A screen reader is a program that reads screen content aloud for users, primarily for people with visual impairments. But it's more than just narration – it's a complete interface for navigating and interacting with digital content.

Main features:

Who uses screen readers?

Primarily blind users, but also people with severe visual impairments, certain cognitive disabilities, and people who temporarily can't see the screen.

Popular screen readers

There are several screen readers on the market with different strengths:

NVDA (NonVisual Desktop Access)

JAWS (Job Access With Speech)

VoiceOver

TalkBack

How screen readers interpret pages

Screen readers build an internal representation of the page called the accessibility tree. This differs from the DOM:

Accessibility tree:

Example of how a button is interpreted:

<button>Submit</button>

Screen reader announces: 'Submit, button'

It combines the element's content ('Submit') with its role (button).

What happens with CSS?

Navigation patterns

Users don't read web pages linearly. Screen readers offer shortcuts for efficient navigation:

Common shortcuts (vary by screen reader):

What this means for you:

If your headings are incorrectly structured (H1 → H3 → H2), heading navigation doesn't work. If form fields lack labels, F navigation is meaningless.

List views:

Users can list all headings, links, or landmarks on a page. 'Click here' links become incomprehensible in a list. Headings that don't describe content make the list useless.

Try listing all headings or links on your page in a screen reader. If the list doesn't provide a meaningful overview, you have a problem.

Tips for developers

1. Use semantic HTML

Screen readers understand native HTML elements automatically. A needs no extra ARIA. A

requires role='button', tabindex, and keyboard event handlers.

2. Write meaningful alt text

Think: 'What does this image convey?' not 'What does this image show?' A product image might need alt='Red dress size M, $59.99', not 'Image of dress'.

3. Structure headings correctly

Have one H1 per page. Don't skip levels. Headings are users' navigation – treat them like a table of contents.

4. Label forms properly

Connect to with for/id or nesting. Placeholder is NOT a replacement for label.

5. Test with screen readers

Automated tools catch 30-40% of issues. The rest requires manual testing. Download NVDA or activate VoiceOver and navigate your site blind.

6. Handle dynamic content

When content changes (e.g., error message appears), notify the screen reader with aria-live, aria-atomic, or by moving focus.