The fastest way to find out whether your website is accessible is to run an accessibility scan. Just as a security scan lists vulnerabilities, an accessibility scan automatically detects WCAG violations on your site and gives you a concrete starting point. However, understanding what a scan can do and where its limits lie is critical to interpreting the results correctly.
In this article we cover what an accessibility scan is, which problems it finds, the limits of automated tools and a healthy scan-report-fix-monitor cycle.
What Is an Accessibility Scan?
An accessibility scan is a process that automatically examines the code and structure of a web page against WCAG criteria. Such tools (engines like the widely used axe-core are an example) analyze the page's DOM structure, colors, labels and interactive elements to list potential violations.
A scan runs within seconds and usually maps each finding to the relevant WCAG success criterion. This lets you see which problem violates which rule and how to prioritize it.
What Does a Scan Find?
Automated scans are highly effective for problems that can be reliably detected by machines. Common findings include:
- Color contrast: Insufficient contrast between text and background.
- Alternative text (alt text): Missing descriptive alternative text on images.
- Form labels: Input fields lacking accessible labels.
- Heading hierarchy: Headings (H1, H2, H3) not used logically and in sequence.
- ARIA usage: Incorrect or missing ARIA roles and attributes.
- Link and button names: Links or buttons that lack an accessible name.
- Language declaration: The page's language attribute not being specified.
The Limits of Automated Scanning
Scans are a powerful start but are not sufficient on their own. Automated tools cover the portion of WCAG criteria that can be definitively evaluated by a machine; the rest requires human judgment. For example, a tool can tell whether alternative text *exists* for an image, but it cannot assess whether that text *meaningfully describes* the image.
For this reason, a complete accessibility assessment includes the following in addition to an automated scan:
- Manual review: Expert checking of keyboard navigation, focus order and content logic.
- Assistive technology (AT) testing: Real usage trials with screen readers and other assistive technologies.
- User testing: Observing the experience of real users with disabilities.
The table below summarizes the roles of the two approaches:
| Aspect | Automated Scan | Manual / AT Testing |
|---|---|---|
| Coverage | A portion of the criteria | Criteria needing context and meaning |
| Strong area | Contrast, labels, ARIA | Meaning, flow, real use |
| Role | First scan and continuous monitoring | In-depth validation |
A Healthy Cycle: Scan, Report, Fix, Monitor
Accessibility is not a one-off project but a continuous cycle. The recommended steps:
- Scan: Run your site's key pages through an automated scan.
- Report: Map the findings to WCAG criteria and prioritize them by impact level.
- Fix: Address critical and common issues first (contrast, missing labels, alt text).
- Validate: Confirm the fixes with manual review and screen reader testing.
- Monitor: Re-scan every time the site is updated to prevent regressions.
This cycle turns accessibility from a state that degrades over time into a sustainable practice.
Example Scenario
A service company starts a free accessibility scan for its website. The scan finishes in a few seconds and produces a report with dozens of findings: fields in the contact form are unlabeled, half of the product images lack alternative text, and some links in the main menu have insufficient contrast. The team focuses first on easy and effective fixes, adding form labels and alternative text and adjusting the contrast values. It then performs a manual test with a screen reader to confirm that menu navigation actually works. After the next site update, it repeats the scan to make sure no new problems have been introduced. In this way, a process that begins with a single free scan turns into a lasting monitoring habit.
Frequently Asked Questions
Is an automated scan sufficient on its own?
No. An automated scan quickly finds the portion of violations that machines can detect and is an excellent starting point. However, for criteria that require meaning, flow and real use, manual review and assistive technology testing are still necessary.
How often should I scan?
Best practice is to repeat the scan after every significant site update and at regular intervals following the first scan. This catches early on any regressions introduced by new content or design changes.
How should I prioritize the findings in a scan report?
The general approach is to start with problems that have high user impact and are widespread. Findings such as color contrast, missing form labels and alternative text affect many users and are relatively easy to fix.
Does an accessibility scan also help SEO?
Yes, indirectly. Accessibility improvements such as a meaningful heading hierarchy, descriptive link text and alternative text also help search engines understand the content better.
This content is for general information purposes only and does not constitute legal advice.
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