Run a free accessibility checker on your website and you get a score and a list of issues in seconds. It feels reassuring, especially when the number is green. But passing an automated scan is not the same as having an accessible website, and the gap between the two is where the real risk lives. If you are weighing an accessibility audit vs scan, here is what each one actually tells you.
What an automated scan can do
Automated tools are useful for a first pass. They crawl many pages quickly and flag issues that can be detected in code: images with no alt text, some color-contrast failures, form fields with no label, missing page titles, and empty links or buttons.
If you are just getting started, a scan gives you a baseline and a quick list of easy fixes. Run it regularly and it will catch regressions, like a new page with a broken heading structure or a product photo uploaded without a description.
What a scan cannot do
The catch is that automated tools can only check what can be measured by code. In practice they catch a limited share of the barriers a real user hits. A scanner cannot tell you:
Those are judgment calls. They require a person who knows the standards and knows how assistive technology behaves.
Scanners also produce false positives and false negatives. They flag things that are fine and miss things that are not. A clean report can create false confidence while real problems go unaddressed. That is the worst outcome: you think you are covered, your users know you are not, and the first time you hear about it is a complaint or a demand letter.
What an IAAP-certified audit adds
The International Association of Accessibility Professionals (IAAP) certifies people, not tools. A certified auditor has demonstrated knowledge of the standards, of how different disabilities affect web use, and of how to test for both. That changes what an audit can tell you. TESSA’s accessibility audits are IAAP-certified, and a certified audit adds four things a scan cannot:
- Human plus automated testing. Automated scans establish a baseline. Then a person works through the site the way real users do: by keyboard alone, with a screen reader, at high zoom, with motion reduced. That combination weeds out false positives and surfaces the barriers scanners miss.
- Findings mapped to the standards. Each issue is tied to specific WCAG 2.1 Level A and AA success criteria and, where it applies, the revised Section 508 standards. You know exactly which requirement is at stake and why.
- Plain-English, prioritized guidance. You get recommendations you can act on, ordered by impact on users, not a raw dump of machine output. A blocked checkout comes before a slightly low-contrast footer link.
- Documentation your team can use. A good audit leaves you with a record of what was tested and how, so you can show your work if asked and keep conformance as you add pages or redesign your website.
Accessibility audit vs scan at a glance
| Question | Automated scan | IAAP-certified audit |
|---|---|---|
| How fast is it? | Seconds to minutes | Days, depending on site size |
| What does it check? | Issues detectable in code | Code plus the real experience with assistive technology |
| False positives? | Common | Reviewed and removed by a person |
| Does it test tasks like checkout? | No | Yes, end to end |
| Is it tied to WCAG criteria? | Partly | Every finding |
| Best use | Baseline and ongoing monitoring | Finding and fixing the barriers that matter |
The two are not rivals. A scan is a smoke alarm. An audit is the inspection.
Why it matters
The barriers that lead to complaints tend to be the kind a scan alone cannot catch: navigation that breaks with a keyboard, forms a screen reader cannot complete, content that makes no sense out of visual order. Fixing those is what actually protects your users and reduces your legal exposure. It also tends to make the site clearer and easier for everyone, including people on a phone, in bright sunlight, or in a hurry.
A scan tells you your site might be okay. An audit tells you where it is not, and shows you how to fix it.
Is a free accessibility scan enough for ADA compliance?
No. The ADA does not name a specific tool or score, and courts and regulators generally look to WCAG as the measure of an accessible site. Many WCAG success criteria can only be evaluated by a person. A scan is a reasonable starting point, but on its own it does not show that real users can complete real tasks on your site.
When should you choose an audit instead of a scan?
Use a scan for ongoing monitoring and for catching simple mistakes as content changes. Choose an audit when the stakes are higher: before a website launch or redesign, if you sell online, if you serve government or education clients, or if you have received a complaint. In the accessibility audit vs scan decision, the question is not which is better but whether you can afford to miss what the scan does not see.
Want to know how your site really performs for every visitor? Book a free strategy session and we will talk through where to start.
