The scanner
About HandrailAuditBot
You found this page in your server logs. Our scanner visited your website.
How to stop it
Put these two lines in the robots.txt of your website. Then the scanner will visit no page of your website.
User-agent: HandrailAuditBot Disallow: /
This operates when you give the name of the bot alone. It also operates when you give the name together with other bots in the same block.
You can also send an email to edison@handrailaudit.com with your domain. We will add you to our exclusion list and confirm this to you.
What it is
HandrailAuditBot is the website accessibility scanner of Handrail Audit. It loads a small number of public pages in the same way as a usual browser. Then it examines them against the Web Content Accessibility Guidelines. To do this it uses axe-core. Google Lighthouse and most professional accessibility tools use the same open-source engine.
It gives its name in the user-agent:
HandrailAuditBot/1.0 (+https://handrailaudit.com/scanner)
The user-agent starts with a Chrome identifier because the scanner loads pages with a real browser engine. The user-agents of search engine bots do the same, for the same cause.
What it does, and what it does not do
| It does | It does not |
|---|---|
| Get your homepage and a maximum of two other public pages, usually a contact page or an appointment page | Crawl a full website |
| Wait a minimum of 1.2 seconds between websites, and visit each website one time only | Return again and again, or hold a connection open |
| Record technical accessibility findings only | Copy or publish your page content |
| Obey robots.txt on each request that it makes | Get to a page behind a login, make an account, or submit a form |
What it records
For each finding it records three items. The first is a short piece of HTML that identifies the element that fails, and the position of that element. The second is the accessibility rule that the element fails. The third is one screenshot of the element. It collects no data about the persons who visit your website.
How accurate it is
We measured the scanner against a page where every failure was known in advance. These are the results. We publish them because a count that is too high is the one mistake this business cannot make.
- 71 of 73 instances found, and never more than the truth The scanner is built to report fewer barriers than exist, never more. In every test it stayed below the true count.
- 2.7% cost of counting each element one time A broken element in a shared template is counted once, not once for each page. This loses 2.7% of real findings. All of the loss is in the direction of reporting fewer.
- 4.5 s for one website Three page loads and a wait between websites. Your server sees a few seconds of ordinary browser traffic.
- 19 of 50 WCAG Level A and Level AA criteria a scan can examine And for most of those 19 it tests one part of the criterion only. This is why a scan is not an audit.
What the scanner cannot tell you
A frame that loads but cannot be scripted is recorded, and we tell you about it.
A frame whose script does not finish in time, or whose address returns nothing, produces no findings, no warning, and no record. The result looks complete when it is not.
So an empty list of untested frames is not evidence that every frame was tested. A person finds this. A scan does not.
How it reads robots.txt
The scanner obeys rules addressed to HandrailAuditBot by name, and rules for all bots. It obeys Allow and Disallow path rules, and the most specific rule wins. It obeys the star and dollar wildcards. It matches against the path and the query string.
If your server cannot serve robots.txt at all, we read this as “do not scan” and not as permission. We record a website that opts out, and we skip that website in later runs.
Why we scan
Handrail Audit helps small healthcare practices find and correct website barriers. These barriers stop patients with disabilities. The patients cannot book appointments and cannot use the website. The patients include persons who use a screen reader, persons who use a keyboard, and persons with low vision.
The scanner finds accessibility violations that are public and that you can verify. Thus our letters can show you something real that you can check. We do not send a letter that tries to frighten you. An automated scan finds a part of the accessibility barriers only, and we say this in each document we publish.
Questions
Send an email to edison@handrailaudit.com. We answer.