About Perceivable

Perceivable is an independent project that regularly checks UK public sector websites for accessibility issues and publishes what it finds.

Public sector websites must meet accessibility standards so that everyone can use public services, including disabled people. Our aim is to spot problems early, make progress visible and help the people who run these websites, not to catch anyone out.

We start with council websites. Read our methodology to see exactly what we check and what our results do and don’t mean.

About PerceivableBot

If you’ve found this page from your website’s logs, you’ve seen our crawler. It identifies itself with this user agent:

Mozilla/5.0 (compatible; PerceivableBot/0.1; +https://perceivable.co.uk/about)

• It visits fewer than ten pages on each website per check, one at a time, with a pause between each.
• It only loads pages. It doesn’t submit forms, sign in or click anything.
• It runs from cloud servers, so its IP addresses can change.
• It follows robots.txt, including Crawl-delay. To stop it visiting your site, add this to your robots.txt file:

User-agent: PerceivableBot
Disallow: /

If you block us, your site will be shown as not checked. We would much rather work with you, so please get in touch if our crawler is causing problems.

Verifying our requests

Because our IP addresses change, we identify our crawler cryptographically using Web Bot Auth (HTTP Message Signatures). Our public key is published at /.well-known/http-message-signatures-directory. We are registering PerceivableBot with Cloudflare’s verified bots programme, and will sign every request with this key once registration is complete.

Contact

Email hello@perceivable.co.uk about results, corrections, our crawler or anything else.