Page Canary is a website quality assurance tool designed to autonomously monitor websites and identify issues before they affect users. It uses a unique approach by utilizing your website like a real user, identifying issues that traditional testing methods may miss.

The primary functionality of Page Canary includes its ability to find and rectify issues with your website, reinforcing site reliability and user trust.

It comes packed with more than 10 custom web page audits, each aiming to identify critical functionality problems on your website. This tool checks all links on your page to ensure they are operational and also identifies issues with your website's SSL certificate, including expiry, authority, and security.

In terms of accessibility, it works to ensure your website is available to everyone. Aside from these audits, Page Canary holds several other audits to meet diverse website goals.

Additionally, two different pricing models are available - yearly and pro, each with its own unique features. Overall, Page Canary serves as an automated quality assurance tester, which can be a potent tool to avoid website downtimes and enhance user experience.