UserWay is the more common of the two in our index: it runs on 315 websites against 267 for AccessiBe, and 1 sites use both. Counts come from real scans, not vendor claims.
AccessiBe is an accessibility overlay which claims to provide ADA and WCAG compliance. The system scans and analyzes a website, and applies adjustments which they claim make your website ADA and WCAG 2.1 compliant.
UserWay is a web accessibility overlay for websites that claims to improve compliance with accessibility standards.
1 site runs both AccessiBe and UserWay. That is 0% of the sites using AccessiBe, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.