Swiper is the more common of the two in our index: it runs on 8,873 websites against 91 for SweetAlert, and 17 sites use both. Counts come from real scans, not vendor claims.
SweetAlert is a JavaScript library that provides alternative alert and modal dialog boxes for web applications, with customisable features, aiming to improve the user interface of the default browser dialogs.
Swiper is a JavaScript library that creates modern touch sliders with hardware-accelerated transitions.
17 sites run both SweetAlert and Swiper. That is 19% of the sites using SweetAlert, 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.