Tealium is the more common of the two in our index: it runs on 367 websites against 31 for Lytics, and 4 sites use both. Counts come from real scans, not vendor claims.
Lytics is a customer data platform built for marketing teams.
Tealium provides a sales enterprise tag management system and marketing software.
4 sites run both Lytics and Tealium. That is 13% of the sites using Lytics, 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.