Full Answer
Client-side = blockable browser scripts. Server-side = unblockable server code. Different reliability.
Cherry Seed
What's the difference between server-side and client-side tracking?
attribution model
conversion tracking
channel grouping
Quick Answer
Client-side: JavaScript runs in browser (can be blocked by ad blockers). Server-side: code executes on server before page renders (can't be blocked). Server-side captures events regardless of browser extensions, Safari ITP, Firefox ETP.