Client-side vs server-side: who runs the auction?

Client-side vs server-side: who runs the auction?

Header bidding means holding a tiny ad auction the moment your page loads. The question is where it runs.

— Client-side: the auction happens inside the visitor's browser. Easy to set up, but each demand partner (a company bidding for your ad slot) slows the page a little.
— Server-side: the auction happens on a remote server. The page stays fast even with many partners, but you see less data and may get slightly lower bids.

Tiny example: 4 partners? Client-side is fine. 15 partners? The browser chokes, so move them server-side.

1. Start client-side.
2. Add server-side once partners pile up.

In plain English: few bidders, run it in the browser; many bidders, run it on a server.