HBM and Prebid Server

What Is Prebid Server, and When Do You Need It

Prebid Server (PBS) is an open-source solution — Relevant Digital runs its own Go-based fork — that shifts the work of calling multiple demand partners (SSPs) from the user's browser to a high-performance server. It's the shared engine behind three otherwise-separate integration paths: AMP (which has no client-side JavaScript at all), Mobile App (the stored-request/resolved-request mechanics covered in Mobile App Integration), and optional server-to-server bidding on ordinary web pages.

If you've read either of those sections already, you've been using PBS without a dedicated page for it until now — this section documents the engine itself.

The three call types (web context)

On a standard web page, you can run Prebid one of three ways:

Type	What happens	When to use
Client-Side Only	Traditional browser-based bidding — every bidder called from the page	The default; no server involvement
Server-Side Only	Every configured bidder is called via PBS instead of the browser	Once you're confident in server-side performance
Parallel (Hybrid)	Both run simultaneously, client and server bids compete	Recommended for initial testing — lets you compare safely before committing

Reported benefits — and the honest caveat

Moving bidder calls server-side can mean: more bidders competing without loading down the browser, faster page speed from fewer HTTP requests, fewer client-side timeouts, and access to demand integrations that only exist server-side.

None of this is guaranteed automatically. Actual performance improvement depends on your specific bidder mix, traffic, and page weight — it needs to be verified with A/B testing (the Parallel/Hybrid mode above is exactly how you'd run that test) rather than assumed from the general pitch.