Publisher Integration

Header Bidding for Publishers

Header bidding delivers 20-40% CPM improvements by enabling all demand partners to compete simultaneously for every impression.

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About Header Bidding

Header bidding is the most significant yield optimization technology available to web publishers, delivering consistent 20-40% CPM improvements over waterfall setups by replacing sequential inventory offering with simultaneous competitive auctions.

In the legacy waterfall model, publishers offered inventory to demand partners one at a time in a priority order. The first partner willing to pay the floor price won the impression — regardless of whether a lower-priority partner would have paid significantly more. This structural inefficiency consistently left substantial revenue on the table.

Header bidding solves this by moving the auction outside the ad server. Prebid.js (the dominant open-source header bidding wrapper) runs in the browser before the ad server is called, sending bid requests to all configured SSPs simultaneously within a defined timeout window. The highest bid from any SSP — including Stellor Media — is passed to the ad server as a line item. The ad server then compares this bid against any direct deals and serves the highest-value outcome.

The result is a true unified auction where the most valuable buyer always wins — creating the competitive pressure that drives CPMs to their market maximum for each specific impression.

How Stellor Media Implements Header Bidding

Stellor Media integrates with publisher header bidding stacks as a bidder adapter for Prebid.js. Our adapter competes fairly alongside other SSPs in your header bidding configuration, contributing demand from our 50+ partner network to the competitive auction.

During 48-hour onboarding, Stellor's technical team configures: the Prebid.js adapter with your publisher ID and ad unit settings, Google Ad Manager line items at appropriate price granularity, timeout settings optimized for your traffic profile, and floor price configuration aligned with your inventory's market value.

For publishers implementing Prebid Server (server-side header bidding), Stellor maintains a Prebid Server bidder adapter that operates with lower browser-side latency while maintaining demand competition.

StellorMedia also supports hybrid header bidding configurations: client-side Prebid.js for desktop (lower latency, better cookie coverage) combined with server-side Prebid Server for mobile (lower data usage, better for mobile bandwidth-constrained users).

Key Benefits

20-40% CPM Improvement

True competitive simultaneous auctions consistently deliver 20-40% higher CPMs versus waterfall setups from identical inventory.

All Buyers Compete Equally

Every demand partner — including Stellor's 50+ connections — competes on bid price rather than ad server priority position.

Real-Time Price Discovery

Per-impression auctions discover the true market value of each unique combination of user, context, and placement — not a static rate card price.

Transparency

Prebid.js is open-source. Publishers can inspect exactly how auctions work, which partners bid, and how winning bids are calculated.

Prebid Server Option

Server-side header bidding reduces client-side JavaScript overhead for publishers with complex ad setups or latency-sensitive page experiences.

Configurable Timeout

Timeout settings balance revenue (more bids from slower partners) against page performance (faster auction completion). Stellor helps optimize for your traffic.

Frequently Asked Questions

How much does header bidding increase publisher revenue?

Publishers switching from waterfall-only setups to competitive header bidding typically see 20-40% CPM improvements. Combined with dynamic floor pricing, total revenue increases of 30-50% are common.

Does header bidding slow down my website?

With proper implementation — appropriate timeouts, lazy loading for below-fold units, and async tag loading — header bidding adds minimal perceivable latency. Stellor's team provides Core Web Vitals optimization guidance.

How many SSPs should I include in header bidding?

Most publishers run 5-12 SSP adapters. Adding Stellor Media to an existing setup adds competitive pressure without replacing existing partners, improving total revenue without latency tradeoffs.

What is the difference between client-side and server-side header bidding?

Client-side (Prebid.js) runs in the browser — lower latency but uses browser resources. Server-side (Prebid Server) offloads the auction to a server — reduces browser load but may have lower cookie match rates. Stellor supports both.

Ready to Integrate?

Stellor Media handles all technical setup in 48 hours. Take our publisher quiz to get started.

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