How to Integrate Google Ad Manager with Prebid: Essential Setup for Publishers

For publishers looking to unlock more programmatic revenue, integrating Prebid with Google Ad Manager (GAM) is a crucial step. But the process—especially the creation of line items and targeting keys—can be intimidating and error-prone, particularly if you’re scaling up header bidding or running multiple bidders.

Getting the details right in GAM isn’t just an operational task. Mistakes can leave revenue on the table or introduce troubleshooting nightmares. This guide distills the most important Prebid–GAM integration concepts, focusing on real-world steps and best practices for publishers and ad ops professionals.

Understanding the Publisher Ad Server Hierarchy and Prerequisites

Before configuring Prebid with Google Ad Manager, it’s essential to understand the hierarchy that underpins GAM. Orders live under advertisers, and line items live under orders—this structure dictates how you’ll organize header bidding integrations. Deciding early whether you’ll send all bidder responses (‘Send All Bids’) or just the highest (‘Send Top Price’) impacts how many advertisers, orders, and line items you’ll need to configure.

Setting Up Advertisers, Orders, and Templates

For most Prebid configurations, you’ll either create a single ‘Prebid’ advertiser or separate advertisers per bidder, depending on your reporting and tracking needs. Orders are then created beneath these advertisers. If native demand is in play, set up your native creative templates in GAM before moving forward. Next, proactively define your inventory key-value pairs in GAM to match those your Prebid implementation will be sending—think keys like ‘hb_pb’ for price bucket and ‘hb_size’ for ad size. Take care here: GAM will truncate keys longer than 20 characters, so you must align naming between your ad server and bid setup to avoid mismatches.

Building Prebid-Compatible Line Items in GAM

Line items are the critical link between Prebid’s bid data and GAM’s ad serving logic. Each price point and each bidder typically requires a separate line item, and this is where scale and complexity can quickly take over. The number of line items multiplies based on your price granularity and media types (e.g., display, native, video). Automation tools like Prebid Line Item Manager are recommended at scale, but understanding the manual process is key for troubleshooting and for smaller publishers.

Configuring Essential Line Item Settings

Every line item should be tailored clearly: set the correct ad type (display, video, native), name items consistently (‘Prebid – format – bidder – price’), and use ‘Price Priority’ as the item type. For line items representing long-form video (OTT), remember to specify key differentiators like competitive exclusion labels and video duration where needed.

Granular Targeting with Key-Values

Targeting price buckets is central to header bidding. For ‘Send All Bids’, target with keys like ‘hb_pb_BIDDERCODE’ per each bidder and price, whereas ‘Send Top Price’ uses the generic ‘hb_pb’ key. For formats, ‘hb_format’ (or ‘hb_format_BIDDERCODE’ in Send All Bids) keeps display, video, and native demand streams cleanly separated. If you’re running Prebid Mobile, setting the correct inventoryType—especially for video—is crucial to avoid missed demand.

Managing Creatives and Scaling Up Line Item Structures

After line items are in place, creatives must be associated for every ad size you intend to serve. Because a single creative can only show once per line item per page, duplicating creatives to cover multiple sizes or slots is often necessary. This process becomes mechanical but vital to correct ad delivery.

Creative Duplication and Assignment

For each size listed in your line item, create or duplicate a creative asset so that every slot is covered. This prevents serving issues where GAM can’t fill size-specific demand. Attach these creatives directly to line items, double-checking that the creative matches both the designated size and the required targeting. For advanced configurations, creative-level targeting is possible, such as supporting multiple video cache locations or differentiating between ad formats within a single line item.

Duplicating and Managing Large Volumes of Line Items

Scaling up requires methodical copying. Once you’ve built one bidder’s set of price point line items and attached the necessary creatives, duplicate these line items for each price bucket needed. Change key values and names as you go to ensure alignment between Prebid’s key-value targeting and GAM’s expectations. For multi-bidder setups, repeat the process for each bidder—a tedious but essential task unless automated.

Common Pitfalls and Optimization Tips for Publishers

Missteps in Prebid-GAM integration can lead to major lost revenue or broken ad delivery. Many publishers underestimate the importance of matching key names and values or overlook GAM’s character limits, leading to missed targeting. Others make line item naming too generic, complicating troubleshooting and reporting. Another frequent oversight is failing to use creative duplication, resulting in limited creative rotation and overexposed ad units. Finally, without automation, setups with higher price granularity become nearly unmanageable for larger publishers.

Real-World Example: A Multi-Bidder, Multi-Format Site

Consider a publisher supporting display, native, and video demand with three bidders and medium price granularity. This could quickly require over 1,000 line items, each with several creatives attached. In such a scenario, manual setup is infeasible; relying on automation is the only scalable path. But having worked through the manual steps at least once enables more precise diagnosis when automation scripts inevitably need troubleshooting.

What this means for publishers

Getting Prebid and GAM working together isn’t just about technical configuration—it has direct revenue and control implications. A carefully mapped key-value and line item structure provides the transparency needed for bid reclamation, troubleshooting, and reporting granularity. However, poor initial setup can snowball into operational headaches and missed monetization.

Practical takeaway

Take the time to plan your Prebid–GAM integration up front: decide on your approach (Send All Bids vs. Top Price), map out your advertiser and order structure, and document your key-value setup. Always verify that the keys you use match between Prebid config and GAM, keeping within GAM’s naming restrictions.

Use automation for scale, but walk through the manual line item and creative creation process at least once for a deeper operational understanding. Diligence here pays off with cleaner reporting, simpler troubleshooting, and stronger yield over time.

Finally, review your setup periodically. As your demand stack, formats, or price granularity change, be prepared to refactor your line item and targeting structures—staying hands-on with these details helps future-proof your revenue operations.