What is a header bidding wrapper?

Header bidding became one of the hottest buzzwords in ad tech to overthrow the now obsolete and inefficient waterfall model. With its adoption rate rising every year since 2014, header bidding wrappers offer publishers a way to request real-time bids from multiple demand partners, querying every piece of available inventory using the code placed at the website’s header. In addition, header bidding ensures that your ad inventory is sold for a fair value, increases overall CPM, has excellent flexibility, and comes in many sizes and shapes, with options to fit any ad ops team.

so What is header bidding wrapper?

A header bidding wrapper is a javascript code that stays on the publisher’s webpage, making requests to the demand partners and finding bids for them. It can manage multiple demand partners while defining rules, for instance, the number of bidders participating and how long the auction waits for bids.

A bid wrapper will guarantee that every demand partner has their bid request triggering at the same time. Furthermore, wrappers come with a timeout setting, defining how long the browser should wait before closing an ongoing auction. It’s also capable of dropping partners as necessary during the bidding process. Lastly, it comes with a set of analytics tools, helping identify the most efficient methods, warning if a demand resource isn’t winning impressions to remove those subsequently.

How Does Header Bidding Wrappers work?

Publishers can quickly add or remove partners on-demand with a wrapper instead of managing and adding code for each new demand partner. At its core, it will collect bids, generate bid requests, and then communicate them to the ad server.

Wrappers also aim to enhance user experience, ensuring page loading happens first and ads get served a little later, improving page load times. In addition, wrappers are superior to the previously used waterfall model, where ad inventory was offered to one ad network at a time, causing slow page loading. It’s possible to set up a header bidding without a wrapper, but using one will streamline working with several demand partners and improve communication with the ad servers.

Server Side

Server-side header bidding has advantages such as reduced latency and greater scalability, allowing publishers to add more partners without affecting latency. But this comes at the cost of a lower match rate, resulting in lower bidding prices when compared to client-side header biddings due to diminished ad relevance.

Client Side

With client-side header biddings, all the bidding happens within the browser. As a result, it has advantages:

  • Higher CPM (Cost-per-thousand impressions) rates.
  • Better cookie match rates.
  • Increased transparency.
  • Generally higher fill rates.
  • Better targeted ads.

The client-side also has its flaws. For instance, increased latency forcing auctions to be as fast as the slowest bidder, negatively impacting the user experience and causing fewer impressions to be loaded. Compatibility is often a challenge, too, leading browsers to pool connections or, worse, block them altogether. 

In the end, if the user experience and lower latency are more important than overall higher CPM and transparency, server-side head bidding will be the optimal pick. However, client-side header bidding works better for those looking for higher CPM and transparency. 

Choosing the Right Tool for The Job

Publishers can use several wrapper solutions, namely proprietary, open-source, and managed ones. They’re based either on other proprietary or open-source code. Picking the right tool for the job depends on available internal resources and what you need from features.

Open Source

Prebid.js is one of the most prominent open-source wrappers. This free option provides easy-to-implement code that improves header bidding for video and displays ads on websites and over-the-top (OTT) applications.

It enables customization for each publisher, supporting currency conversion, GDPR, common ID systems, multiple ad servers, and more. Prebid.js is the primary pick for several publishers because it’s free, open-source, and neutrality, unlike many proprietary wrapper solutions.

Prebid.js streamlines the set up of line items in your ad server by dynamically resizing any returned creatives to the appropriate size while also only picking the highest price bid and sending both values to the ad server. 

Proprietary Solutions

Amongst the proprietary wrapper solutions, Index Exchange is one of the most popular, with over 30% popularity in the United States. While the market has criticized many proprietary solutions for using their code to favor certain exchanges over others, Index Exchange came to the market intending to be a neutral party.

By creating the Wrapper Ecosystem, the company increased transparency of their tool to show crucial information like reports on partner performance or the inner works of their wrapper. This streamlined the maintenance, deployment, and bidder certification process.

And while open-source solutions may be cheaper, sometimes proprietary solutions like Index Exchange may come with a set of features that better fits your needs.

Managed Solutions

Managed wrapper solutions offer a fair middle ground for publishers that don’t want to invest heavily in dev resources. They provide much-needed implementation support and ongoing management, reducing overall developer costs for publishers. However, it’s essential to pick a solution with robust audit capabilities, allowing the ad ops team to avoid transparency and bias issues.


Header bidding wrappers are a great way to improve revenue and ensure ad inventory is sold at a fair value. However, to make the most out of it, ad ops teams must invest time, resources and do plenty of testing using multiple demand partners. 

So, if you’re looking to improve the bottom line, enhance user experience, and save on dev costs while generally spending less, then a header bidding managed service will ensure you reach the right users with high-quality ad placements.