Exploring Client-Side and Server-Side Implementation of Header Bidding: Pros and Cons

Published June 29, 2023


Header bidding has transformed digital advertising by providing publishers with improved income and inventory control. Publishers have two options for adopting header bidding: client-side or server-side. This article examines the advantages and disadvantages of each technique of implementation. We’ll look at client-side header bidding, which takes place in the user’s browser, and server-side header bidding, which takes place on an external server. Publishers can optimize their header bidding strategies and produce maximum results by understanding the benefits and challenges of client-side and server-side header bidding.

I. Client-Side Implementation of Header Bidding:

In client-side header bidding, the ad auction is run in the user’s browser. This means that the browser has to make multiple requests to different ad exchanges and demand partners, which can slow down page load times.

The process of client-side header bidding works as follows:
  • When a user visits a publisher’s website, the browser sends an ad request to the publisher’s server.
  • The publisher’s server sends the ad request to multiple ad exchanges and demand partners.
  • The ad exchanges and demand partners respond with their bids.
  • The browser then selects the winning bid and displays the ad.
Pros of Client-Side Implementation:

Increased Demand Partners and Competition: Client-side header bidding enables the simultaneous integration of different demand partners, fostering healthy competition and driving greater bid rates. This enhances publishers’ revenue possibilities and improves fill rates.

Faster Response Times:Client-side implementation often results in speedier response times because the auction occurs within the user’s browser. This enhances the overall user experience by lowering latency and assuring more consistent ad delivery.

Access to User-Level Data: Client-side header bidding delivers vital user-level data to publishers, such as cookie information and audience insights. Because of this granular data, publishers can serve more targeted and relevant ads, thus enhancing ad performance and revenue.

Improved Fill Rates: With multiple demand partners participating in the auction, client-side header bidding improves fill rates by ensuring more ad opportunities are monetized.

Real-Time Analytics: Client-side header bidding offers real-time analytics and insights into bidding performance, allowing publishers to make data-driven optimisations for increased revenue.

Cons of Client-Side Implementation:

Latency and Page Load Impact: One disadvantage of client-side header bidding is higher latency, which might affect page load times. Integrating many demand partners can cause the page to load slowly, resulting in a poor user experience and eventual user drop-off.

Limited Scalability:Managing and maintaining client-side header bidding integration can become complex and time-consuming, particularly for high-traffic websites. As the number of demand partners grows, scalability may be limited.

Complex Setup and Maintenance:Integrating and managing various demand partners in a client-side configuration necessitates technical expertise as well as ongoing maintenance, which complicates the implementation process.

Ad Quality and Brand Safety Concerns:Due to the diversity of demand sources, client-side header bidding might increase the likelihood of ad quality difficulties and brand safety concerns. To retain brand integrity, publishers must carefully monitor and verify demand partners.

II. Server-Side Implementation of Header Bidding:

In server-side header bidding, the ad auction is run on a server that is separate from the user’s browser. This means that the server does the heavy lifting, which can improve page load times.

The process of server-side header bidding works as follows:
  • When a user visits a publisher’s website, the browser sends an ad request to the publisher’s server.
  • The publisher’s server sends the ad request to a header bidding solution.
  • The header bidding solution runs the ad auction and returns the winning bid to the publisher’s server.
  • The publisher’s server then sends the winning bid to the browser and displays the ad.
Pros of Server-Side Implementation:

Reduced Latency and Page Load Impact:When compared to client-side implementation, server-side header bidding greatly reduces latency and page load impact. The user experience is improved by offloading the auction to an external server, which results in faster page load times and lower latency.

Enhanced Scalability and Flexibility: Because the auction is handled by an external server, server-side approach provides more scalability. Publishers may effortlessly integrate and manage various demand partners while keeping website performance high. It also allows for the addition or removal of demand partners without affecting the website code.

Enhanced User Privacy: Server-side header bidding minimises the number of JavaScript tags that are executed in the browser, resulting in improved user privacy. This addresses the privacy issues raised by client-side tracking and data leaks.

Increased Revenue Potential:Server-side implementation allows publishers to access a greater range of demand sources, including unique demand partners that are not available in client-side configurations. This increases revenue possibilities and diversifies monetization options.

Simpler Integration and Management: Because publishers only need to connect with a single server-to-server partner, server-side header bidding simplifies the integration procedure. This makes implementation and continuing administration chores easier.

Cons of Server-Side Implementation:

Limited Access to User-Level Data: When compared to client-side implementation, server-side header bidding may restrict access to detailed user-level data. Because the auction is conducted outside, publishers may have less visibility into detailed user data, which may have an impact on targeting possibilities.

Reliance on External Server: The auction is conducted by an external server in a server-side implementation. Downtime or server technical issues might disrupt the header bidding process, affecting revenue and ad delivery..

Limited Control Over Auction Mechanics:In comparison to client-side implementation, server-side header bidding may limit publishers’ control over the auction procedures. For bid selection, publishers must rely on the external server’s algorithm and decision-making process.

Potential Data Loss: Because the auction takes place on a third-party server, publishers may have limited access to precise user-level data, potentially leading in a loss of granular audience insights and targeting capabilities.

Comparison of Client-Side and Server-Side Header Bidding-
Feature Client-Side Header Bidding Server-Side Header Bidding
Implementation complexity Easy Complex
Changes to website required No Yes
Page load times Can slow down page load times Improves page load times
Control over the ad auction Less Control More Control
Transparency Less transparent More transparent
Compatibility with ad exchanges and demand partners More compatible Less compatible

Client-side and server-side header bidding solutions both have significant advantages and challenges. Client-side deployment increases demand partners, enables faster reaction times, and gives access to user-level data. Server-side implementation provides lower latency, more scalability, flexibility, and enhanced user privacy. When deciding between client-side and server-side header bidding, publishers must carefully consider their individual requirements and ambitions. Publishers may make informed decisions to maximize revenue potential and provide a seamless user experience by recognising the advantages and downsides.