Tech

Client- Side Ad Insertion (CSAI) or Server-Side Ad Insertion (SSAI). Which method should I choose for my business?

By the tvads team on 25 September 2024

Client-side ad insertion (CSAI) is a method by which the video player, located within an app or a website, requests an ad from an ad server. When the ad server has received the ad request from the video player, it sends an ad and displays it within the video content.

When it comes to ad delivery in Connected TV (CTV) and Over-The-Top (OTT) environments, there are two ways to insert advertising into content: client-side ad insertion (CSAI) and server-side ad insertion (SSAI).

Both solutions allow Addressable TV. In this article we will explain how both technologies work and how to choose between these methods in our business.

Analysing this method, we will find that is has some pros from business perspective:


Easier set up: as it’s a simpler tech stack, the implementation time is shorter

Less expensive: it’s also a less expensive solution as there are less pieces involved in the tech stack


However, this method also has its dark side

Latency and buffering can affect user experience

It’s easy to ad blockers to block spots through this method.

Tech Stack maintenance involves more work.

SSAI is the preferred method in large parts of the CTV industry. It is a method of delivering video ads by stitching them directly to video content on the server side instead of the client application or video player, as is the case with client-side ad insertion (CSAI).The user experience with SSAI can be compared to traditional TV ad breaks, as there is a smooth transition from video content to the ad break. The viewer is not waiting for the ad to load, and it’s a continuous viewing experience without pauses or interruptions between content and ads. The big difference between the user experience compared to traditional television lies in the advertising side, since SSAI offers the possibility of delivering fully personalized and relevant advertising to each user. This high user experience is the main reason why most of the industry is opting for this type of solution that offers the user a smooth experience between content and advertising. From a technical perspective, delivering content and advertising in the same flow initially posed challenges regarding the targeting of these ads, which are solved by combining two key pieces: manifest manipulator and ad server.

Manifest manipulator: responsible for personalizing the video experience for each viewer, presenting different ads to different viewers.

Ad server (or Ad decision server): essential for determining which ad to deliver, whether it is a direct or programmatic campaign through its connections with the different Supply-Side Platforms (SSPs), depending on the parameters of the call, collecting delivery data and different campaign KPIs.

As a summary, this would be an example of an SSAI architecture:

1.   The user’s player makes a video file request to the Content Delivery Network (CDN). At the same time, it requests the manifest to the Manifest Manipulator service.

2.   A modified Manifest is generated with the information of the file to be played and with all the necessary information to play the ads during ad breaks.

3.   All this information is sent to the packager and packaging and encoding are done if needed.

4.   The CDN will deliver the stream with the requested video and inserted ads to the user.

As previously mentioned, the industry is mainly choosing SSAI solutions. Here are some of the main reasons for this choice:


Better user experience

Easy maintenance: no regular code updates required: SDKs are not needed thanks to code-free integration.

Increases the volume of inventory: as the user doesn’t make calls to the ad server, it’s impossible to use ad blockers


This method has also its dark side:

Longer set up: there are more pieces to integrate in the tech stack in order to having our SSAI solution working properly, so set up times on this method usually are longers.

More expensive: as it’s a more complicated tech stack the cost of this solution is higher than the CSAI one

When it comes to choose between CSAI and SSAI it is important to analyse your specific business case. The industry is increasingly choosing SSAI methods, these are usually more expensive and require a greater set up effort, so depending on the needs of your business it may be a better option to start with a CSAI solution.

Development Event Multimedia
tvads team

At tvads we has a professional team able to advise you on this field and and guide you in any area of your streaming advertising business, advising you or even operating it on your behalf if necessary

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