The digital ecosystem has forever been heavily reliant on identifiers to help understand the impact of advertising within the likes of search , social & programmatic. The very nature of key subject areas like ad targeting, measurement & remarketing are ultimately centered around cookies within the web world.

As the traditional form of implementing some form of analytics/advertising cookies via pixels starts to evolve, the new “best in class” for advertisers to take comes with the approach of server side tagging. This is a very hot topic but is not exactly new, especially when you consider how channels like affiliates work or even the mobile app world of a postback. But what is indeed changing is how server side tagging will play a big role in the future of digital advertising & spoiler alert, it is not all good!

What is Server Side Tagging?

Server Side Tagging is a concept of utilising your own first party data to send to various marketing tags e.g. a Google Floodlight or Facebook Pixel without installing anything on your website. The traditional way of implementing a pixel is known as Client Side Tagging and often revolves around either an image, iFrame or JavaScript tag being pasted into the code of a website.

The fundamental reason a lot of marketing vendors are moving to this way of tagging is due to how cookies operate within it. Client side tagging is heavily reliance on cookies, predominantly 3rd party cookies which are ultimately being blocked or on the roadmap to be culled by 2023. A lot of client side tagging has therefore evolved towards a 1st party cookie solution but these are also not without limitations, particularly within Apple’s browser Safari. Being heavily reliant on cookies for tagging has been a staple of all digital marketing for a long time on web, but it is clear that the future path should move away from these.

And this is exactly where Server Side tagging comes in to try help with this transition. Whilst there are lots of benefits to this approach, do not be confused by the fact that some of the functions of traditional client side cookie based tagging will no longer work or in some cases even be legal depending on what country you are based on data legislation.

It is also important to denote that the client side tagging still plays a key role in the current state of the ecosystem. Therefore it is not recommended to completely switch to server side tagging at this point in time but merely introduce it to supplement & extend your client side tagging.

How does Server Side Tagging work?

One of the key components of server side tagging is having some form of identifier that can be used to various means. Some key points include:

• Whilst client side tagging revolves around activity within an user’s computer / browser, server side tagging handles all of this on the server which is connected to the user whilst they browse the website.

• Server side tagging best works where users are authenticated & known i.e. at the point of a sign up or purchase. When this action occurs, the server will be able to use the key first party data stored to send back data to the relevant marketing tag in a hashed form.

• The hashing of this data at the critical step ensures that there is no chance of data leaking or security concerns.

• A lot of solutions right now are referencing an external ID or event ID which is key if you have both a server side & client side setup firing the same event, which requires some form of deduping.

Advantages

So what are the benefits to implementing server side tagging? There are quite a few core ones that will not only please the marketing side of brands but also the wider business including teams like information security:

• Cookie Reliance : With an implemented server side approach, there is no requirement to depend on cookies for how users are tracked or measured. This therefore allows opportunities to continue doing key marketing use cases such as remarketing, audience suppression & form of attribution which are legacy dependent on cookies.

• Security : There are added measures in place to deal with data that is going to the likes of Google / Facebook as third parties. Any dodgy form of JavaScript implemented client side on a browser can have the ability to take sensitive data that you don’t want falling into the wrong hands. Whereas with a server side approach, you can limit only critical data to flow back as well as having extra power to control no PII slips through or if it does that it is hashed or encrypted.

• Website Load Times : Often site developers complain of heavy amounts of JavaScript or marketing tags implemented on a website playing a role in slowing down a website’s load speed which in turn may hurt user experience & SEO. Server side tagging allows you to remove all the bloat and have a single call that is hosted on the server, to do the exact same function as legacy client side tags. This means a much more faster, secure way of data flow which in general should help with site speed.

• Data Expansion : By having greater control to send data via the server, this can allow brands to go beyond what is the standard in order to evolve marketing analytics and paid campaigns. For example the use of data points such as profit or margin could be easily implemented in a secure manner via server side, whereas in the traditional client side approach maybe this data is too sensitive to share. This acts as an extension of traditional data points to calculate LTV (Lifetime Value) & run more bespoke activity. Other similar approaches can be seen with offline conversions which often relies on a server side approach to pass the data in.

Disadvantages

As with everything, there are also some points to be aware of that may prove to be a limitation or negative when looking to implement server side tagging:

• Cost : By far the biggest one for most brands will be the fact that server side tagging is generally speaking not free. Whereas historically implementing a client side tag has no cost, advertisers must rely on a server to house data & send it to the various tags. Storing this data at scale can be costly & requires some form of cloud infrastructure if starting for the first time.

• Complexity : As an extension to the first point, it is far more complex to implement server side tagging and generally needs to involve a web developer to do properly. Pretty much most people can learn how to implement a pixel on a website by pasting in some code but unfortunately server side tagging is not as easy to install / debug. Facebook have recently launched their CAPI Gateway product which looks to reduce complexity & cost for example, as is how the likes of Shopify implement it.

• Non-Authenticated Traffic : Server side tagging works best for when a known user exists. For those that are anonymous, this is a grey area that cookies have had an advantage to still have some ability to leverage in targeting / measurement. Therefore it is likely we will see more authentication becoming mandatory on website journeys / funnels in order to improve the accuracy of server side tagging.

• Ethics : For some companies, server side tagging & the technical approach behind it has started a conversation of what it could mean to bypass two critical use cases that are having a significant impact on digital advertising: consent & ad blockers. There are certain measures you could take to use server side tagging to still have the ability to track non-consented users or users that are using an adblocker. But in reality, you are also playing a risk against what is morally / legally acceptable.

Supported Platforms / Vendors

At the time of writing, these are the platforms that support server side tagging:

• Facebook have led the way for a while in the media platforms, with their Conversion API product, to which if you are not using it by now, you are at a big disadvantage for things like campaign delivery & measurement on Facebook. For example the latest version of Facebook’s Conversion Lift product only works if you have CAPI installed which is a reminder to how important it is within their platform.

• Google are not far behind, largely promoting their server side offering through their tag manager GTM, which has now the ability to implement server side tracking for all of the core Google products (Google Analytics, GA4, Google Ads & Google Floodlights).

• Other Tag Managers like Tealium, Adobe & Ensighten have had server side offerings for years but are also having to upgrade to support the media platforms. This is normally an additional price to pay if you have their client side tagging solution.

• The other social platforms are also slowly rolling out Server Side offerings, with TikTok much closer to what Facebook has vs the others. Twitter / Snapchat are next in line followed by Pinterest / Linkedin who are a little further behind.

• One vendor that is seemingly quite far behind the rest is Amazon, who have only in the past 12 months rolled out a stronger version of their client side tag for the DSP but are yet to truly onboard a server side offering. This may be down to the fact the large majority of Amazon spend is driving users back onto Amazon where there is no need for this. But considering that Amazon has its own cloud service AWS, it is likely to be prioritised relatively soon in order to keep advertisers who want to serve ads off Amazon happy.

Final Thoughts

Server side tagging is a buzzword that will continue to be at the top of conversation for brands / advertisers who are trying to futureproof their tracking / measurement on web prior to the demise of third party cookies on Chrome in 2023. It is a matter of if and not when for when you should look to implement this. Keep in mind that there are some limitations as well as higher overheads / knowledge to consider. But it is also clear that with a strong setup, your digital marketing can in fact evolve to another level in face of the challenges within the ecosystem.