The Downsides of Client-Side Tagging

As marketing tech stacks expand and security concerns increase, the old way of adding tags to your website has come into question. 

It used to be completely acceptable to just add another tag to your website when you wanted to try a new type of campaign, collect more data or simply change marketing technology vendors. 

However, that’s no longer the case for many brands, particularly those who are processing sensitive data, in e-commerce where speed and security are primary or those who are under the jurisdiction of multiple complicated privacy regulations. 

But first, let’s define what client-side tagging is and the purpose it has served until now.

What is client-side tagging?

Client-side tagging is a method where JavaScript tags load directly within the browser to collect data from user interactions. These tags are often managed through a central container and then send the collected information to various analytics and marketing platforms.

This is the way that many organizations handle their data collection today. Each tag – whether it’s for a new platform, a new campaign type or another way to collect data –  is added to the website individually. Every tag collects the data it requires and then sends that data to its associated platform.

This format is popular because it’s easy to implement, but it’s by no means the most effective in our modern landscape. 

It presents many challenges, particularly for brands with sophisticated marketing technology stacks, customer data privacy requirements and security considerations. 

In this post, we’ll share the downsides we’ve noticed from working with several clients who are moving away from client-side tagging for a more secure, private and controlled option called server-side tagging.

How does client-side tagging work?

Client-side tagging involves placing small pieces of JavaScript code, commonly called tags, directly onto your website. When a user visits your website, these tags load along with the rest of the page’s content, allowing for immediate data collection. Tags are able to capture actions like pageviews, clicks, form submissions, and other user interactions in real-time. Once collected, the data is sent directly from the user’s browser to your analytics servers, enabling you to track user behavior instantly.

Key Characteristics of Client-Side Tagging

• Data Collection: The tags pull info directly from the user’s browser, capturing crucial actions like page visits and clicks.
• Real-Time Insights: Since data is sent right away, you can adjust and analyze user behavior on the fly, giving you instant feedback.
• Easy to Implement: Client-side tagging is pretty straightforward to set up, especially with tag management systems that simplify the process.
• Browser Dependency: The performance depends on how well the user’s browser functions. Ad blockers and privacy tools can interfere, so some data might not get collected.

Limitations of Client-Side Tagging

While client-side tagging offers convenience and real-time tracking, there are several limitations that should be considered:

Performance Impact

One big downside? Performance. Having lots of tags on your site can seriously slow things down. That means your site might take longer to load, which no one likes. It frustrates visitors, causes them to leave, and ultimately impacts engagement. Even worse, slow load times can hurt your SEO rankings—search engines don’t love slow sites. The more tags running in the background, the heavier the drag on performance, and that can really hurt your site’s ability to keep visitors or convert them into customers.

Data Accuracy

Another challenge is data accuracy. With more privacy-focused tools, like ad blockers, or browser updates that limit how third-party tags work, data collection becomes harder. These tools can block tags or prevent them from working properly, which leads to incomplete or inaccurate data. If your data’s off, it’s tough to make informed decisions about your campaigns. Client-side tagging can struggle to provide consistent, reliable data in a world where privacy tools are becoming the norm.

Privacy and Security Concerns

Client-side tags also raise some pretty serious privacy and security red flags. Since they’re loaded directly onto your site and visible to users, they can create privacy issues, especially with laws like GDPR in play. Worse, client-side tags can bypass user consent management systems. In some cases, tags can still track data even if a user hasn’t fully consented, opening up potential compliance issues. This can leave your brand exposed to security vulnerabilities and privacy breaches—a big risk for any company dealing with sensitive data.

What are the downsides of client-side tagging?

There’s a good chance you’re using client-side tagging on your site now. If so, you may already be aware of some of the downsides that it presents. 

Some of the downsides we’ll go through below have previously been accepted as “just the way it is”, while others have become significant blockers for many organizations.  

Data Privacy

As privacy regulations have increased over the last several years, the burden of protecting data has fallen on organizations. The failure to protect that data comes with significant risk in the form of fines, lost revenue and reputational damage. 

As you add more tags to your website, you’re essentially trusting your customers’ sensitive data to more partners who may or may not take it as seriously as you do. This is particularly true for brands who operate in geographic locations that make them subject to CCPA and GDPR. 

If you’re using advertising platforms like Meta or Google, the tags associated with those platforms may carry with them significant risk. These platforms reserve the right to collect, store and even sell your customers’ data, which may be a bridge too far for many privacy teams. We’ve worked with several large organizations who’ve been faced with the choice to stop spending with those platforms or completely restructure the way they place tags on their website due to data privacy concerns. 

Ad Blockers

The rise of ad blockers means that your ads are reaching fewer of your target customers. A recent study found that just under 40% of worldwide internet users use some kind of ad blocker. These make your campaigns less effective but they also make your data less accurate. 

These blockers work by identifying any tags from an advertising server and then blocking that tag from tracking any data. They rely on client-side tagging to work, which means you can get your campaign accuracy and data back by moving away from adding tags directly to your website, and to a more modern way. 

Site Security

Duke University found that 80% of US companies have been successfully hacked. 

These vary in severity, from the unnoticed hacks to steal passwords and data, to the ones that bring entire e-commerce sites down for hours at a time. The costs of these can be massive, both in terms of decreased revenue and the resources necessary to manage around a hack like this (customer success, development, and more) but also in brand reputation and trust.

As you add more tags to your website it increases the chances of a hack. Even the most highly-vetted partner could turn into a liability in the hands of a hacker. 

Site Stability

Each of the tags that you add to your website requires time to load and gather the data it requires. When you have just one or two it’s a matter of a fraction of a second, but in this age of large tech stacks, many organizations have many tags for different purposes, ranging from small to large. When combined, these can be a significant draw on site load time, frustrating customers and even driving them to your competitors. 

Even worse, these tags can take your entire site down based on an error on their end. We recently helped a large e-commerce organization remove all client-side tags, which became a necessity when their entire site went down for hours due to an error in a tag for an advertising platform. 

Data Accuracy

Many marketers and data analysts know this story. You’re trying to get even a simple number to judge the impact of your campaigns and it feels impossible. Why? Because every single platform, including the ones dedicated to data analysis and attribution, give you a different answer. 

Each of these is tagging and recording the data from your site differently, causing wildly different numbers based. Instead of one simple number, this leads to confusion, inaccurate attribution and the inability to measure your impact. 

Data Control 

You know your data needs better than anyone, so shouldn’t you be in the drivers’ seat controlling your data? 

Adding tags directly to your site means that you’re giving over control – sometimes a little bit, sometimes a lot – to the platforms you’re using. 

For many brands, this is no longer an acceptable option. Due to rising security risk, privacy regulations and the desire for complete data ownership, they’re taking back control of their data by moving away from client-side tagging.

What should organizations do instead of client-side tagging?

Now that we’ve illustrated the main risks with client-side tagging, let’s look at the other option. 

On the other end of the tagging spectrum is server-side tagging, which only requires one tag container with one tag on the website. That tag collects all of the necessary data and sends it to a server where that data is stored, shared and protected according to your specifications. The server contains all of the tags for your various platforms and advertising channels.

This allows for organizations to create a solution that fits their unique needs. They can add layers of security, anonymize data or even add logic into the data. You’re also not as restricted by ad blockers. The enhanced capabilities of server-side tagging mean that you’ll get more accurate data that respects customer privacy, you’ll be more able to use that data in advertising channels and your website will remain secure. 

Server-side tagging was created specifically to mitigate all of the risks and downsides that we mentioned above, which makes it an excellent option as we move into the future where privacy regulations, security risks and increasingly complicated tech stacks are the norm.

Comparing Client-Side Tagging with Server-Side Tagging

Server-side tagging is a modern approach to data management and collection on the web. It’s highly respectful of data privacy and security concerns, offering organizations the ability to collect richer, more complete datasets without the limitations of client-side tracking. Below is a table that breaks down the comparison between client-side and server-side tagging:

How to Implement Server-Side Tagging

With all of the benefits do come some downsides. Server-side tagging is harder and more costly to implement and maintain. If you get it wrong your all-important data could suffer, making it more difficult to draw the right conclusions and make decisions.

That makes the decision for how to implement server-side tagging even more critical. Many other vendors will steer you away from server-side tagging, simply because they’re not familiar with the complexities or they don’t have the right infrastructure in place to make it work effectively. Others will tell you that they’re using a server-side model when in reality their options are a hybrid of both server-side and client-side, still leaving you open to all of the risks and downsides of client-side tagging.

Many customers come to us after having explored the other server-side options out there, including building their own solution. We’re happy to help craft a custom solution that helps you capture all of the benefits of a server-side tagging solution with none of the downsides.

Server-Side Tagging at Metarouter

At MetaRouter, we’re revolutionizing the way enterprise organizations manage customer data. Our platform built for server-side data processing and routing enables us to deliver critical solutions, including unprecedented ID management, significantly faster page load times, and rock-solid consent and compliance tools. Learn more here.