What Is Server-Side Tagging?

Server-side tagging (SST) runs tags on a server rather than in a user's browser, sending data through a controlled server-side container before it reaches third-party platforms. It improves page performance, gives teams more control over exactly what data leaves the site, and reduces exposure to browser restrictions like Intelligent Tracking Prevention.

In standard, client-side tagging, every tag runs in the visitor’s browser and can send data directly to whatever third party it’s configured for, which is also why PII Leakage through tags like the Meta Pixel is possible in the first place. Server-side tagging inserts a server in between: the browser sends data to a first-party endpoint, and that server decides what gets forwarded and to whom. It doesn’t eliminate the need for testing: a misconfigured server-side container can still forward sensitive fields, just one step removed from the browser.