How I Caught LinkedIn Fingerprinting My Browser

I almost always have the console open. Comes with the job, working on various projects means constantly poking around in devtools chasing one bug or another. So when I had LinkedIn open in a tab and glanced over, I noticed the console going absolutely nuts. Red errors, rapid fire, dozens a second.

Over and over. My first thought was that one of my own extensions was busted. I disabled a few, reloaded, still happening. Turned out it wasn't me at all.

The Mechanism Is Almost Insultingly Simple

LinkedIn runs a script on every page load that checks your browser for installed extensions. Not one or two. Somewhere between 2,900 and over 6,000, depending on who's counting and when.

Here's how it works once you see it. Every Chrome extension has an ID, and some extensions expose files that a website is allowed to request directly, things like an icon or a small bundled asset. LinkedIn just tries to load those known files, one after another, for every extension on its list. If the file loads, you have that extension. If it fails, you don't. Ratio that out across a few thousand extensions and that's your console filling up with invalid requests for everything you don't have installed.

This Isn't a Rumor

Researchers have documented the behavior in detail. A German nonprofit called Fairlinked filed a legal case in Munich over it. And when a reporter asked LinkedIn about it directly, they didn't deny it. They called it an "internal research project," something about A/B testing and keeping the platform safe. Sure.

It's Not Just Competitor Sales Tools

The list of extensions being checked isn't limited to scraping bots and rival sales tools, though LinkedIn reportedly checks for 200+ tools that compete directly with its own sales products. The list also apparently includes extensions tied to religion, political leanings, and accessibility needs for neurodivergent users. None of that is disclosed anywhere in LinkedIn's privacy policy. No consent popup, no toggle, nothing.

I keep coming back to the same comparison. It's like someone going through your pockets while you're standing in their house. You didn't ask for it, you weren't told it was happening, and finding out after the fact doesn't make it better.

On Brand for the Parent Company

Honestly, at this point it's just another thing on the pile. Microsoft owns LinkedIn, and between Copilot getting shoved into every corner of Windows whether you want it or not and updates that break things that were working fine the day before, I'm not exactly shocked something like this was running quietly in the background too.

The Part That Actually Gets Me

It isn't the surveillance. It's the pointlessness of it for someone like me. I barely use LinkedIn, posting there occasionally hoping it sends a little traffic back to my own site. The one use case that would justify being on the platform at all is job hunting, and I've spent real time and real money trying to make that work. Never landed a single job through it. These days the platform is so flooded with bots and automated scanning on both sides, employers scanning you, you scanning listings, that it barely functions as what it's supposed to be for.

A platform that can't reliably do the one thing it's for is quietly fingerprinting everyone who shows up anyway. As if you needed another reason to close the tab.

Refs, If You Want to Go Down the Rabbit Hole

• Why is no one talking about LinkedIn exfiling your Chrome extensions — Medium, the 6,222-extension count
• LinkedIn Is Scanning Your Browser Extensions. Yes, All of Them. — DEV Community, the Fairlinked/BrowserGate legal case in Munich
• LinkedIn Is Reading Your Browser. Chrome Let It In. — Secrets of Privacy, on the 200+ competitor sales tools angle
• The Extensions You Use Are Not a Secret, Especially to LinkedIn — JavaScript in Plain English, the manifest.json breakdown of how it works