Programmatic: WTF is fingerprinting ? 🌀

The other day, I was chatting with an advertiser who asked me:

"The finger-what?"

Fingerprinting is a technique used to identify an online user based on the unique characteristics of their device and browser.

This information can include:

🖥️ Screen resolution
✍️ Installed fonts
🔌 Plugins
🌀 GPU/CPU footprint
🌐 Time zone
📫 IP address
📶 Mobile operator
📱 Phone model
👉 Etc.

On their own, these signals seem harmless. But when combined, they form a unique probabilistic digital fingerprint that tracks the user—without needing any cookies.

But is it actually effective? 🤔

Test it out for yourself:

1️⃣ Go to fingerprint.com: the site will give you a unique fingerprinting ID right on the homepage.

2️⃣ Now: TRY TO SHAKE IT OFF BY ANY MEANS!
🗑️ Delete all your cookies!
🧹 Clear your cache and your history!
🌴 Change your IP address to the Bahamas with a VPN!

And normally, at this point... ⟶ ... ⟶ The tool still manages to identify you! 😲

💡 Fun fact: The only way we found to trick the fingerprinting ID was to use Firefox and crank the security settings up to "Strict". But... that also crashed half the websites we visited 😂

Impressive? Yes. Worrying? A little bit too, but there are safeguards:

⚖️ On the legal side: remember that fingerprinting is still subject to user consent, just like any other advertising identifier.

🍪 The browser fingerprinting ID is mainly used to replace the cookie ID, which was already a unique browsing identifier.

📺 Device-centric: Fingerprinting is inherently tied to the hardware, so cross-device tracking isn't nearly as effective as it is with a deterministic ID.

⚙️ Infrastructure limits: The robustness of a fingerprinting ID varies from one vendor to another. For infrastructure cost reasons, it's highly unlikely that standard market IDs are as advanced as the one on fingerprint.com