Every major website you visit is running hidden tracking scripts in the background. These scripts — known as tracking pixels, analytics tags, and ad pixels — send data about your behaviour back to Facebook, Google, TikTok, LinkedIn, and dozens of data brokers. Most people have no idea how many there are on any given page. Now you can find out in seconds.
What Is a Tracking Pixel?
A tracking pixel is a tiny piece of JavaScript (or sometimes a 1x1 transparent image) embedded in a webpage that fires when the page loads. When it fires, it sends information back to a third-party server — typically an advertising or analytics platform. That information can include your IP address, browser type, device, the page you visited, how long you stayed, what you clicked, and whether you came from another site.
The name "pixel" comes from the original implementation — a 1x1 invisible image that triggered a server request when loaded. Modern tracking is almost entirely JavaScript-based and far more powerful, but the name stuck.
The Most Common Trackers Found on Websites
Facebook Pixel (Meta Pixel)
Installed on hundreds of millions of websites worldwide. When you visit a site with the Facebook Pixel, Meta records that visit and ties it to your Facebook profile if you have one — even if you are not logged in on that browser. This is how Facebook knows to show you an ad for a product you viewed on a completely different website.
Google Analytics and Google Ads
Google Analytics is the world's most widely deployed tracking script — used on over 50% of all websites. It records page views, session duration, traffic source, device type, and user flow through the site. Google Ads tags additionally track conversions, linking ad clicks to purchases across different domains.
TikTok Pixel
Rapidly expanding since 2020. Like the Facebook Pixel, it tracks site visitors and ties that data back to TikTok user profiles for ad targeting. Particularly common on e-commerce and consumer brand sites.
LinkedIn Insight Tag
Common on B2B and SaaS websites. Tracks visitor company, job title, and industry by cross-referencing with LinkedIn profiles — giving site owners demographic data about their visitors and enabling LinkedIn ad retargeting.
Data Broker Scripts
Some tracking scripts belong to data brokers — companies that compile and sell personal data profiles. These are the least visible and most privacy-invasive. They often disguise themselves as performance or analytics tools.
How to Scan Any Website for Trackers
The Anonymiz Tracker and Pixel Scanner detects 50+ tracker types including all the major advertising pixels, analytics platforms, and data broker scripts. To use it:
- Go to anonymiz.com/tracker-scanner
- Enter any website URL — try your own site, a news site, or a retailer
- Click Scan and see every tracker running on that page within seconds
- Results are grouped by category: Advertising/Pixel, Analytics, and Data Broker
Try scanning nytimes.com, forbes.com, or any major e-commerce site. The results are usually eye-opening — most large sites run between 5 and 20 separate tracking scripts.
What Happens to the Data These Trackers Collect?
Each tracker sends data to its own platform, where it is combined with data from every other site running that same tracker. Facebook's pixel data, for example, is combined across all Facebook Pixel-enabled sites to build a comprehensive profile of your browsing behaviour — what categories of sites you visit, what products you look at, how much time you spend, and what you ultimately buy.
This data is primarily used for ad targeting — showing you ads for products you have viewed, predicting what you are likely to buy, and finding other users who behave similarly to you. It is also used for measurement, attribution, and in some cases sold to third parties.
How to Block Trackers
The most effective tools for blocking trackers at the browser level:
- uBlock Origin — the most comprehensive and lightweight tracker blocker available. Free, open source, works on Chrome and Firefox. Blocks most ad pixels and analytics scripts by default.
- Privacy Badger (EFF) — learns to block trackers based on behaviour across sites. Complements uBlock Origin for covering less-known trackers.
- Brave Browser — blocks trackers natively without any extensions. The built-in shield shows you a count of blocked trackers on every page.
- Firefox Enhanced Tracking Protection — enabled by default in Firefox in Strict mode. Blocks known tracking scripts using Mozilla's list.
Why This Matters for Your Own Website
If you run a website, knowing which trackers you have installed matters for two reasons. First, GDPR, CCPA, and ePrivacy regulations require you to disclose third-party tracking scripts and obtain consent before firing most of them. Running Facebook Pixel without a proper cookie consent mechanism is a GDPR violation. Second, trackers add page weight and latency — each tracking script is an additional network request that slows your page load time.
Use the Anonymiz Tracker Scanner to audit your own site and then check the Cookie Consent Checker to verify your consent mechanism is correctly configured.
Frequently Asked Questions
Can websites track me even if I use incognito mode?
Yes. Incognito mode prevents your browser from saving local history and cookies, but it does not prevent tracking pixels from firing. Your IP address, browser fingerprint, and behaviour are still visible to trackers in incognito mode. Only a VPN combined with tracker blocking provides meaningful protection.
How many trackers does the average website have?
Research consistently finds 5 to 15 trackers on average commercial websites. News and media sites often have 10 to 30 — major publishers carry extensive advertising infrastructure. Small personal blogs and open source projects typically have fewer than 3.
Does the scanner see all trackers?
The scanner detects trackers present in the page's static HTML and linked scripts. Some trackers loaded dynamically after user interaction or via tag managers may not appear. For a complete audit of your own site, combine the scanner with a browser-based tool like the Chrome DevTools Network panel.
