Many people believe they are safe online once they disable cookies, switch on private browsing, or limit app permissions. Yet these steps do not prevent one of the most persistent tracking techniques used today. Modern devices reveal enough technical information for websites to recognise them with surprising accuracy, and users can see this for themselves with a single click using publicly available testing tools.
This practice is known as device fingerprinting. It collects many small and unrelated pieces of information from your phone or computer, such as the type of browser you use, your display size, system settings, language preferences, installed components, and how your device handles certain functions. None of these details identify you directly, but when a large number of them are combined, they create a pattern that is specific to your device. This allows trackers to follow your activity across different sites, even when you try to browse discreetly.
The risk is not just about being observed. Once a fingerprint becomes associated with a single real-world action, such as logging into an account or visiting a page tied to your identity, that unique pattern can then be connected back to you. From that point onward, any online activity linked to that fingerprint can be tied to the same person. This makes fingerprinting an effective tool for profiling behaviour over long periods of time.
Growing concerns around online anonymity are making this issue more visible. Recent public debates about identity checks, age verification rules, and expanded monitoring of online behaviour have already placed digital privacy under pressure. Fingerprinting adds an additional layer of background tracking that does not rely on traditional cookies and cannot be easily switched off.
This method has also spread far beyond web browsers. Many internet-connected devices, including smart televisions and gaming systems, can reveal similar sets of technical signals that help build a recognisable device profile. As more home electronics become connected, these identifiers grow even harder for users to avoid.
Users can test their own exposure through tools such as the Electronic Frontier Foundation’s browser evaluation page. By selecting the option to analyse your browser, you will either receive a notice that your setup looks common or that it appears unique compared to others tested. A unique result means your device stands out strongly among the sample and can likely be recognised again. Another testing platform demonstrates just how many technical signals a website can collect within seconds, listing dozens of attributes that contribute to a fingerprint.
Some browsers attempt to make fingerprinting more difficult by randomising certain data points or limiting access to high-risk identifiers. These protections reduce the accuracy of device recognition, although they cannot completely prevent it. A virtual private network can hide your network address, but it cannot block the internal characteristics that form a fingerprint.
Tracking also happens through mobile apps and background services. Many applications collect usage and technical data, and privacy labels do not always make this clear to users. Studies have shown that complex privacy settings and permission structures often leave people unaware of how much information their devices share.
Users should also be aware of design features that shift them out of protected environments. For example, when performing a search through a mobile browser, some pages include prompts that encourage the user to open a separate application instead of continuing in the browser. These buttons are typically placed near navigation controls, making accidental taps more likely. Moving into a dedicated search app places users in a different data-collection environment, where protections offered by the browser may no longer apply.
While there is no complete way to avoid fingerprinting, users can limit their exposure by choosing browsers with built-in privacy protections, reviewing app permissions frequently, and avoiding unnecessary redirections into external applications. Ultimately, the choice depends on how much value an individual places on privacy, but understanding how this technology works is the first step toward reducing risk.
