Device fingerprinting
Also known as: browser fingerprinting, canvas fingerprinting, probabilistic matching
Device fingerprinting recognises a returning visitor by combining traits their browser exposes anyway, such as screen size, fonts, time zone and how their graphics stack draws a test image. Nothing is stored on the device, which is precisely why clearing cookies does not defeat it.
Why do tracking tools reach for fingerprinting?
Because it survives everything that killed cookies. Browsers cap cookie lifetimes and shoppers refuse storage, but a device still has a screen size and a time zone. Fingerprinting recovers matches those limits removed, which is why accuracy claims that look impossible are often built on it.
Is device fingerprinting being shut down?
It is being narrowed, deliberately and from several directions at once. Safari and Firefox both reduce what a page can learn about the machine specifically to make devices harder to tell apart, and they treat fingerprinting as circumvention rather than as a feature to support.
What does wesaw do today?
wesaw recognises a returning visitor from a first-party identifier the shop's own server issues, and matches the visit to the order the shop already recorded. No canvas, no WebGL, no disguised equivalent is used today. That is a statement about the product as it stands on 25 August 2026, not a promise about every version that follows: what wesaw does commit to is that the method behind any number is published on the method page before the number is, and that anything it cannot witness is labelled as such instead of being modelled.
Sources
- Safari and Firefox both reduce the information a page can read about the device in order to make fingerprinting harder, and treat it as a circumvention technique rather than a supported one.Mozilla
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