Blog
Use-case guides, developer explainers, and technical deep-dives on device signal collection, anti-fraud, and privacy. 16 posts published.
Concept
Browser fingerprinting accuracy is not a single number. It depends on signal entropy, stability over time, and whether matching uses a similarity score or strict equality. This guide breaks down each dimension and the factors that degrade real-world accuracy.
Concept
Looking for a free, open-source browser fingerprinting library you can self-host? This guide covers FingerprintJS OSS, ThumbmarkJS, ClientJS, CreepJS, and ImprintJS side by side on license, cross-browser identity, maintenance status, and best-fit use case, so you can pick the right tool without a sales call.
Concept
FingerprintJS is the most recognized name in browser fingerprinting, but it is not the only option and its most powerful features live behind a paid Pro tier. This guide compares 8 alternatives across licensing, cross-browser identity, anti-spoof detection, and pricing so you can pick the right tool for the job.
Use case
A metered paywall counts free articles in a cookie the reader controls, so clearing site data, opening a private window, or switching browsers hands them a fresh allowance. Keying the meter to a cross-browser hardware fingerprint, which survives all three, makes the meter hold.
Use case
Account sharing is multi-accounting in reverse: one login spread across many physical devices. Counting distinct cross-browser hardware fingerprints per account measures real machines, so one person on two browsers counts once and a sharer who switches browsers does not look like a new device.
Research
Matching the same device across Chrome, Safari, Firefox, and Brave is usually framed as a server-side correlation problem. Partition the signal set by what varies between browsers and the cross-browser identifier becomes deterministic and computable client-side. The hard part is the partition, not the match.
Use case
Referral programs pay real credit per signup, so the dominant abuse is self-referral and referral rings: one person or a handful of devices behind many 'distinct' referees. Cross-browser device matching links the referee back to the referrer and collapses the ring, even across browser switches and incognito.
Use case
Bots and anti-detect browsers are two unrelated threats that a single fingerprint hash misses. Benny returns two independent scores on every call, an automation likelihood for drivers and a spoof likelihood for forged browsers, so you can gate both client-side without a CAPTCHA.
Concept
Most fingerprinting libraries hand you a hash and ask you to write the comparison logic. The six built-in modes in compareFingerprints cover the full range from exact hash equality to hardware-only cross-browser matching, each with fuzzy tolerance, a numeric score, and a diff vector.
Use case
Multi-accounting survives every identity check users control: new email addresses, VPNs, cookie clears, different browsers. A hardware-bound device fingerprint with cross-browser comparison is the durable key that catches the same device regardless of how the account layer is reset.
Concept
Incognito mode prevents cookies and local storage from persisting, but hardware-bound and most engine-bound browser signals are still readable. A well-constructed fingerprint survives private browsing on every major desktop browser, with one notable caveat on iOS.
Concept
A practical comparison of the leading browser fingerprinting libraries. FingerprintJS has the widest signal set, ThumbmarkJS and ClientJS are simple drop-ins, CreepJS is a research tool, and Benny the Doorman adds a cross-browser hardware ID and free anti-spoof. Here is how to choose.
Concept
Cookies are easy to set and easy to clear. IP addresses are free but shared and unstable. Device fingerprints survive cookie clears and browser switches but are probabilistic. This guide compares all three across persistence, cross-browser reach, accuracy, and privacy, and shows when to layer them for durable identity.
Concept
Most fingerprinting libraries return one hash that shifts whenever the browser shifts. Splitting signals into hardware-bound and engine-bound categories produces a second, stable hash that survives browser switches, incognito mode, and cookie clearing on the same physical device.
Use case
Cookie-based trial gates fail the moment a user clears their browser history. A hardware-bound device fingerprint persists through cookie clears, browser switches, and incognito mode, making it the practical foundation for per-device trial enforcement.
Concept
A device fingerprint is a stable identifier derived from the properties a device and browser reveal, hashed into a compact ID that recognizes a returning device without a cookie. This guide covers how they are built, how unique they are, what they are used for, and how to generate one in JavaScript.
