TL;DR
FingerprintJS produces a single hash from forty-three signals. Benny tags every signal as hardware or engine and produces two hashes (a per-browser fingerprint and a deterministic cross-browser hardware ID), plus a comparison API with six modes and a 16-check anti-spoof consistency engine. All client-side. No account.
FingerprintJS Pro still wins for teams that need server-resolved persistent identity, IP intelligence, velocity rules, or native mobile SDKs. Those are server-side features, and a pure client library can't replicate them.
If you're building anti-fraud or personalization and want a tool that does fingerprinting well, not a device-intelligence platform with a sales contract and a feature checklist, Benny is the cleaner fit. FingerprintJS is the platform play.
Architecture: one hash vs two
FingerprintJS produces a single Murmur hash from a flat list of 43 signals. Same device on Chrome and Safari? Two different hashes. The OSS library has no way to know it's the same device. That capability is gated to Pro and requires a server roundtrip to resolve.
Benny tags every signal as either hardware (motherboard, CPU, GPU, audio chip, all invariant across browsers on the same machine) or engine (browser-specific quirks). You get two hashes: fingerprint (full, per-browser) and hardwareFingerprint (deterministic, cross-browser).
Same device, three browsers, three different fingerprint values, but one identical hardwareFingerprint. Client-side, no server, no fuzzy match. This is the wedge.
Comparison API: ship it or build it
FingerprintJS hands you a hash and walks away. If you want to ask "is this the same device that signed up an hour ago?", you write that comparison code yourself. If you want to ask "is this the same device on a different browser?", you can't do that without Pro's server.
Benny ships compareFingerprints with six modes: exact, cross-browser, hardware-only, engine-only, strict, lenient. Each returns a weighted similarity score, constraint violations, fuzzy matches on screen and audio, and a numeric diff vector ready for ML downstream.
For most anti-fraud and personalization use cases, the comparison logic is the actual product. Benny gives it to you for free.
Anti-spoof: free vs paid
FingerprintJS's anti-detect and tampering detection live in Pro, behind tampering_ml_score and friends. The OSS library has none of it. That's by design, meant to push you toward the paid tier.
Benny's consistency block on every fingerprint result carries a score, a list of flags, and a spoofLikelihood rating (low / medium / high). It runs 16 rule-based checks (not ML) and is honest about what it catches. It detects spoofed user agents, automation attributes, anti-detect-browser signatures, inconsistent claimed-vs-actual hardware, engine-vs-UA cross-checks, a dual-source font-OS plausibility pair, and canvas/audio statistical-uniformity classifiers that distinguish algorithmic noise patterns from legitimate browser farbling.
It's narrower than Pro's ML pipeline. It also ships in the free tier.
Focused tool, not a platform
FingerprintJS Pro is a full device-intelligence platform. It bundles fingerprinting with IP intelligence, velocity signals, aggregate ML, native mobile SDKs, webhooks, and backend SDKs in Python, Go, PHP, and Java. If you need the full bundle, that's a real product. The price reflects it.
Benny is fingerprinting and nothing else. The cross-browser hash. The comparison API. The consistency engine. Three primitives that compose into whatever you actually need.
Most teams don't need the full platform. They need fingerprinting that works, integrates in five minutes, and doesn't require a sales call. If that's your use case, Benny is the cleaner fit. If you're at the scale where you need persistent IDs, IP intel, and an SLA-backed vendor relationship, that's FingerprintJS Pro territory, and that's a fair trade.
Signal coverage: where Benny is behind
FingerprintJS has 43 signal collectors. Benny has 21 today. Recent releases closed a lot of the gap. Specific collectors Benny still doesn't have: vendor_flavors, private_click_measurement, dom_blockers, the full CSS media-query suite (prefers-contrast, any-hover, inverted-colors), UA-Client-Hints high-entropy hints, and the 3-attribute touch-support combo.
Two FingerprintJS techniques were evaluated and deliberately rejected: their Safari 17 audio randomization bypass (Apple arms-race exposure and no customer demand, since Safari users are already strongly identified via hardwareFingerprint) and scheme flooding (a predatory-fingerprinting technique that undermines our no-default-telemetry stance, given that hardwareFingerprint already covers cross-browser device-ID).
In exchange, Benny captures signals FingerprintJS deliberately skips: WebGPU support and shader trace, WebGL pixel readback (they only read getParameter constants), speechSynthesis.getVoices(), navigator.mediaDevices.enumerateDevices(), navigator.storage.estimate() quota, WebRTC SDP codec metadata (no network I/O), a Permissions API entropy probe, and an error-stack engine-classifier that compounds with other engine-vs-UA checks for multiple independent engine-reveal vectors.
FingerprintJS reads what the browser reports. Benny measures what the hardware does. Different philosophies, different entropy.
Where Benny doesn't compete
Persistent server-resolved visitor_id: Pro's fuzzy-match engine recognizes the same device weeks later across browser updates, IP changes, and cleared cookies. A client-only library can't do this without a server. If you need cross-session identity that survives full state wipe, you need Pro.
IP intelligence (geo, ASN, datacenter detection, VPN/Tor blocklists), velocity signals (distinct-IPs-per-visitor in rolling windows), aggregate ML trained across customers, native mobile SDKs (Frida detection, jailbreak/root, emulator detection): all server-side or platform-native. Benny will not have these.
