Product review

FingerprintJS (open source) device fingerprinting review

FingerprintJS is an open-source client-side library that derives a visitor identifier from browser attributes. It is separate from Fingerprint’s hosted identification product: collecting a local identifier does not provide the hosted server matching or entitled Smart Signals.

By Nathan Brooks · Updated October 23, 2026

7.3 / 10

Editorial score

Evidence layer: Self-hosted browser fingerprint library
Free access: MIT-licensed self-hosted library
Paid entry: No hosted identification fee; hosting and engineering costs apply

Visit FingerprintJS (open source) Compare all eleven

Key facts

Identity and matching scope: FingerprintJS is an open-source client-side library that derives a visitor identifier from browser attributes. It is separate from Fingerprint’s hosted identification product: collecting a local identifier does not provide the hosted server matching or entitled Smart Signals. Vendor page ↗
Result to inspect: Client-generated visitor identifier and components Vendor page ↗
Access and pricing: Open-source library. No hosted subscription for the library; operating work is yours. Compare the actual plan, product and usage unit. Vendor page ↗
Developer evaluation: Evaluate known repeat visits and different browsers separately. Include cleared storage, privacy settings, browser upgrades, shared devices, missing collection and delayed results. Inspect the returned identifiers and reasons before connecting them to an account action. Vendor page ↗
License and scope: The current repository lists an MIT-licensed client-side library that hashes browser attributes. It is distinct from the commercial hosted Fingerprint service. Vendor page ↗

Strengths

Source code and API usage are publicly inspectable.
A local prototype can run without a hosted identification subscription.
Components can help explain which browser observations changed.

Limitations

Client-generated output can be modified or replayed and needs a trusted application design.
Matching persistence, risk enrichment and production maintenance remain separate implementation work.

Who it fits

Teams that want inspectable client collection and can own matching, integrity controls and maintenance.

Use the alternatives by evidence layer to compare identification services, risk platforms, consortium reputation and self-hosted libraries.

What the score means

The 7.3 out of 10 score is an editorial assessment under the same 41-criterion, seven-category framework. The rubric emphasizes persistence, collision control, anti-spoofing and usable risk context. The published scale runs from 0 to 10.

The award and score are distinct. Read all criteria and relative weights and verify the required signal and integration for your traffic.

How to evaluate it

Evaluate known repeat visits and different browsers separately. Include cleared storage, privacy settings, browser upgrades, shared devices, missing collection and delayed results. Inspect the returned identifiers and reasons before connecting them to an account action.

Maintainer’s browser demo

Open the maintainer demo and compare your own permitted browser sessions; keep the open-source output separate from the commercial product.

Open evaluation route

Sources and further reading

Product and detection approach · checked October 23, 2026
Pricing and access · checked October 23, 2026
Integration and result documentation · checked October 23, 2026
Maintainer guide: library scope and limitations · checked October 23, 2026

FAQ

What does FingerprintJS (open source) return?

Client-generated visitor identifier and components. FingerprintJS is an open-source client-side library that derives a visitor identifier from browser attributes. It is separate from Fingerprint’s hosted identification product: collecting a local identifier does not provide the hosted server matching or entitled Smart Signals.

Who should evaluate FingerprintJS (open source)?