Open source

The ThumbmarkJS client fingerprinting library is open source, and will always stay MIT licensed - unlike some that shall not be named.

Best in class

Due to its popularity and being open source, ThumbmarkJS has become the best free client fingerprinting library there is with 90% uniqueness. And with the API, going beyond 99%.

Hugely popular

With +60,000 monthly sites and +1B monthly thumbmarks, you know you're in the right place.