Device fingerprinting is a technique used to create a unique identifier for a device by collecting various subtle signals from its hardware and software. This allows service providers to identify devices without relying on cookies or explicit identifiers, making it a powerful tool in web security and fraud prevention. The technique involves gathering information such as browser type, screen resolution, timezone settings, and other technical artifacts that are unique to each device. Device fingerprinting can be used to detect malicious activity, prevent bot attacks, and enhance authentication workflows, while also raising concerns about user privacy. To implement device fingerprinting responsibly, it is essential to use multiple signals, keep detection methods current, be transparent in data collection practices, and consider using established solutions that maintain privacy standards. As the cat-and-mouse game between security teams and bad actors continues, device fingerprinting remains a vital tool for balancing robust security with user privacy.