What is device fingerprinting on mobile?

Mobile device fingerprinting identifies smartphones and tablets through hardware and software attributes, similar to browser fingerprinting but with additional mobile-specific vectors. Mobile-specific vectors: device model and manufacturer (via user agent and JavaScript), screen resolution and pixel density, installed fonts (more limited on mobile, but still differentiating), sensor data (accelerometer, gyroscope calibration data is unique per device), battery status API (charge level and charging state), audio context (audio processing characteristics), available media codecs, and cellular network information (carrier, connection type). iOS vs Android: iOS provides less fingerprinting surface than Android due to Apple's privacy restrictions. All iPhones of the same model report similar attributes, making individual identification harder. Android devices vary more in configuration, making fingerprinting more effective. Mobile app fingerprinting adds: device ID (Android ID, IDFA before iOS 14.5), installed app list (Android only), file system artifacts, and hardware serial numbers. These are far more reliable than web-based fingerprinting. Defense: for web browsing, anti-detect browsers on mobile are less mature than desktop. For app-based fingerprinting, device farms with unique devices per account are the gold standard. Virtual devices (emulators) are detectable and should be avoided for serious operations.