What is canvas fingerprinting?

Canvas fingerprinting uses the HTML5 Canvas API to identify browsers. When a website draws an image or text using Canvas, subtle differences in GPU hardware, graphics drivers, operating system, and font rendering produce slightly different pixel-level output on every device. The website reads these pixels, hashes them, and uses the hash as a device identifier. It is one of the most reliable fingerprinting vectors because: 1) It is difficult to disable without breaking websites that legitimately use Canvas (games, charts, image editors). 2) The output is deterministic per device — the same device always produces the same hash. 3) It provides 10-15 bits of entropy, enough to significantly narrow down identity when combined with other signals. Anti-detect browsers counter canvas fingerprinting by injecting controlled noise into Canvas outputs. Each browser profile produces consistent noise (same noise every time within a profile) but different noise between profiles. This makes each profile appear unique while maintaining consistency within sessions. Testing your canvas fingerprint: sites like BrowserLeaks.com and AmIUnique.org show your canvas hash and compare it against their database of known fingerprints.