Solo dev builds browser fingerprint tool with Claude Code

Security engineer David Dale released Glassbox, a browser fingerprinting tool that runs entirely client-side and checks more than 30 tracking methods without sending any data to a server. It sits alongside established privacy checkers like AmIUnique and the Electronic Frontier Foundation's Cover Your Tracks, but differs by keeping every result on-device instead of logging to a remote database.

Glassbox scores a browser's identifiability on a 0-100% scale using entropy calculations across canvas rendering, WebGL, installed font libraries, WebAssembly feature support, and cross-site login state. It also flags less common vectors, including a silent sawtooth audio wave technique first spotted on AliExpress, used to fingerprint visitors through subtle differences in how their browser processes audio.

Dale, working solo, credited Claude Code with cutting the time it took to move from an internal prototype to a public release. "Tools like Claude Code have made it much easier to polish ideas and offer the useful ones to a wider audience," he said.

For developers building anything that touches user tracking or consent, an ad-supported side project or a compliance-sensitive SaaS product, Glassbox is a fast way to check which of a site's own scripts are contributing to a visitor's fingerprint, without shipping any of that data off-device to do it. It doubles as a case study in how far a solo security project can go when an AI coding agent takes on the polish pass alongside the first draft.