Coin Tester.

Coin Tester is a Chrome extension that uses acoustic resonance (the ping test) and AI to verify the authenticity of 1 oz gold and silver bullion coins. When a coin is struck, it emits a distinct tone that varies with metal, design, and minting year. The app analyzes this sound and compares it to a growing database of genuine coins to identify counterfeits with high accuracy.

The extension guides users through the verification process and updates its database with new vintages as minting evolves. Subscriptions provide ongoing access for a week, a month, or a year. Current supported gold coins include Britannia, American Eagle, Vienna Philharmonic, Australian Kangaroo, Krugerrand, Canadian Maple Leaf, American Bison, and Australian Emu; silver coins include Britannia, American Eagle, Vienna Philharmonic, Australian Kangaroo, Krugerrand, Canadian Maple Leaf, and Armenian Noah’s Ark.