CoinAuthenticationApp tests coin grading and authentication apps for collectors who want to know if a coin is real before they buy or sell — not just a fancy photo ID.
Who We Are
Three of us started this project after one team member spent two hours at a coin show trying to verify a Morgan dollar he'd inherited. The seller seemed honest, the coin looked right, but something felt off. He brought it home, checked it against multiple apps, and each one said 'authentic.' Three months later, a real dealer's loupe and a magnifying glass told a different story. The coin was a good fake. None of the apps caught it. We realized that most coin authentication tools test themselves against easy coins — the common dates everyone knows. But counterfeiters don't target common dates. They target the 1893-S Morgan, the 1909-S VDB Lincoln, the Mercury dimes that actually have resale value. We decided to build a review site around that truth.
Our editorial mission is straightforward: coin authentication apps should catch the coins that counterfeiters actually make. We do not grade coins ourselves. We do not authenticate coins for readers. What we do is test whether the apps in the market can spot diagnostic red flags on the coins that matter most — the ones listed in published counterfeit alert bulletins from the major grading services.
Methodology
We maintain a reference set of 34 coins across the most-faked series: 1893-S Morgans, 1909-S VDB Lincolns, 1916-D Mercury dimes, 1921 Peace dollars, certain trade dollars, and key-date Standing Liberties. About half of these coins are documented counterfeits (authenticated as such by dealer networks or previous grading records); the other half are authentic examples that share visual traits with known fakes. We photograph each coin under consistent lighting, upload the images to each app we review, and record whether the app flags any red flags, shows hesitation, or gives a confident 'authentic' verdict. We also test with lower-resolution images to see how gracefully an app handles poor photo quality — many fakes are sold online in dim light. Each full review takes 30 to 60 hours spread over four weeks, including research into the specific diagnostic features of each counterfeit type.
We re-test each app after a major update, and we rotate our test set every two quarters to add newly counterfeited coins as they appear in the market. We evaluate apps on five criteria: (1) diagnostic accuracy on our reference counterfeits; (2) specificity — whether the app names the actual problem ('planchet thickness', 'die crack pattern', 'strike doubling') or just says 'suspicious'; (3) honesty about grade and potential cleaning damage, since many counterfeits are cleaned or altered; (4) offline functionality, since collectors may be at shows or remote locations; and (5) whether the app acknowledges uncertainty when it should — a 95% confidence verdict on a borderline coin is worse than a 60% verdict with explanation.
Our Standards
We believe a coin authentication app is only as good as its ability to spot the coins that counterfeiters actually make, not the coins everyone already knows are authentic. We test apps against a small canon of the most-faked U.S. coins — the 1893-S Morgan, the 1909-S VDB Lincoln, key Mercury dimes, and Peace dollars — because these are the coins that move at auction and in dealer networks. An app that can identify a 2020 state quarter is useful; an app that catches a convincing counterfeit 1916-D Mercury dime is trustworthy. We also care deeply about whether apps disclose cleaning and damage issues. A counterfeit often carries the fingerprints of deception: tool marks from die alteration, planchet seams that don't match the period, strike characteristics that betray a modern die. A good authentication app will point these out. A mediocre one will miss them and hand the collector false confidence. We score apps that admit uncertainty — that say 'this image is too grainy to verify' or 'this could be a late-strike variant, consult a dealer' — above apps that force a verdict when the evidence is mixed.
Disclosure
We do not authenticate coins for readers — if you have a coin you're unsure about, take it to a dealer or grading service, not to our site; we do not accept paid placement from app developers or coin services, and we do not grade, slabbed or raw, any coins sent to us; we do not test counterfeit-detection features we cannot verify independently against our reference set, which means we do not review apps focused on ancient, world, or medallion coins outside the U.S. bullion and numismatic canon that has published counterfeit bulletins.
Contact
If you're a developer and believe your authentication app should be reviewed, or if you've spotted a counterfeit that deserves attention in our test set, we invite you to contact us through the form on this site. We read every message and typically respond within one week.