Verifiers online tools — same implementation for humans and agents · 9 tools
root:verifier·Human page + Agent API · same engine
Luhn algorithm check for card numbers (offline, never stored)
luhn
Validate or calculate the GS1 check digit in bulk: GTIN-8/12/13/14, SSCC-18, GLN-13
gs1-mod10
Validate email format (batch, one per line)
email-shape
Verify HMAC-SHA256 signature matches payload
crypto.createHmac
Validate an IBAN per ISO 13616: structure, per-country length and the MOD 97-10 check digits (offline, never stored)
iban-mod97
Validate CN resident ID check digit (GB 11643)
gb11643
Bulk-validate ISBN-10/ISBN-13 check digits, suggest the correct one, convert 10↔13
isbn-check-digit
Field-level validation of China's 18-character unified social credit code per GB 32100-2015 (ISO 7064 MOD 31-3 check digit, GB/T 2260 division, department and category tables), plus seeded reproducible test-code generation
gb32100-uscc
Validate a 17-character VIN against 49 CFR 565.15 / ISO 3779: length, character set (no I/O/Q) and the position-9 check digit, with the position-by-position math
vin-check-digit
