x402 Format Checker
IBAN, EU VAT, NIP, REGON, PESEL, email checks. Only $0.001 (0.1 cent) per check via x402 on Base
Connect it
Settings → Connectors → Add custom connector
URL: https://validate.crewofthecaptain.com/mcpSettings → Apps & Connectors → Advanced → Developer mode
Create connector with URL: https://validate.crewofthecaptain.com/mcp{
"mcpServers": {
"format-checker": {
"url": "https://validate.crewofthecaptain.com/mcp"
}
}
}claude mcp add --transport http format-checker https://validate.crewofthecaptain.com/mcp{
"servers": {
"format-checker": {
"type": "http",
"url": "https://validate.crewofthecaptain.com/mcp"
}
}
}7 tools, verified live
list_typesread-onlyList the available checks, price, network and payment details (free). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.
validate_ibanread-onlyIBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
validate_eu_vatread-onlyEU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
validate_pl_nipread-onlyPolish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
validate_pl_regonread-onlyPolish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
validate_pl_peselread-onlyPolish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
validate_emailread-onlyEmail address syntax (dot-atom local part, LDH domain; no DNS). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
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