Official MCP RegistryListed
x402 Format Checker
IBAN, EU VAT, NIP, REGON, PESEL, email checks. Only $0.001 (0.1 cent) per check via x402 on Base
First seen 11 Oct 2026. Evidence as of 6 Nov 2026.
7
Tools
From an anonymous probe
1
Source listings
Each with its own history
3
Recorded changes
Since first seen
Tools
| Tool | Description | Behaviour |
|---|---|---|
| list_types | List the available checks, price, network and payment details (free). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. | Read-only |
| validate_email | Email 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. | Read-only |
| validate_eu_vat | EU 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. | Read-only |
| validate_iban | IBAN: 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. | Read-only |
| validate_pl_nip | Polish 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. | Read-only |
| validate_pl_pesel | Polish 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. | Read-only |
| validate_pl_regon | Polish 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. | Read-only |
Change history
- Website changed from "https://x402-test.crewofthecaptain.com/" to "https://validate.crewofthecaptain.com/" (registry)
- MCP URL changed from "https://x402-test.crewofthecaptain.com/mcp" to "https://validate.crewofthecaptain.com/mcp" (registry)
- Listed (registry)
| Source | Listing | First seen | Last seen | Versions |
|---|---|---|---|---|
| Official MCP Registry | com.crewofthecaptain/format-checker | 11 Oct 2026 | 6 Nov 2026 | 2 |