x402 Format Checker

Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402.

IndexedLicense unknown

Install

From the package registry. Read the repository before you give any tool access to your data.

{
  "agentCard": "https://validate.crewofthecaptain.com/.well-known/agent.json"
}

Point an A2A client at this agent card.

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About

Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Send message/send with a data part {"type": "<skill id>", "value": "..."}; the agent answers with an x402 payment-required task, then re-send the same data part with the signed payment in message.metadata (stateless: nothing is stored).

Use cases: api-integration

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Fact sheet

Where you use it: API
Hosting: Hosted by the vendor
Interfaces: a2a
A2A agent card: https://validate.crewofthecaptain.com/.well-known/agent.json

Details

Version: 1.3.0
License: License unknown
Website: validate.crewofthecaptain.com
Docs: validate.crewofthecaptain.com/llms.txt
First seen: Oct 24, 2026
Last checked: Oct 24, 2026
Source: A2A agent card

Cite this page

x402 Format Checker. Agent Mart. https://agentmart.dev/agents/x402-format-checker-validate-crewofthecaptain-com (last updated 2026-10-24)