Discover / x402-test.crewofthecaptain.com

x402 Format Checker

□ No challenge detected

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. POST JSON {"value": "..."}; values are never stored and personal identifiers are masked. Also a remote MCP server (/mcp) and A2A agent (/.well-known/agent-card.json).

x402
Base
USDC
Verification

Listed price: $0.001
Challenge detected: 0 of the last 4 checks
Last checked: 18 Oct, 03:20 UTC
In our index since: 14 Oct 2026

Endpoint

curl -i https://x402-test.crewofthecaptain.com
# 402 Payment Required: pay with an x402 client (USDC on Base),
# then send the same request again with the payment attached.

Agents can find it through the Superstables MCP server and JSON API: GET /api/v1/services/x402-test.crewofthecaptain.com

Recent checks

14 Oct 2026One bar per check, showing up to 20 recent checks. Coloured bars show relative response time, with a minimum visible height; full-height grey bars mean no challenge was detected. “Challenge detected” means HTTP 402 or another detected payment-challenge signal.18 Oct 2026

All 4 checks

When (UTC)	Result	HTTP	Response
18 Oct, 03:20 UTC	No challenge detected	200	204ms
16 Oct, 21:20 UTC	No challenge detected	200	291ms
15 Oct, 15:20 UTC	No challenge detected	200	104ms
14 Oct, 12:22 UTC	No challenge detected	200	188ms

Questions

Did our last probe detect a payment challenge?

No. At our last probe on 18 Oct, 03:20 UTC, we detected no payment challenge.

What price is recorded for x402 Format Checker?

Its listed price is $0.001.

What payment terms does x402 Format Checker advertise?

The listing advertises x402, Base and USDC. Check the seller's current payment challenge and authentication requirements before paying.

Where is x402 Format Checker listed?

In x402-list.com. Superstables first indexed it on 14 Oct 2026.

Something wrong on this page? Tell us.