Identifier Validator + Stablecoin Peg Verdict

Offline IBAN/BIC/EU VAT/card/ISBN/GTIN validators + live USD stablecoin peg-health verdict.

Paid verification

No sponsored paid call yet.

Pay this endpoint once from your own wallet (Base USDC, up to $1.00) and we call it and record what came back. Your wallet pays the listed recipient directly; Agent Tools never holds funds. Sponsored checks prove delivery; they do not count as demand.

Quality grade

How grading works

B 56.8 / 100

Availability 20.0 / 20

Endpoint responded (HTTP 200)

Payability 15.0 / 15

✓ Answers a real HTTP 402 challenge
✓ Publishes a /.well-known/x402 descriptor
✓ Payment address on record
✓ Settlement network declared
✓ Price declared

Demand 0.0 / 35

0 distinct payers, 0 USDC transfers in the last 30 days

Performance 8.8 / 10

Last probe answered in 424 ms (full marks at 200 ms or less)

Readiness 13.0 / 15

Agent readiness 87/100

Owner verified 0.0 / 5

Nobody has claimed this listing yet

Endpoint last checked 20 h ago. On-chain activity last read 3 d ago. Availability and on-chain demand are both re-probed daily; the grade updates automatically on the next pass. This grade sets search order and leaderboards; the readiness score below is shown for reference only.

x402 readiness

B · 87/100

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here B, 56.8/100), which weighs availability, payability and on-chain demand. How the two differ

Valid payment requirements	10/10	Payment requirements carry a payee, a mainnet network and a price.
Live 402 challenge	20/25	Endpoint reachable; its 402 challenge was seen earlier (424 ms).
x402 version	n/a	x402 version not observed yet.
Signed descriptor	n/a	No x402 standard defines a signed descriptor.
Uptime (30 days)	15/15	11/11 probes succeeded over 30 days (100%).
Resource declaration	10/10	Declares 8 paid resource(s).
Verified identity	5/10	Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
Freshness + modern flags	5/5	seen in a source within 7 days; declares x402.
Security declaration	n/a	Payment is the access control for an x402 resource.

Applicable criteria total 75 points, scaled to 100.

Responsiveness: Responsive (424 ms; bands ≤2.5 s, ≤5 s, ≤8 s, slower; penalty only).

Payment evidence: x402_challenge — We sent a request and got a live HTTP 402 challenge. Also: x402_manifest. Qualifies the payment claim; adds no points.

Measured 2026-11-11.

Nine criteria, the same as the A2A readiness score, read from our daily probe of the paid endpoint, its payment requirements and 30-day probe history. Signed descriptor and security declaration are n/a for x402 (payment is the access control), as is an x402 version we have not observed; the remaining points are scaled to 100. Grades: A>=90, B>=75, C>=60, D>=40, F<40. It also feeds 15 points of the x402 quality grade.

Compared with peers

Against 10,082 reachable x402 APIs in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.

Readiness: Higher than 75% of peers; This listing 87 · peer median 78
Latency: Faster than 25% of peers; This listing 424 ms · peer median 205 ms

Where it loses the most points, and how to win them back

Live 402 challenge −5 — Answer the paid path with a valid 402 challenge.
Now: Endpoint reachable; its 402 challenge was seen earlier (424 ms).
Verified identity −5 — Claim the listing and prove control of its domain.
Now: Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.

How many agent tools actually work · All statistics

Paid endpoints

8 resource(s) advertised by this origin. Each price below is that resource's own x402 price; the headline price is the range across them.

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/iban?iban=DE89370400440532013000

Validate an IBAN (country rules, length, BBAN structure, mod-97) - returns validity, country, SEPA flag, formatted IBAN

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/bic?bic=DEUTDEFF

Validate a BIC/SWIFT code - returns structure, country, location and branch

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/vat?vat=DE811569869

Validate an EU/EEA VAT number format and checksum offline

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/card?number=4111111111111111

Validate a payment card number (Luhn + network detection); returns masked output only

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/isbn?isbn=9780306406157

Validate ISBN-10/13 and convert between them

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/gtin?code=4006381333931

Validate GTIN-8/12/13/14 (EAN/UPC) check digit

GET https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/stablecoin-peg?asset=USDC&chain=Base

Stablecoin peg-health verdict (PEGGED/WATCH/DEPEG_RISK/DEPEGGED) with 0-100 risk score, price deviation in bps, 1d/7d/30d supply flows and per-chain liquidity, computed live from DefiLlama. asset=USDC[&chain=Base]; up to 10 comma-separated assets per call.

POST https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/batch

Validate up to 25 mixed identifiers in one call

How to call

cURL · x402-fetch / x402-axios will auto-handle 402

curl -sS -i -X GET 'https://identifier-validator-api.yuechenxi-importexport.workers.dev/x402/v1/iban?iban=DE89370400440532013000'  # expect HTTP 402 Payment Required (about 0.002 USDC/call)

MCP endpoint

https://identifier-validator-api.yuechenxi-importexport.workers.dev/mcp

/.well-known/x402.json

https://identifier-validator-api.yuechenxi-importexport.workers.dev/.well-known/x402

Listed in

Directories this entry was found in.

mcp since 2026-11-01