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x402 Data Lookups: domains, US federal awards, clinical trials, FDA drugs/adverse events/recalls, PubMed

https://x402-domain-check.vercel.app/domain/check
● healthy search

Pay-per-call JSON lookups via x402 (USDC on eip155:8453, payTo 0x94D642596761470161B37771FAC222111A5FfAd6). No account or API key; failed upstream calls are not charged.

Category
search
Chains
base, eip155:8453
Price
$0.0100–$0.0200 USDC

Quality grade

How grading works
B+ 68.8 / 100
Availability 20.0 / 20
Endpoint responded (HTTP 402)
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 10.2 / 35
5 distinct payers, 26 USDC transfers in the last 30 days
Performance 10.0 / 10
Last probe answered in 182 ms (full marks at 200 ms or less)
Readiness 13.6 / 15
Agent readiness 91/100
Owner verified 0.0 / 5
Nobody has claimed this listing yet
Endpoint last checked 19 h ago. On-chain activity last read 35 h 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

A · 91/100

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+, 68.8/100), 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 25/25 Paid endpoint answers with an HTTP 402 challenge (182 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 17/17 probes succeeded over 30 days (100%).
Resource declaration 8/10 23 paid resources; 23 sampled lack a description.
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 (182 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, bazaar_feed, catalog_listing. 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 90% of peers
This listing 91 · peer median 78
Latency
Faster than 56% of peers
This listing 182 ms · peer median 205 ms

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

  • 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.
  • Resource declaration −2 — Declare each paid resource with its input and output schema.
    Now: 23 paid resources; 23 sampled lack a description.

How many agent tools actually work · All statistics

Paid endpoints

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

https://x402-domain-check.vercel.app/domain/check
https://x402-domain-check.vercel.app/federal/awards
https://x402-domain-check.vercel.app/trials/search
https://x402-domain-check.vercel.app/fda/drug
https://x402-domain-check.vercel.app/fda/adverse-events
https://x402-domain-check.vercel.app/fda/recalls
https://x402-domain-check.vercel.app/pubmed/search
https://x402-domain-check.vercel.app/sanctions/search
https://x402-domain-check.vercel.app/sec/company
https://x402-domain-check.vercel.app/sec/insiders
https://x402-domain-check.vercel.app/econ/treasury
https://x402-domain-check.vercel.app/census/area
https://x402-domain-check.vercel.app/providers/npi
https://x402-domain-check.vercel.app/drugs/price
https://x402-domain-check.vercel.app/buyers/award-history
https://x402-domain-check.vercel.app/opportunities/search
https://x402-domain-check.vercel.app/opportunities/changes
https://x402-domain-check.vercel.app/codes/icd10
https://x402-domain-check.vercel.app/codes/hcpcs
https://x402-domain-check.vercel.app/medicare/fee-schedule
https://x402-domain-check.vercel.app/security/vulns
https://x402-domain-check.vercel.app/hospitals/ratings
https://x402-domain-check.vercel.app/grants/search

How to call

cURL · x402-fetch / x402-axios will auto-handle 402
curl -sS -i -X GET https://x402-domain-check.vercel.app/domain/check  # expect HTTP 402 Payment Required (about $0.01/call)
/.well-known/x402.json
https://x402-domain-check.vercel.app/.well-known/x402

Listed in

Directories this entry was found in.

cdp-bazaar since 2026-10-27 x402scan since 2026-10-27