| Availability (valid 402 returned) | 100.0% of 61 probes · single vantage |
| Median 402 handshake | 112ms |
| p90 handshake | 149ms |
| Catalog price (advertised) | $0.05 |
| Live price (median demanded) | $0.05 |
| Price status | match |
| Protocol | x402 v2 |
| Category (our classification) | commerce-payments |
| Payment receiver | 0x5B4A…0EA1 · stable since Jul 12 |
| Base USDC inflow to this receiver wallet (30d, all sources — not just x402) | none observed |
| Discovery (.well-known/x402) | present |
| Catalog volume (their metric) | 1 calls/30d |
| /check | $0.02 | $0.02 (matches) |
| /extract | $0.005 | $0.005 (matches) |
| /resolve | $0.005 | $0.005 (matches) |
| /attest-delivery | $0.05 | not yet probed |
grade evidence: hourly probes of /attest-delivery. Availability, latency and protocol measure the operator's shared infrastructure and generalize across its products; the price check applies to the probed product. We now also probe one other product per hour, rotating; "live price we measured" shows what each answered.
Signed delivery receipts for agentic commerce: submit what a paid service returned (plus its x402 settlement receipt and advertised schema) and receive an offline-verifiable Ed25519 attestation binding payment to delivery to grounded content — schema …
What this grade does and doesn't measure: it scores the paid-request handshake — whether the service returns a spec-valid 402 payment challenge, how fast, and whether its price is honest. We do not pay these endpoints yet, so we do not verify that the paid response returns correct or complete content. Availability is a probe success rate measured hourly, from a single network vantage for this service.
Operator of groundcheck.seiche.info? Dispute this rating. Scores are opinions based on automated measurements at the stated times.