Canonical JSON (RFC 8785 JCS) and SHA-256

avoid grade F Base found on thirdweb found on PayAI confidence 0.66
https://x402-catalog-history.ai-business-surface.workers.dev/json-canonical
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Advertised description
Canonicalize JSON before you hash, compare or sign it: one POST takes a JSON string or any JSON value and returns the RFC 8785 (JCS) form, its SHA-256 and its UTF-8 byte length. Object keys are ordered by UTF-16 code…Show more ▾Show less ▴Canonicalize JSON before you hash, compare or sign it: one POST takes a JSON string or any JSON value and returns the RFC 8785 (JCS) form, its SHA-256 and its UTF-8 byte length. Object keys are ordered by UTF-16 code units, strings use minimal escaping, numbers use ECMAScript Number::toString, and arrays keep their order. Duplicate keys, NaN, Infinity, trailing commas and a lone surrogate are refused with 400 before any payment; integers outside +-2^53 come back with a number_precision_loss warning instead of being silently rounded. input_sha256 is the hash of the json as supplied, so it differs from sha256 when only whitespace or key order changed. The value is not stored, no URL is fetched and nothing is signed or transferred. curl: POST /json-canonical -H 'content-type: application/json' -d '{"json":"{\"b\":2,\"a\":1}"}' . Response: {canonical, sha256, bytes, input_sha256, warnings[], canonicalization, limits, paid, delivery}. No keys, no account, one POST, one delivery - 0.002 USDC. A purchase is two calls by design: this first call returns 402 with the price and the payment terms, and you then repeat the same request with the PAYMENT-SIGNATURE header to receive the 200 delivery.
(Provider-supplied: an unverified claim, not checked by us. The trust grade above is our independent measurement.)
30-day uptime
2.0%
Avg latency (EU)
342 ms
moderate · measured from a single EU vantage point; includes network round-trip distance to the endpoint; a geographically distant endpoint reads slower even when its server is fast, so it is only lightly weighted in the score
Confidence
0.66
full-density score
Advertised price
$0.002
USDC
Price stability
Stable
last 30 days
Probes (30d)
50
full record · up to 48/day
More details ▾
Endpoint ID273588
Pay on Base$0.002 USDC · to 0x6f60…89c3 ↗
First seen2026-10-19
Last probed2026-10-30
Statuslisted
Snapshot computed2026-10-30 06:47 UTC (free snapshot, recomputed at least every 24h)
Why this verdict?5 error flags1 warning
A wallet payment page opens first; approve the USDC payment and the full JSON report loads right in your browser. Want a taste first? Read a free full sample report.
This page is the free cached snapshot (computed 6 hours ago, refreshed at least every 24h). Here's what the paid API adds.
  • ✓Live re-probe at decision time
    The score is computed the moment you ask, not up to 24h ago.
  • ✓Instant snapshot refresh
    Every paid call rewrites this page, the badge and the card immediately.
  • ✓The full “why”, machine-readable
    Confidence band, component breakdown, every risk flag with its evidence.
  • ✓On-chain settlement proof
    Real USDC volume and distinct payers behind the pay-to wallet.
  • ✓90-day raw history
    Every listing, price and payTo change, every probe result.
  • ✓Ranked better alternatives
    Higher-scored endpoints serving the same function, when they exist.
  • ✓Change & liveness alerts
    PayTo/price moves, spec regressions, downtime; 5-minute probes while watched.
$npx -y x402-trust-mcpGive your agents the tools to do all of this for you, with one install. Agents use the x402_trust_score MCP tool or POST /v1/x402-trust directly (pay-per-call over x402, from $0.005).