keyronne.com/api/book

proceed grade A Book Lookup by ISBN Base found on CDP Bazaar delisted confidence 1.00
https://keyronne.com/api/book

As of 2026-08-15, keyronne.com/api/book on Base held a near-perfect 99.5% uptime across 576 reliability checks over the past 30 days. Responses came back sluggish at 767 ms average from a single EU vantage point (so this includes network distance to the endpoint) and it has held its advertised price steady at $0.0040. Its x402-trust grade is A (score 80.9 from a solid sample, tracked for 38 days), so it currently looks safe to use. It is no longer listed in the x402 directory.

Advertised descriptionLook up a book by ISBN (10 or 13 digit): title, subtitle, authors, publishers, publish date, page count, subjects, and cover image. Validates the ISBN check digit first (rejecting typos unpaid) and returns both ISBN forms. Data from Open Library; attributed in every response. POST a JSON body like: {"isbn":"9780140328721"}(Provider-supplied: an unverified claim, not checked by us. The trust grade above is our independent measurement.)
⏱
Cached snapshot, computed 44 hours ago. This is the full-density trust score computed from every probe, same as the paid API... but it may be up to 24 hours old. For a guaranteed-current answer it re-probes the endpoint live at the moment you ask, adds a confidence band, the full component breakdown, structured risk flags and on-chain settlement proof:
Browser wallet payment, no code required. Agents use POST /v1/x402-trust or the x402_trust_score MCP tool.
30-day uptime
99.5%
Avg latency (EU)
767 ms
moderate · from EU vantage
Confidence
1.00
full-density score
Advertised price
$0.004
USDC
Price stability
Stable
last 30 days
Probes (30d)
576
full record · up to 48/day

Latency is 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.

Full observation record ▾
Trust gradeA (score 80.9)
Recommendationproceed
Confidence1.00, full-density (every probe in the 30-day window)
30-day uptime99.5%
Avg latency (EU vantage)767 ms
Probes (30d)576
Advertised price$0.004 USDC
Price stability (30d)stable
Networkeip155:8453
First seen2026-07-08
Last probed2026-08-13
Statusdelisted
Snapshot computed2026-08-13 22:09 UTC
This is the free cached snapshot. Here's what the paid API adds.
  • ✓
    Live probe at decision time:
    We re-check the endpoint the moment you ask (timestamped) and compute the score from all scores up until this moment, instead of this cached snapshot that may be up to 24h old.
  • ✓
    Confidence band, full component breakdown & structured risk flags:
    Exactly why the score is what it is, machine-readable.
  • ✓
    On-chain settlement proof:
    Real USDC volume & distinct-payer count for the payTo wallet: is anyone actually paying it?
  • ✓
    90-day raw history:
    Every listing/price/payTo change and probe result (via POST /v1/x402-history), up to 90 days back.
  • ✓
    The ranked better-scored alternatives:
    The resource URLs, scores & prices we don't reveal above (via POST /v1/similar), if there are better alternatives available.
  • ✓
    Change & liveness alerts:
    Get notified on payTo/price changes, spec regressions or downtime (via POST /v1/watch-endpoint-30d). Connect up to 10 Discord / Slack webhooks or poll regularly with bearer auth. Increases probe-density to every 5 minutes instead of the usual 30 for the watched endpoint.

... Simply give your agents the tools to do all of that for you, with a simple command
$npx -y x402-trust-mcp

Prefer HTTP? Call POST /v1/x402-trust directly (pay-per-call over x402, from $0.005).