Observed arrival · 2026-11-03
A preflight check for x402 API payments
x402check offers agents an API for checking an x402 endpoint’s payment details, price history, and uptime before signing a payment.
○Open
⊠Login
$Paid
†Ads
✦Pretty
●Pro
◎Niche
◉Human
⚑Risk
ƒJS
- For
- Agents and developers integrating x402 payments
- Worth noticing
- The homepage reports 16 checks, 3 paid checks, and 2 tools; it says paid counts exclude internal test checks.
Field notes
The documented workflow puts a GET /preflight call before an agent sends PAYMENT-SIGNATURE, with the response carrying payTo, priceUsd, reason codes, and history for that URL. The homepage lists a $0.01 regular check after one free check per wallet, a $0.05 deep check, and a $5 watch option for 30 days. It reports three paid checks on-chain and says those counts exclude internal tests.
Observed signals
Read the marks
Editorial observations of this landing page, not a rating.
○OpenPublic substance visible
$PaidCommerce or pricing visible
✦PrettyNotable craft visible
◎NicheUnusually specific use
One card from the complete issue