x402.cron2systemd.dev

x402 payment inspector and related checks

Twenty client-side tools for payment-required headers, payTo, network, USDC amounts, and client checklists. The flagship parses a pasted 402 and can try a CORS fetch. Nothing on this site sends a payment.

Flagship

x402 payment inspector

Parse an HTTP 402 or x402 challenge for network, payTo, asset, and amount. Fetch is best-effort because of CORS.

Parse

payment-required header

Decode a payment-required header from raw JSON or base64 JSON.

Parse

payTo address extract

List every payTo value and checksum 20-byte hex addresses.

Parse

x402 network check

Check a requirement network against a local list of chain ids and known USDC addresses.

Price

Atomic USDC amount

Turn an atomic token amount into a human amount. USDC uses 6 decimals.

Parse

Accept challenge parse

List payment requirements from an accepts array or payment headers.

Price

Resource price table

Table resource, network, and amount from one or more requirements.

Price

Base USDC payTo verify

Check that payTo is an address and the asset matches known USDC for that network.

Parse

Facilitator hint

Show extra facilitator-like fields from a challenge. Does not call a facilitator.

Parse

maxTimeoutSeconds check

Flag a payment timeout under 5 seconds or over an hour.

Parse

MIME type match

Compare the requirement mimeType with the type you expect to receive after paying.

Parse

x402 versus plain 402

Tell an x402 challenge apart from a plain HTTP 402 that has no payment fields.

Probe

Paywall endpoint probe

GET a URL and report whether the browser can see an HTTP 402 challenge.

Probe

Paid 200 versus 402

Compare an unpaid challenge paste with a paid response paste.

Parse

exact scheme / EIP-3009

Check for scheme exact and the extra name/version used with EIP-3009 USDC.

Parse

Paywall header pretty print

Pretty-print response headers from a pasted HTTP message.

Price

Compare resource prices

Compare amounts across several pasted challenges, separated by blank lines.

Probe

llms.txt payment finder

Highlight llms.txt lines that mention 402, x402, or payment. Fetch when CORS allows.

Price

Settlement network mismatch

Flag a requirement whose network is not the network you expect to settle on.

Checklist

x402 client checklist

A local checklist for building a client that can read a 402 and retry after paying.