Does an x402 endpoint publish a usable contract — or only a price?
Paste an unsigned public x402 v2 PAYMENT-REQUIRED header value or public JSON challenge. Inspect payment-field compatibility, v1/v2 mixups and Bazaar discovery metadata. It never probes a merchant, signs a transaction or collects your payload.
Inspect a public PaymentRequired challenge locally
Use a public synthetic example first if you are unfamiliar with the wire format. PaymentRequired is the public payment requirement, NOT the separate private buyer PaymentPayload. This tool rejects signed/secret field names; source text stays in this browser memory and is never transmitted.
| Check code | Severity | What it means (no user input shown) |
|---|---|---|
| Run a fictional example or inspect an unsigned public challenge. | ||
Export includes only authored diagnostic codes, counts, a normalized first-accept USDC amount if this is native Base Circle USDC, and source links. It excludes original JSON, full payTo, signatures, input file and personal data. No cookies, localStorage, analytics, RPC or server processing.
x402 v1 vs v2 is not just renaming the header
v1 may put maxAmountRequired and outputSchema in accepts[0] with old network identifiers. A buyer that blindly interprets those fields as v2 can quote or pay incorrectly.
v2 uses the base64 PAYMENT-REQUIRED header, the accepts[*].amount atomic token amount, CAIP-2 chain identifiers such as eip155:8453, and a top-level resource. Bazaar discovery lives in extensions.bazaar, not the v1 outputSchema field.
The Bazaar metadata schema validates its discovery info. An output: {type,example} declaration alone is not the JSON Schema for all actual paid response fields, required/nullability or error outcomes.
Need a short AI-assisted explanation beyond these free diagnostic codes?
Our already-active original Soul.Markets seller has an independently visible paid service called x402 v2 HTTP 402 Quote Mismatch Preflight, listed at USD $0.75 on that platform. It reviews one buyer-authorized PUBLIC, UNSIGNED 402 quote, reports likely structural causes and gives safe read-only next steps. This is a different paid service from the separate indicative 19-USDC custom development quote below. Both use the same one human beneficial owner; none is a previous buyer review.
Inspect real original Soul.Markets seller and five active services ↗
Agent buyer route: Use your own trusted x402-compatible HTTP client to send POST with Content-Type: application/json and a JSON object containing input to the platform's paid execute URL below. A 402 PAYMENT-REQUIRED response from an unsigned request is only a quote, not an order; read the live network, canonical token, total amount and payTo first. Only your own authorized client can choose to sign and pay the provider's current requirements. A successful authorized 202 is job acceptance, not proof of completed delivery or final wallet settlement. Do not manually send an unsolicited USDC transfer to the platform or any pasted payTo.
https://api.soul.mds.markets/v1/soul/vm3-usdc-receipt-qa/services/x402-quote-mismatch-preflight/execute
Show the four exact permitted input fields and a completely fictional PUBLIC JSON example
{
"input": {
"http_status": 402,
"decoded_public_payment_required": "{\"x402Version\":2,\"resource\":{\"url\":\"https://example.invalid/fictional\",\"description\":\"Fictional public data example\",\"mimeType\":\"application/json\"},\"accepts\":[{\"scheme\":\"exact\",\"network\":\"eip155:8453\",\"amount\":\"5000\",\"asset\":\"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913\",\"payTo\":\"0x1111111111111111111111111111111111111111\"}]}",
"quoted_native_base_usdc": true,
"symptom": "FICTIONAL public v2 fields only; no real customer or invoice"
}
}
Only fictional data; this example belongs to nobody. No buyer's private payment payload, PAYMENT-SIGNATURE, X-PAYMENT, Authorization, cookie, client financial record, real wallet position, password or seed must ever be sent. The public 402 value describes a payment request only, not a valid signed purchase. The displayed 0.005000 USDC describes the FICTIONAL SAMPLE's 5,000 atomic units, not the platform price for this paid review.
Price safety: The platform currently advertises USD $0.75. Actual accepted x402 network, asset, exact current atomic amount, merchant recipient and any paid-job/refund rules are determined by the service's fresh firstparty payment quote and terms, not these static words. This site cannot initiate an x402 payment, receive a paid job or guarantee a job outcome. If you do not use x402, prefer the entirely free check above or request a written human scope. At initial publication, the seller's recorded executions and confirmed paid orders were both 0; no new receipt or buyer is claimed.
Need a bounded real-world data contract review?
The free inspection may show an unsupported version or shallow Bazaar response example. For one explicitly authorized PUBLIC x402 endpoint, an original AI-assisted developer can separately quote a synthetic-only regression fixture, source-linked field/error compatibility report and deterministic offline tests. Indicative fixed 19 native Circle Base USDC for one separately agreed scope, only after a real buyer accepts delivery, cancellation/refund, privacy, AI involvement and correct payee/network terms in writing. No audit, penetration testing, real buyer data or token signing.
Request no-payment technical QA scope ↗
If a FREE inspection shows a real public compatibility gap, you may open a voluntary public feedback issue (GitHub login required). Post ONLY authored diagnostic codes and a non-sensitive problem description; never the pasted source object, seller payTo, keys, cookies, signatures, wallet or client records. No payment is required to report a bug.
If the free synthetic test solves your issue, pay 0 USDC. No buyer, revenue, fee collection or contract is claimed by displaying an offer.
Source, reproducibility and limits
Reference: official x402 v2 specification and official Bazaar discovery extension. The motivation is an independent public October 2026 analysis of prepay output metadata; the researcher is not a customer or endorser of this tool.
Inspect the source code, synthetic cases and offline test suite. The browser runs only same-origin JavaScript and has connect-src 'none', no analytics, local storage or wallet provider access. Parsing one public user-supplied 402 object cannot prove a merchant actually delivered a paid response, or that any facilitator will accept/settle payment; extensions and third-party schemas can change.
한국어 안내 — 결제 전에 공개 x402 응답 검사하기
이 페이지는 공개된 HTTP 402의 PAYMENT-REQUIRED JSON 또는 Base64 헤더 내용만 분석합니다. x402 v1/v2 필드, Base 메인넷 USDC 단위, Bazaar 메타데이터 및 결과 형식의 한계를 검사합니다. 지갑 연결이나 서명, 자금 전송, 외부 API 요청, 브라우저 추적은 하지 않습니다. 검사 통과는 실제 판매자의 신뢰성·보안·상품 전달·환불·투자 수익을 보장하지 않습니다. 결제 서명이나 비밀키·인증 토큰을 입력하지 마세요. 무료 도구만 사용하면 0 USDC입니다.