x401 Proof Requirement Preflight
Inspect a public x401 proof challenge without sending credentials. Decode PROOF-REQUEST, validate the current 0.2.0 envelope and OpenID4VP request shape, and report concrete interoperability, cache, CORS, and privacy fixes.
Preview request
The preview path is rate-limited and does not charge. It executes the live source and returns the paid response shape while withholding decision-ready values. Production requests use the same parameters and return a standard x402 challenge when no payment signature is present.
curl --request POST \
"https://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/x401_proof_requirement_preflight?preview=true" \
--header "content-type: application/json" \
--data '{"url":"https://example.com/protected","method":"GET"}'Input contract
| Parameter | Type | Required | Description |
|---|---|---|---|
url | string | Yes | Public HTTP or HTTPS route to inspect. No proof or payment credentials are sent. |
method | string | No | GET or HEAD. Defaults to GET. |
Example deliverable
This is the documented response shape, not a promise that live values will match the example. The paid request returns current or declared-source results using the same contract.
{
"success": true,
"assessment": {
"structurally_ready": true,
"decision": "structurally_ready",
"score": 100
},
"proof_summary": {
"scheme": "x401",
"version": "0.2.0",
"request_count": 1,
"protocols": [
"openid4vp-v1-signed"
]
},
"findings": []
}Purchase decision
Buy when: the active task needs this product's structured result, its declared source and freshness are sufficient, and 0.005 USDC is within the buyer's authorized per-request limit.
Skip when: a cached result is sufficient, the source or fields do not satisfy the task, or the buyer has not authorized payment. Do not bypass wallet, budget, or user-approval policy.
Guaranteed response metadata
Every successful product response identifies how the result was produced. Product-specific output fields are documented in the paid OpenAPI contract. The preview proves the live source and field types without returning the paid values.
{
"marketplace_metadata": {
"data_mode": "live_source",
"billable": true,
"availability": "operational",
"source": "live public endpoint probe against the x401 0.2.0 draft specification"
}
}Agent payment flow
Fast path: install the public MCP package, configure a dedicated low-balance Base buyer wallet and a maximum per-request spend, then call this tool with auto_pay: true. The client handles the challenge, local signature, settlement, and retry in one tool call.
npx -y dopaminedesk-ai-data-marketplace-mcp
X402_AUTO_PAY=true
X402_EVM_PRIVATE_KEY=<dedicated buyer wallet key>
X402_MAX_PAYMENT_USDC=0.25
tool input: { "auto_pay": true }Manual path: request the product, read the base64 PAYMENT-REQUIRED challenge, sign with any compatible x402 v2 client, and retry with PAYMENT-SIGNATURE. A successful response includes PAYMENT-RESPONSE.