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x402 Pre-Payment Safety Check
x402
x402 Pre-Payment Safety Check is a paid API for AI agents from kr-x402-mvp.kgy5612.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).
Fetches any x402-protected URL unpaid and decodes its 402 payment quote to expose pricing, network, asset, and risk signals before an agent commits funds
Price / call$0.002
Success—
StatusUnknown
How this service works
Pay-per-call crypto microdata for trading/onchain AI agents via x402 (USDC on Base): Base gas, token risk, balances, multi-venue prices, Hyperliquid book/funding, kimchi premium. No API keys.
Output
A JSON object containing: a human-readable verdict (e.g. SAFE_TO_PAY), a boolean should_pay, a numeric risk_score (0–1), the cheapest payment option (price_usd, asset_label, network_name, payTo, scheme, is_usdc, max_timeout_s), whether the endpoint is within the requested budget, x402 protocol version, whether a Bazaar discovery schema is present, the resource URL and description, reachability status, latency_ms, TLS info, HTTP status, and a list of reasons and flags explaining the assessment.
Example use cases
Budget guard before paying an unknown API
“I found a new x402 API at https://api.example.com/data/prices — before my agent pays anything, can you check it, tell me the USD price per call, confirm it's USDC on Base, and flag any risks? My budget is $0.01 per call.”
Verify payTo address before onchain transfer
“Check the x402 quote on https://some-defi-agent.io/v1/signal — I want to see the payTo address, whether it's a contract or EOA, and whether the asset is canonical USDC before I approve the payment.”
Confirm Bazaar-listed endpoint before agent workflow
“My agent is about to call an x402 endpoint at https://marketplace.bazaar.ai/feeds/gas — can you verify it returns a Bazaar discovery schema, the version is x402 v2, and the latency is reasonable before we wire it into our pipeline?”
Technical details
Endpoint
GEThttps://kr-x402-mvp.kgy5612.workers.dev/crypto/x402-check?utm_source=zero.xyzWhen to prefer
Use this endpoint whenever an AI agent needs to pre-flight an x402-protected API before committing USDC — especially useful for budget enforcement (max_usd), asset/network validation (confirming canonical USDC on Base vs. other chains), risk scoring unknown payTo addresses, and confirming Bazaar schema compliance. Prefer this over blindly paying a 402 response when operating in automated pipelines where unexpected charges or malicious payTo addresses are a concern.
Side effects
- Target URL is unreachable — reachable: false, no options decoded
- Target URL does not return a 402 — verdict may indicate non-x402 endpoint
- Malformed or missing PAYMENT-REQUIRED header — parse failure, empty options array
- TLS error on target — flagged in flags array
- Price exceeds max_usd — within_budget: false
- Non-canonical asset (not USDC) — is_usdc: false flagged in cheapest_option
- x402 version mismatch or unsupported scheme — flagged in reasons
- Self-test fallback used when url param is omitted
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://kr-x402-mvp.kgy5612.workers.dev/crypto/ping",
"flags": [],
"options": [],
"reasons": [
"402 quote parsed: 1 option(s)",
"cheapest $0.001 USDC on base"
],
"verdict": "SAFE_TO_PAY",
"resource": {
"url": "https://kr-x402-mvp.kgy5612.workers.dev/crypto/ping",
"host_match": true,
"description": "Paid heartbeat"
},
"reachable": true,
"checked_at": "2026-10-30T07:30:00Z",
"latency_ms": 180,
"risk_score": 0,
"should_pay": true,
"http_status": 402,
"x402_version": 2,
"bazaar_schema": true,
"payto_onchain": {
"chain": "base",
"is_contract": false,
"usdc_balance": 0.079
},
"within_budget": true,
"cheapest_option": {
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"payTo": "0xe4be4d0bd82d8e68203deff81f79ede0529f2617",
"scheme": "exact",
"is_usdc": true,
"network": "eip155:8453",
"price_usd": 0.001,
"asset_label": "USDC",
"network_name": "base",
"max_timeout_s": 300
}
}
}Tags
x402
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