x402 Endpoint Diligence Checker

x402

x402 Endpoint Diligence Checker is a paid API for AI agents from diligence.x402supply.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-12).

Runs live pre-payment diligence on an x402-metered API endpoint, verifying spec compliance, pricing fairness, on-chain payTo address integrity, directory presence, infra hygiene, and resale markup detection, returning a 0–100 trust score with pass/caution/fail verdict.

Price / call$0.02

Seller volume →—

Success—

StatusUnknown

How this service works

Runs live diligence on an x402-metered endpoint before you pay it: verifies its 402 payment challenge is spec-compliant, checks the price against market baselines, inspects the payTo address on-chain (Base), checks third-party directory presence, and checks basic infra hygiene. Returns a 0-100 score, a pass/caution/fail verdict, and per-check evidence.; Compares an x402 endpoint's price (or a given price/category pair) against market percentiles from our daily radar snapshot of the x402 ecosystem.

Output

Returns a structured result containing a 0–100 numeric trust score, an overall verdict of pass/caution/fail, and per-check evidence covering: 402 payment challenge spec compliance, price comparison against market baselines, on-chain verification of the payTo address on Base, third-party directory listing presence, basic infrastructure hygiene signals, and evidence-based markup estimates if upstream API resale is detected.

Example use cases

Pre-payment safety check for unknown API

“I found this x402-metered endpoint at https://inference.unknownprovider.io/complete — can you run diligence on it and tell me if it's safe to pay, what score it gets, and whether the payTo address checks out on Base?”

Detect resale markup on x402 wrapper

“This x402 endpoint at https://llm.thirdparty.xyz/v1/chat looks like it might just be wrapping OpenAI with a markup — can you check it for resale evidence and tell me how much above market it's pricing?”

Vet new x402 vendor before integrating

“We're about to integrate https://api.newvendor.com/weather into our agent pipeline — please run a full diligence check on it: 402 spec compliance, directory presence, infra hygiene, and overall verdict before we commit.”

Technical details

Endpoint

POSThttps://diligence.x402supply.com/tools/check_endpoint?utm_source=zero.xyz

When to prefer

Use this endpoint any time an AI agent or developer is about to make a payment to an unknown or untrusted x402-metered API and wants to verify it is safe, fairly priced, and spec-compliant before committing funds. Prefer this over manual inspection when you need on-chain address verification on Base, structured pricing comparison, or automated resale markup detection — tasks that are impractical to do by hand. It is especially valuable in autonomous agent workflows where a human is not reviewing each payment decision.

Side effects

Target endpoint is unreachable or returns no 402 challenge — diligence cannot be performed
Invalid or malformed URL input — returns validation error
Target endpoint's on-chain address is on an unsupported network (non-Base) — partial results
Rate limiting or network timeout when probing target endpoint — incomplete check
Target URL points to a non-x402 endpoint — returns spec compliance failure with explanation

Input

Schema · Request body

Field	Type	Description
url	string

Output

Schema · Response

{
  "type": "json",
  "example": {
    "url": "https://example.com/api/paid",
    "score": 29,
    "checks": [
      {
        "name": "spec_compliance",
        "result": "fail",
        "weight": 35,
        "evidence": "unexpected status 405 Method Not Allowed"
      },
      {
        "name": "price_sanity",
        "result": "unknown",
        "weight": 15,
        "evidence": "no challenge to price"
      },
      {
        "name": "payto_onchain",
        "result": "unknown",
        "weight": 25,
        "evidence": "no payTo address to check"
      },
      {
        "name": "directory_presence",
        "result": "caution",
        "weight": 15,
        "evidence": "origin not found on x402scan or in our market-baseline snapshot — no third-party discovery footprint"
      },
      {
        "name": "infra_hygiene",
        "result": "pass",
        "weight": 10,
        "evidence": "HTTPS enforced; domain registration age unavailable (RDAP lookup failed or unsupported TLD)"
      },
      {
        "name": "reseller_markup",
        "result": "pass",
        "weight": 0,
        "evidence": "no reseller signals"
      }
    ],
    "verdict": "fail",
    "resellerMarkup": {
      "verdict": "no reseller signals",
      "evidence": [
        "No upstream catalog entry reached the two-distinctive-signal threshold."
      ],
      "priceAsOf": null,
      "confidence": "none",
      "markupMultiple": null,
      "matchedUpstream": null,
      "upstreamPriceUsd": null
    }
  }
}

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How this service works

Output

Example use cases

Pre-payment safety check for unknown API

Detect resale markup on x402 wrapper

Vet new x402 vendor before integrating

Technical details

Endpoint

POSThttps://diligence.x402supply.com/tools/check_endpoint?utm_source=zero.xyz

When to prefer

Side effects

Target endpoint is unreachable or returns no 402 challenge — diligence cannot be performed
Invalid or malformed URL input — returns validation error
Target endpoint's on-chain address is on an unsupported network (non-Base) — partial results
Rate limiting or network timeout when probing target endpoint — incomplete check
Target URL points to a non-x402 endpoint — returns spec compliance failure with explanation

Input

Schema · Request body

Field	Type	Description
url	string

Output

Schema · Response

{
  "type": "json",
  "example": {
    "url": "https://example.com/api/paid",
    "score": 29,
    "checks": [
      {
        "name": "spec_compliance",
        "result": "fail",
        "weight": 35,
        "evidence": "unexpected status 405 Method Not Allowed"
      },
      {
        "name": "price_sanity",
        "result": "unknown",
        "weight": 15,
        "evidence": "no challenge to price"
      },
      {
        "name": "payto_onchain",
        "result": "unknown",
        "weight": 25,
        "evidence": "no payTo address to check"
      },
      {
        "name": "directory_presence",
        "result": "caution",
        "weight": 15,
        "evidence": "origin not found on x402scan or in our market-baseline snapshot — no third-party discovery footprint"
      },
      {
        "name": "infra_hygiene",
        "result": "pass",
        "weight": 10,
        "evidence": "HTTPS enforced; domain registration age unavailable (RDAP lookup failed or unsupported TLD)"
      },
      {
        "name": "reseller_markup",
        "result": "pass",
        "weight": 0,
        "evidence": "no reseller signals"
      }
    ],
    "verdict": "fail",
    "resellerMarkup": {
      "verdict": "no reseller signals",
      "evidence": [
        "No upstream catalog entry reached the two-distinctive-signal threshold."
      ],
      "priceAsOf": null,
      "confidence": "none",
      "markupMultiple": null,
      "matchedUpstream": null,
      "upstreamPriceUsd": null
    }
  }
}