# x402 Endpoint Diligence Checker

> 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.

## Facts

- Endpoint: POST https://diligence.x402supply.com/tools/check_endpoint?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-endpoint-diligence-checker-f878c18f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1BTNWwB5-0FDbN91Onseo

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-endpoint-diligence-checker-f878c18f -d '<json body>'
```

Example prompt: Before I pay anything, run diligence on this x402 endpoint — https://api.someservice.com/data — and tell me its trust score, whether it passes, and if the price looks fair compared to market baselines.

## When to prefer this

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.

## Known failure modes

- 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

## 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.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "format": "uri"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "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
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-endpoint-diligence-checker-f878c18f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from diligence.x402supply.com](https://www.zero.xyz/host/diligence.x402supply.com/llms.txt)