# ContextIQ x402 Inspector — Payment Challenge Validator

> ContextIQ x402 Inspector — Payment Challenge Validator is a paid API for AI agents from contextiq.trango-compute.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Validates whether an HTTP 402 payment challenge (x402 protocol) is correctly formed, returning a structured scan result with status, warnings, and evidence.

## Facts

- Endpoint: POST https://contextiq.trango-compute.com/api/v1/x402-inspector/x402-v2
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/contextiq-x402-inspector-payment-challenge-validator-81946d14
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eNHrI_IW7rJbNUlOwCcvq

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 contextiq-x402-inspector-payment-challenge-validator-81946d14 -d '<json body>'
```

Example prompt: Check whether this x402 payment challenge is valid — status is 'invalid', target is 'https://api.example.com/data', the method used was HTTP 402, x402 version is x402-v2, and there are warnings about a missing accepts field. Give me the full inspection report.

## When to prefer this

Use this endpoint when you need to programmatically verify that an x402 payment challenge conforms to the x402-v2 protocol before committing a payment or integrating with a payment-gated API. It is especially valuable in agentic pipelines where an AI agent must autonomously decide whether a 402 response is trustworthy and safe to pay. Prefer this over manual inspection or generic HTTP debugging tools when you need structured, machine-readable validation output with explicit warnings and evidence.

## Known failure modes

- Missing or malformed input schema fields may result in a validation error response
- If the target is unreachable or no challenge is detected, status returns 'no_challenge'
- Unsupported x402 versions may produce incomplete scan results
- Payment failure ($0.02 USDC) if x402 payment header is not properly sent with the request

## How this service works

x402 Inspector scan (payment-challenge validation) — per call

## Output

A structured scan report indicating whether the x402 payment challenge is valid, invalid, malformed, or absent, along with details such as the HTTP method used, HTTP status code, x402 version, accepted payment methods, supporting evidence strings, any warnings about the challenge, and optionally the declared expected response shape from Bazaar discovery.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "status": {
   "type": "string",
   "description": "valid, invalid, malformed, or no_challenge"
  },
  "target": {
   "type": "string"
  },
  "details": {
   "type": "object",
   "description": "methodUsed, httpStatus, x402Version, accepts[]"
  },
  "evidence": {
   "type": "array",
   "items": {
    "type": "string"
   }
  },
  "warnings": {
   "type": "array",
   "items": {
    "type": "string"
   }
  },
  "expectedResult": {
   "type": "object",
   "description": "Declared response shape, if the seller published a Bazaar discovery extension"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/contextiq-x402-inspector-payment-challenge-validator-81946d14/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from contextiq.trango-compute.com](https://www.zero.xyz/host/contextiq.trango-compute.com/llms.txt)