# x402 Preflight

> x402 Preflight is a paid API for AI agents from 76.13.79.47.nip.io, paid per call via x402, $0.001/call, status down (last checked 2026-10-13).

Probes a paid x402 URL and its discovery metadata endpoints to return payment challenge signals, pricing context, discovery health, and conversion-readiness verdict without making any payment.

## Facts

- Endpoint: GET https://76.13.79.47.nip.io/token-signal-x402/v1/x402-preflight?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-preflight-f19bb8f6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WjhPcrwti5m9H0N_s5yV6

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-preflight-f19bb8f6
```

Example prompt: Can you run an x402 preflight check on https://api.example.com/paid-endpoint to see its payment challenge, pricing, discovery health, and whether it's ready for agent consumption — without actually paying?

## When to prefer this

Use this endpoint when you need to inspect and validate an x402 paid endpoint before integrating or paying — especially to assess payment challenge structure, pricing, and discovery metadata completeness. Prefer this over a raw HTTP request because it aggregates probes to multiple well-known paths, parses x402 payment metadata, benchmarks against Bazaar comparables, and returns a structured readiness verdict with actionable issues. Ideal for x402 sellers debugging their own endpoints and for buyers evaluating whether an endpoint is trustworthy before spending USDC.

## Known failure modes

- Target URL is unreachable or returns an unexpected non-402 status — probe may return incomplete signals
- Target URL is not an x402 endpoint — results will show low/zero payment challenge signals
- Well-known files (/.well-known/x402, /openapi.json, etc.) absent — discovery health score will be low
- Invalid or malformed URL input — returns validation error
- Target server rate-limits or blocks the probe — partial or empty results

## How this service works

x402 Preflight: HTTP readiness check for x402 API buyers, sellers, and listing agents. It probes a target paid URL plus same-origin /.well-known/x402 and /openapi.json, /llms.txt, /agent-catalog.json, and /.well-known/ai-plugin.json, then returns payment-challenge signals, parsed payment metadata, comparable Bazaar resources, pricing context, discovery health, LLM/catalog readiness, conversion-readiness verdict, score, issues, and next actions. No payment is made to the target endpoint.

## Output

Returns a structured object containing: the HTTP payment-challenge signals from the target URL (402 response headers), parsed x402 payment metadata, comparable Bazaar resources, pricing context, discovery health assessment, LLM and agent catalog readiness flags, a conversion-readiness verdict and numeric score, a list of issues found, and recommended next actions. No payment is made.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "Absolute public http(s) x402 endpoint URL to inspect"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-preflight-f19bb8f6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 76.13.79.47.nip.io](https://www.zero.xyz/host/76.13.79.47.nip.io/llms.txt)