# x402 Preflight Check

> x402 Preflight Check is a paid API for AI agents from agentdata-api.sander-van-aard.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Probes a target x402 resource URL live and returns its current status, latency, 402 validity, and 30-day monitoring history before you pay

## Facts

- Endpoint: POST https://agentdata-api.sander-van-aard.workers.dev/x402/preflight
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-preflight-check-312cca6d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8yExC9QlJPBfYreMMxNHQ

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-check-312cca6d -d '<json body>'
```

Example prompt: Before I pay for that x402 API at https://api.example.com/data, can you do a preflight check — probe it live right now and pull its 30-day uptime history, and confirm the payTo address actually matches 0xAbC123...?

## When to prefer this

Use this endpoint when you are about to pay an x402 service and want to confirm it is live, correctly configured, and has a reliable uptime history before committing funds. Especially valuable when paying an unfamiliar endpoint, when you want to detect price or payTo drift, or when you need to programmatically gate payment on service health.

## Known failure modes

- Target URL is unreachable — returns probe failure with connection error details
- Target URL does not return a 402 response — flagged as not a valid x402 service
- pay_to mismatch — live 402 payTo does not match the provided expected address
- No monitoring history available for this host — history section returns empty or null
- Malformed request body — missing required fields returns validation error
- Target service times out — latency recorded, status flagged as timeout

## How this service works

Preflight before paying an x402 service: is it working right now, and did it work the past 30 days? One live probe of the exact resource URL you intend to pay (status, latency, x402 validity, the payTo/price the service itself publishes in its 402, manifest presence) plus our own monitoring history of the host (30-day uptime, last check, recent changes such as payTo or price drift). Optionally verifies that the pay_to you intend to pay matches the live 402. Facts only — no scores.

## Output

Returns live probe results for the target URL (HTTP status, latency, whether the 402 response is valid, the payTo address and price the service currently publishes, and whether a manifest is present), plus 30-day monitoring history (uptime percentage, last check timestamp, and any recent changes to payTo address or price).

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-preflight-check-312cca6d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentdata-api.sander-van-aard.workers.dev](https://www.zero.xyz/host/agentdata-api.sander-van-aard.workers.dev/llms.txt)