# PreFlight Checker – Domain Liveness & DNS Audit

> PreFlight Checker – Domain Liveness & DNS Audit is a paid API for AI agents from x402-api-catalog.onrender.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Checks whether a domain is live by resolving its DNS records (A, MX, NS, TXT), verifying mail routing, and testing HTTP reachability.

## Facts

- Endpoint: GET https://x402-api-catalog.onrender.com/api/domain-check
- 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/preflight-checker-domain-liveness-dns-audit-b668c3eb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_001ZertLUYTa8LpG8Fzm3

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 preflight-checker-domain-liveness-dns-audit-b668c3eb
```

Example prompt: Can you run a full domain liveness check on acmecorp.io — I need to know if it resolves, whether its MX records are set up for mail, and if the site is actually reachable over HTTP?

## When to prefer this

Choose this endpoint when you need a quick, comprehensive liveness audit of a domain covering DNS (A/MX/NS/TXT), mail routing, and HTTP reachability in a single call. Prefer it over individual DNS lookup tools when you want a consolidated verdict rather than raw record data, or when evaluating domain health for email deliverability, vendor vetting, or domain acquisition research.

## Known failure modes

- Domain does not exist (NXDOMAIN) — returns negative verdict with no DNS records
- Domain resolves but HTTP endpoint is unreachable — partial result with DNS data but HTTP failure
- Invalid or malformed domain input — request rejected with validation error
- Upstream DNS resolver timeout — may return partial or empty results
- Rate limiting or payment failure — request not processed

## How this service works

Domain liveness check / verify / audit: DNS resolution (A/MX/NS/TXT records), whether mail routing exists, HTTP reachability.

## Output

Returns a verdict object with the domain name and liveness status, along with DNS resolution details (A, MX, NS, TXT records), mail routing existence, and HTTP reachability — summarized into an overall pass/fail verdict.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "description": "domain to check, e.g. example.com"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "domain": {
       "type": "string"
      },
      "verdict": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "domain": "example.com",
  "verdict": "fully live",
  "httpReachable": true,
  "hasMailRouting": true,
  "hasWebPresence": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/preflight-checker-domain-liveness-dns-audit-b668c3eb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-api-catalog.onrender.com](https://www.zero.xyz/host/x402-api-catalog.onrender.com/llms.txt)