# Domain Preflight Check API

> Domain Preflight Check API is a paid API for AI agents from x402-canary.nicolas-x402-16f380a7.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-16).

Checks whether a given domain has MX and DNS records configured, returning a preflight readiness summary for coding agent workflows.

## Facts

- Endpoint: POST https://x402-canary.nicolas-x402-16f380a7.workers.dev/v1/domain/preflight
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/domain-preflight-check-api-6ae586dc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CoozuPfe9KJwCQy8hcT8C

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 domain-preflight-check-api-6ae586dc -d '<json body>'
```

Example prompt: Can you run a preflight check on example.com to see if it has MX and DNS records configured?

## When to prefer this

Use this endpoint when you need a quick, cheap ($0.02 USDC) binary check on whether a domain has MX and/or DNS records active — ideal for pre-validating email targets, filtering lead lists, or gating agent workflows on domain readiness before attempting communication. Prefer this over full DNS lookup services when you only need a simple yes/no preflight signal rather than detailed record contents.

## Known failure modes

- Invalid or malformed domain string returns an error response
- Non-existent TLD may return false for both has_mx and has_dns
- Network timeout if DNS resolution is slow
- Missing `domain` field in request body may cause a 400 error
- Payment failure via x402 protocol blocks the call

## How this service works

Free need-to-tool routing plus pay-per-call npm docs and TypeScript API signatures, npm breaking-change diffs, JavaScript-rendered browser snapshots and deterministic coding-agent checks via AgentCash/x402.

## Output

Returns a JSON object with a `data` field containing `has_mx` (boolean indicating MX record presence) and `has_dns` (boolean indicating DNS record presence), plus a `meta` field with an `engine` key set to 'preflight'.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "domain": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "has_mx": true,
   "has_dns": true
  },
  "meta": {
   "engine": "preflight"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/domain-preflight-check-api-6ae586dc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-canary.nicolas-x402-16f380a7.workers.dev](https://www.zero.xyz/host/x402-canary.nicolas-x402-16f380a7.workers.dev/llms.txt)