# Lookproof MX Record Lookup

> Lookproof MX Record Lookup is a paid API for AI agents from api.lookproof.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-31).

Lists a domain's mail servers in priority order and detects null MX (RFC 7505) or unresolvable MX targets, with coded diagnostic findings.

## Facts

- Endpoint: GET https://api.lookproof.dev/v1/mail/mx?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/lookproof-mx-record-lookup-45ea99ba
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NU-iUNE941nRMLkvbS4Va

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 lookproof-mx-record-lookup-45ea99ba
```

Example prompt: Can you look up the mail servers for acme.com, list them in preference order, and tell me if the domain is configured to reject email or if any of the MX targets don't resolve?

## When to prefer this

Use this endpoint when you specifically need to understand mail routing for a domain — either to enumerate MX servers in priority order, detect a null MX (RFC 7505) indicating the domain intentionally rejects mail, or diagnose why a domain cannot receive email. Prefer this over a generic DNS resolver endpoint when you need structured mail-routing semantics, coded diagnostic findings, and RFC 7505 null MX detection rather than raw DNS record data.

## Known failure modes

- Domain does not exist (NXDOMAIN) — returns no MX records with a not-found diagnostic code
- Domain has no MX records — returns empty list with a coded finding indicating no mail routing configured
- MX targets exist but do not resolve to any IP — flagged per-target with a resolution-failure code
- Malformed or excessively long domain input — rejected with a validation error
- DNS resolver timeout — may return partial results or a timeout error code

## How this service works

Check SPF, DMARC, DKIM, MTA-STS, DNSSEC and more, with results that explain what was found and why. Free browser checks and a pay-per-request API with x402.

## Output

Returns an ordered list of MX records for the domain (hostname and preference value for each), a flag indicating whether a null MX (RFC 7505) is present, the resolution status of each MX target hostname, and coded findings describing any detected issues such as unresolvable targets or missing MX records.

## 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",
     "title": "DomainInput",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "title": "Domain",
       "examples": [
        "example.com"
       ],
       "maxLength": 1024,
       "minLength": 1
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lookproof-mx-record-lookup-45ea99ba/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.lookproof.dev](https://www.zero.xyz/host/api.lookproof.dev/llms.txt)