# ProbeKit Mail Authentication Check

> ProbeKit Mail Authentication Check is a paid API for AI agents from api.probekit.dev, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-30).

Returns a single consolidated report of a domain's email authentication setup — MX, SPF, DMARC, and optional DKIM selectors — with coded findings and an overall status.

## Facts

- Endpoint: GET https://api.probekit.dev/v1/mail/check?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/probekit-mail-authentication-check-ac7f3977
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nwxpsSWvtq74Mout34iG_

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 probekit-mail-authentication-check-ac7f3977
```

Example prompt: Can you run a full email authentication check on acme.com — including SPF, DMARC, MX, and DKIM for selectors 'google' and 'selector1' — and give me a summary of what's properly configured and what's broken?

## When to prefer this

Choose this endpoint when you need a comprehensive, single-call overview of a domain's full email authentication posture (MX + SPF + DMARC + DKIM together). Prefer it over individual record endpoints when you want a unified status verdict and coded findings without stitching together four separate API calls. If you only need one record type (e.g. just DMARC or just SPF), the sibling single-record endpoints are cheaper and more targeted.

## Known failure modes

- Domain not found or nonexistent — returns an error or empty results for DNS lookups
- Invalid domain format — API returns a validation error
- DKIM selectors not found — individual DKIM lookups return not-found status rather than a record
- Rate limiting or payment failure — 402 or 429 response if the x402 payment is not processed
- Timeout on DNS resolution — may occur for slow or unresponsive authoritative nameservers
- Too many DKIM selectors provided — schema enforces a maximum of 5 selectors

## How this service works

One report on a domain's mail setup: MX, SPF and DMARC, plus DKIM for the selectors you give, with coded findings and an overall status. Use when an agent needs a complete overview of a domain's email authentication and delivery configuration in one call instead of four.

## Output

A structured report covering: MX records and priority order, parsed SPF record with evaluation findings, DMARC policy and tags, DKIM public key results for each requested selector, coded diagnostic findings per record type, and an aggregated overall email authentication status (e.g. pass, partial, fail).

## 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": "MailCheckInput",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "title": "Domain",
       "examples": [
        "example.com"
       ],
       "maxLength": 1024,
       "minLength": 1
      },
      "dkim_selectors": {
       "type": "array",
       "items": {
        "type": "string",
        "examples": [
         "selector1"
        ],
        "maxLength": 200,
        "minLength": 1
       },
       "title": "Dkim Selectors",
       "default": [],
       "maxItems": 5
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/probekit-mail-authentication-check-ac7f3977/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.probekit.dev](https://www.zero.xyz/host/api.probekit.dev/llms.txt)