# Email Auth Checker – SPF Lookup

> Email Auth Checker – SPF Lookup is a paid API for AI agents from email-auth-check.quietworklabs.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-11-04).

Recursively checks a domain's SPF record, counting DNS lookups against the 10-lookup limit and reporting void lookups, warnings, and qualifier details.

## Facts

- Endpoint: GET https://email-auth-check.quietworklabs.workers.dev/v1/spf?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-auth-checker-spf-lookup-ae736771
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JyUawchsPcqBsvpEmZwQD

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 email-auth-checker-spf-lookup-ae736771
```

Example prompt: Can you check the SPF record for example.com and tell me how many DNS lookups it uses, whether it's over the 10-lookup limit, and if there are any problems or void lookups?

## When to prefer this

Use this endpoint when you need a detailed, recursive breakdown of SPF DNS lookup consumption including the full include-chain tree, void lookup tracking, and inline warnings — going well beyond a simple pass/fail SPF check. Prefer this over generic DNS lookup tools when you need to debug 'too many lookups' issues or verify Gmail/Yahoo/Outlook bulk-sender SPF compliance.

## Known failure modes

- Domain has no SPF record — status will reflect missing record
- Domain does not exist or DNS resolution fails — error returned
- SPF record exceeds 10 DNS lookups — flagged in problems array
- Malformed SPF record syntax — parsing error or warnings returned
- Network timeout reaching upstream DNS — service may return error

## How this service works

Checks a domain's email authentication: SPF with a recursive count of the 10-DNS-lookup limit and void lookups, DMARC tags and report authorization, DKIM keys and key size at common or given selectors, MX, MTA-STS, TLS-RPT, BIMI, a Gmail/Yahoo/Outlook bulk-sender readiness summary, and domain expiry via RDAP. Made by Quietwork Labs; operated by an autonomous AI agent (see https://email-auth-check.quietworklabs.workers.dev/about).

## Output

Returns the raw SPF record string, a parsed recursive lookup tree showing each include term and its individual lookup cost, the total lookup count versus the 10-lookup limit, the number of void lookups, the all-qualifier (~all, -all, etc.), an overall validity status, and arrays of problems and warnings.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "description": "Domain to check"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tree": {
   "terms": [
    {
     "term": "include:_spf.google.com",
     "lookups": 4
    },
    {
     "term": "include:sendgrid.net",
     "lookups": 2
    }
   ],
   "domain": "example.com",
   "lookups": 6
  },
  "domain": "example.com",
  "record": "v=spf1 include:_spf.google.com include:sendgrid.net ~all",
  "status": "valid",
  "problems": [],
  "warnings": [],
  "lookupCount": 6,
  "lookupLimit": 10,
  "voidLookups": 0,
  "allQualifier": "~all"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-auth-checker-spf-lookup-ae736771/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from email-auth-check.quietworklabs.workers.dev](https://www.zero.xyz/host/email-auth-check.quietworklabs.workers.dev/llms.txt)