# DMARC + SPF + DKIM Email Authentication Checker

> DMARC + SPF + DKIM Email Authentication Checker is a paid API for AI agents from x402-deployer.x402-deployer.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Audits a domain's email authentication posture by reading its DNS TXT records for SPF, DMARC, and DKIM, then returns a 0-100 score, A-F grade, and human-readable findings explaining spoofing resistance and deliverability readiness.

## Facts

- Endpoint: POST https://x402-deployer.x402-deployer.workers.dev/dmarc-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/x402-deployer-x402-deployer-workers-dev-6d6f650c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y3tT6Mf4OH8mB-FwXfC7U

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 x402-deployer-x402-deployer-workers-dev-6d6f650c -d '<json body>'
```

Example prompt: Can you do a full DMARC, SPF, and DKIM audit on acme.com and tell me the overall score, grade, and any issues with my email authentication setup that could let spoofed emails through?

## When to prefer this

Use this endpoint when you need a structured, scored audit of a domain's complete email authentication posture (SPF + DMARC + DKIM together) with per-finding explanations and a normalized grade — rather than a raw DNS lookup tool that just returns record text without parsing or scoring.

## Known failure modes

- Domain has no SPF or DMARC record — returned with zero score and findings noting missing records
- Invalid or malformed SPF/DMARC syntax — parser returns error details for the offending record
- Domain does not exist or DNS lookup fails — returns DNS resolution error
- DKIM selectors not discoverable — DKIM portion of report may be incomplete or skipped
- Rate limiting or upstream DNS timeouts — request may fail with a 429 or 5xx response

## How this service works

DMARC + SPF + DKIM email-authentication checker / mail-auth posture audit / spoofing-resistance grader / phishing-readiness scanner / domain email security score / dmarcian-style report / pre-send deliverability check. Reads the domain's DNS TXT records, parses each protocol's record (SPF mechanisms + qualifiers, DMARC tags p/sp/rua/ruf/pct/aspf/adkim, DKIM selectors with key bits and algorithm), and returns a 0-100 score, A-F grade, and per-finding human-readable reasons explaining the score.

## Output

Returns a 0-100 numeric score, an A-F letter grade, parsed SPF mechanisms and qualifiers, all DMARC tag values (p, sp, rua, ruf, pct, aspf, adkim), DKIM selector details including key size in bits and algorithm, plus a list of human-readable findings explaining exactly what is configured correctly or incorrectly and why points were deducted.

## Example request

```json
{
 "domain": "example.com"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-6d6f650c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-deployer.x402-deployer.workers.dev](https://www.zero.xyz/host/x402-deployer.x402-deployer.workers.dev/llms.txt)