Email deliverability audit for any domain. SPF, DKIM, DMARC, MX validation with score 0-100 and fix recommendations. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

json

{
  "mcpServers": {
    "email-deliverability": {
      "url": "https://email-deliverability.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

bash

curl "https://email-deliverability.api.klymax402.com/api/audit?domain=..."
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

Tool	Method	Path	Price	Description
`email_audit_deliverability`	GET	`/api/audit`	$0.012	Audit email deliverability for a domain — checks SPF, DKIM, DMARC, MX records
`email_audit_deliverability`	POST	`/api/audit`	$0.012	Audit email deliverability for a domain — checks SPF, DKIM, DMARC, MX records (POST variant)

`email_audit_deliverability`

Use this when you need to audit email deliverability configuration for a domain. Returns structured JSON with authentication record analysis and a deliverability score 0-100.

Parameters

Name	Type	Required	Description
`domain`	string	yes	Domain to audit (e.g. example.com, gmail.com)

Example response:

json

{"score":65,"spf":{"found":true,"valid":true,"record":"v=spf1 include:_spf.google.com ~all"},"dkim":{"google":true,"default":false},"dmarc":{"found":true,"policy":"none","record":"v=DMARC1; p=none"},"mx":[{"priority":10,"exchange":"alt1.gmail-smtp-in.l.google.com"}],"recommendations":["Upgrade DMARC policy from none to quarantine","Add DKIM for default selector"]}

When to use: launching email campaigns, onboarding new domains for outreach, or diagnosing inbox placement issues. Essential for email marketers, sales teams, and IT admins managing domain reputation.

Not for: single email validation (use email_verify_address), finding email addresses (use email_find_by_name), domain WHOIS/DNS (use domain_lookup_intelligence).

`email_audit_deliverability`

Use this when you need to audit email deliverability configuration for a domain. Returns structured JSON with authentication record analysis and a deliverability score 0-100. POST variant of email_audit_deliverability -- same params passed as JSON body instead of query string.

Parameters

Name	Type	Required	Description
`domain`	string	yes	Domain to audit (e.g. example.com, gmail.com)

Example response:

json

{"score":65,"spf":{"found":true,"valid":true,"record":"v=spf1 include:_spf.google.com ~all"},"dkim":{"google":true,"default":false},"dmarc":{"found":true,"policy":"none","record":"v=DMARC1; p=none"},"mx":[{"priority":10,"exchange":"alt1.gmail-smtp-in.l.google.com"}],"recommendations":["Upgrade DMARC policy from none to quarantine","Add DKIM for default selector"]}

Not for: single email validation (use email_verify_address), finding email addresses (use email_find_by_name), domain WHOIS/DNS (use domain_lookup_intelligence).

Example agent prompts

"Audit email deliverability configuration for a domain"
"Audit email deliverability configuration for a domain"

Payment

Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
Network: Base L2 (eip155:8453)
Asset: USDC
Facilitator: Coinbase CDP (primary), PayAI (fallback)
Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)