Email pre-check

GET /api/verify-email · $0.003 per call (USDC on Base or Solana, x402)

Verify and validate an email address before sending: syntax, MX records, disposable domain, free webmail, role account. Email verification from DNS only: input an email, output a 0-100 deliverability score with its reasons, mail provider (Google, Microsoft 365, OVH...), SPF, DMARC, null MX and random-looking local part. Mailbox not tested (no SMTP: smtp_check:false, accept_all:null), so the score is capped at 90.

Problem solved

You want to pre-check an email address (syntax, MX, provider, disposable, webmail, role account) before sending.

Use cases

Drop obviously bad addresses (no MX, disposable, random-looking) from a list before a send.
Check the domain of a probable email returned by decision makers: MX present, provider, SPF and DMARC.

Input

GET /api/verify-email?email=<address>

Parameter	Where	Type	Description
`email` (required)	query	string	Email address to check

Output

Pre-check with score 0-100 and reasons [{code, points, detail}] from DNS only: syntax, MX, null MX, provider, SPF, DMARC, disposable, free webmail, role account, random-looking local part. Capped at 90: the mailbox is not tested (mailbox_checked:false, smtp_check:false, accept_all:null).

Price

$0.003 per call. Charged on every valid call (a missing email parameter is a 400, not charged).

Example

GET https://resolve402.dev/api/verify-email?email=jane%40acme.fr

{
  "email": "jane@acme.fr",
  "syntax_valid": true,
  "has_mx": true,
  "mail_provider": "google_workspace",
  "deliverable": "likely",
  "score": 90,
  "score_band": "good",
  "reasons": [
    {
      "code": "mx_present",
      "points": 30,
      "detail": "Domain has 2 MX record(s)."
    }
  ],
  "accept_all": null,
  "smtp_check": false,
  "mailbox_checked": false
}

Bazaar discovery example served in the production 402 (abridged).

Sources

DNS records of the domain (MX, A, SPF, DMARC)
Built-in lists of disposable and free webmail domains

Limits

No SMTP connection: the mailbox itself is not tested, so accept_all is unknown (null) and the score is capped at 90.
Disposable detection uses a short built-in list of common throwaway domains.

Use it

HTTP + x402: call the URL, pay the 402 with any x402 v2 client, retry with the PAYMENT-SIGNATURE header.
OpenAPI: /openapi.json (operation verifyEmail )
MCP: npx -y resolve402-mcp, tool verify_email (npm)
Agent guide: /llms.txt · skill: /SKILL.md

All services