Email verification API: syntax, MX and disposable checks

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Check email syntax, DNS and MX records, disposable providers, role addresses, free providers and SPF/DMARC presence. Returns likely-deliverable, risky, undeliverable or invalid with reasons. No message is sent and the mail server is not contacted. These are DNS and syntax signals, not proof that a mailbox exists or accepts delivery. Use before sending mail or saving a signup.

When to use it

Check an address before sending mail or saving a signup
Flag disposable, role and free-provider addresses
See whether the domain has MX records and SPF/DMARC

Guide: Email verification API

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Inputs

Name	Type	Description
`address` (required)	string	The email address to check

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/email?address=support%40cloudflare.com"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/email?address=support%40cloudflare.com&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "address": "support@cloudflare.com",
  "validSyntax": true,
  "domain": "cloudflare.com",
  "domainExists": true,
  "acceptsMail": true,
  "disposable": false,
  "roleAddress": true,
  "freeProvider": false,
  "hasSpf": true,
  "hasDmarc": true,
  "verdict": "likely-deliverable",
  "reasons": [
    "role address, not a person"
  ]
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is email, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Does it send an email?

No. No message is sent and the mail server is not contacted; the result comes from syntax and DNS signals.

Does it prove the mailbox exists?

No. It returns likely-deliverable, risky, undeliverable or invalid with reasons, which are signals, not proof of delivery.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.