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Email Intelligence

Validate email addresses

Multi-step validation via syntax, DNS/MX check, disposable detection, role mailbox detection and optional SMTP probe. GDPR-compliant — no raw data stored.

Get started for freePOST /v1/email/validate · 6 credits/request

A syntactically valid email address isn't necessarily a deliverable one. Email Intelligence runs a full validation pipeline — syntax, DNS/MX resolution, disposable and free-mail detection, role-mailbox detection, and an optional live SMTP probe — and returns a single actionable status instead of a raw pass/fail, so you can allow, warn on, or block an address based on your own policy.

Where Email Intelligence fits in your workflow

Signup form validation

Catch typos, disposable addresses and undeliverable domains at signup, before a bad address ever enters your CRM or mailing list.

List hygiene before a campaign

Run an existing list through bulk validation before sending, reducing bounce rate and protecting your sender reputation with the receiving mail providers.

Disposable and role-mailbox filtering

Flag mailinator-style disposable addresses and generic role mailboxes (info@, support@) separately from genuinely risky-but-real personal addresses, so your policy can treat them differently.

Bulk CSV cleanup

Upload a CSV of up to 500,000 addresses via the async job endpoint and get a per-row status back — the same workflow used internally to benchmark against Bouncer in this exact system.

Example request

curl -X POST https://api.toolbox-api.net/v1/email/validate \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email": "info@mailinator.com"}'
{
  "email": "info@mailinator.com",
  "status": "risky",
  "reason": "disposable_email",
  "syntaxValid": true,
  "mxFound": true
}

How it works

Each address goes through syntax validation, DNS/MX resolution, disposable/free-mail/role-mailbox detection against maintained lists, and — where enabled — a real SMTP handshake against the mail server to check deliverability, including catch-all domain detection so a single "accepts everything" mailbox doesn't produce a false positive. No raw email content is ever stored; only the validation result and reason are returned.

  • ✓Syntax + DNS/MX check
  • ✓Disposable & freemail detection
  • ✓Policy-configurable (allow/warn/block)
  • ✓Batch up to 100 (sync) / 500,000 (async)
  • ✓Batch up to 100 (sync) / 500,000 (async)

Email Intelligence — frequently asked questions

Do you actually connect to the target mail server?
Yes, when the SMTP probe step is enabled — a real SMTP handshake is opened to check deliverability. This step is skipped automatically once a domain is known to be a catch-all, to avoid an unnecessary connection.
How do you handle catch-all domains?
A catch-all domain (one that accepts mail to any address) is detected and cached per domain, so validation for that domain returns an "accepted" status without probing each individual address the same way.
Can I validate a whole CSV list at once?
Yes — upload a CSV via the async bulk endpoint (up to 500,000 rows), poll the job status, and download per-row results including status and reason once complete.

Ready to try it?

One API key gets you this and four other APIs, sharing one quota.

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