Free tool
Deep email check
Is this address likely real? We check its format, the provider's username rules, throwaway and role addresses, and the domain's mail records: MX, SPF, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI.
| Check | Result | Details |
|---|
Use it from your code
The same check is a free API: no key, no sign-up. 100 checks a day per IP, or 1,000 a day per account when you send your email59 key.
curl -s 'https://email59.com/v1/check?email=sam@example.com'The reply has a score (0 to 99), a verdict (likely_valid, risky, likely_invalid or unknown), a summary and one entry per check in checks. Bots can call the check_email tool on the MCP server without signing in. Details in the docs.
What the checks mean
| Check | What it tells you |
|---|---|
| MX | The domain's mail servers. No MX, a null MX or a missing domain means no mailbox can exist. |
| SPF | Which servers may send mail for the domain. A sign of a domain that is looked after. |
| DMARC | What receivers should do with mail that fails SPF or DKIM: none, quarantine or reject. |
| DKIM | Signing keys for the domain's mail. We try common selectors; others can't be listed. |
| MTA-STS, TLS-RPT, BIMI | Optional extras: forced TLS, TLS reports and a brand logo in inboxes. |
The score is an estimate. A domain with good records can still lack this one mailbox, and some servers accept every address. Only a delivered email proves an address.
Send to addresses you checked
email59 is an email router with a small API for OTP codes, newsletters and alerts. No subscriptions.