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Email deliverability checker

Enter a domain to check the DNS records mailbox providers look at before they decide where your email goes: MX, SPF, DKIM, DMARC, BIMI and MTA-STS.

Runs in your browser. The domain you enter is only sent to Cloudflare's public DNS resolver (cloudflare-dns.com) for the lookups; we don't store it. Like the rest of this site, the page uses Google Analytics to count visits. We don't store or receive the domain you check, and this page has no tracking.

What Gmail, Yahoo and Outlook require of bulk senders

Read from each provider's official pages on 11 October 2026.

Gmail

  • Applies at close to 5,000 messages a day to personal Gmail accounts. Once you're classed as a bulk sender, the status doesn't expire.
  • SPF and DKIM, plus DMARC (p=none is allowed), with the From: domain aligned to SPF or DKIM.
  • One-click unsubscribe (RFC 8058) on marketing mail, honored within 48 hours.
  • Spam rate below 0.1%, and never 0.3% or higher.
  • From November 2025, Gmail says non-compliant mail faces temporary and permanent rejections.

Sources: Email sender guidelines, Sender guidelines FAQ

Yahoo

  • No published volume threshold for "bulk".
  • SPF and DKIM, plus DMARC of at least p=none that passes, with From: domain alignment.
  • One-click unsubscribe (RFC 8058), honored within 2 days, plus a visible unsubscribe link.
  • Spam rate below 0.3%.

Sources: Sender best practices, Sender FAQ

Outlook.com, Hotmail and Live

  • Applies to domains sending over 5,000 emails a day to Microsoft consumer mailboxes.
  • SPF must pass, DKIM must pass, and DMARC of at least p=none must align with SPF or DKIM.
  • From 5 May 2025, non-compliant mail is rejected with "550 5.7.515 Access denied".
  • Microsoft also recommends a working unsubscribe link, a From or Reply-To address that receives replies, and regular list cleaning.

Sources: Microsoft announcement, 550 5.7.515 help page

What this checker looks at

  • MX: whether the domain can receive mail, which matters for replies and bounces.
  • SPF: one record only, a closing ~all or -all, no +all, and a count of DNS lookups against the limit of 10. The checker follows each include: to count them.
  • DKIM: a public key on common selectors (google, selector1, selector2, k1, s1, s2, default, mandrill, mailjet, zoho, amazonses). Many senders use custom selectors, so "not found" here doesn't mean DKIM is missing.
  • DMARC: whether a record exists, its policy (none, quarantine or reject) and whether it asks for aggregate reports (rua).
  • BIMI and MTA-STS: optional extras. BIMI can show your logo in some inboxes once DMARC is enforced. MTA-STS tells other servers to use encrypted connections when they deliver to you.

What it can't tell you

DNS records are only the first part of deliverability. This page can't see your sending reputation, spam complaint rate, blocklist status, inbox placement or message content. Google Postmaster Tools and Microsoft SNDS are free and show some of that for your own domains and IPs.

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