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Free email deliverability checker for cold email

Type in a sending domain and this checks the DNS records inbox providers look at before they decide where your email lands: MX, SPF (including the 10 lookup limit), DMARC, DKIM, plus BIMI and MTA-STS. Then paste a draft to scan it for spam phrases, links, merge tags, and other things that hurt cold email placement. It runs in your browser, is free, and needs no signup.

Built by Garrett Wolfe, founder of OneGTM. We set up sending infrastructure for outbound teams. Updated .

Check every domain you send cold email from, not only your main one.

Key takeaways

  • Since 2024, Gmail and Yahoo require SPF or DKIM for all senders, and SPF, DKIM, and DMARC for anyone sending 5,000+ a day. Microsoft started enforcing the same for Outlook.com in May 2025.
  • An SPF record over 10 DNS lookups fails outright, even if every include looks right.
  • Never send cold email from your main domain. Use separate lookalike domains with 2 or 3 inboxes each.
  • Perfect DNS does not guarantee the inbox. Volume, warmup, list quality, and copy decide the rest.

What this email deliverability test checks

Mailbox providers decide a lot before anyone reads your email. The first thing they look at is whether the domain proves it is allowed to send, and whether it tells them what to do when a message fails that test. That lives in a handful of DNS records.

  • MX records. Whether the domain can receive mail. A domain that sends but cannot receive looks disposable, and your replies bounce.
  • SPF. The list of servers allowed to send for you. We check that there is exactly one record, that it ends in ~all or -all, and we walk every include to count DNS lookups against the limit of 10.
  • DMARC. Your policy for mail that fails SPF and DKIM (none, quarantine, or reject), plus whether you get reports.
  • DKIM. The cryptographic signature on each message. We probe 18 common selectors (Google, Microsoft, Zoho, Mailchimp, and others) and flag 1024-bit and revoked keys.
  • BIMI, MTA-STS, and TLS-RPT. Optional extras. Good on your brand domain, low priority on cold sending domains.

How to set up cold email deliverability in 2026

Most of the deliverability problems I get asked about are not DNS problems. The records pass, and the emails still go to spam because of how the sending is set up. This is the setup we use for clients running outbound:

  • Keep cold email off your main domain. Buy a few lookalike domains (getacme.com, tryacme.com) and redirect them to your site. If one burns, your company email keeps working.
  • Use 2 or 3 inboxes per domain, on Google Workspace or Microsoft 365, each with SPF, DKIM, and DMARC set up before the first send.
  • Warm up new inboxes for two to three weeks before any cold volume, and keep warmup running at a low level after.
  • Cap volume around 30 cold emails per inbox per day. Scale by adding inboxes, not by pushing each one harder.
  • Verify every address and keep bounces under 2%. Catch-all domains need a second check.
  • Write plain text. No images, no tracking pixels on new domains, and no links in the first email if you can help it.
  • Watch spam complaints. Google wants you under 0.3%, and ideally under 0.1%. Google Postmaster Tools shows you where you stand.

If you would rather have this built for you, our outbound agency work starts with the sending setup: domains, inboxes, DNS, warmup, and a sequencer like Instantly or Smartlead wired to your CRM.

What this checker cannot see

DNS is only the entry ticket. This page does not check blacklists, IP or domain reputation, or where a real email actually lands. For those, look up your domain on MXToolbox, connect it to Google Postmaster Tools and Microsoft SNDS, and send a seed test to a set of Gmail and Outlook inboxes before a big launch. DKIM is also only detectable when we can guess the selector, so if you use a custom one, check a sent email's headers for s= to confirm it.

Email deliverability FAQ

How do I test my email deliverability?
Start with DNS: check that your sending domain has one valid SPF record under 10 lookups, a DKIM key, and a DMARC policy. This page does that for free. Then check blacklists on MXToolbox, connect Google Postmaster Tools, and send a seed test to Gmail and Outlook inboxes to see where real messages land.
What is a good email deliverability score?
On this checker, 90 or above means your DNS setup is solid. 70 to 89 usually means DMARC is still at p=none or DKIM uses an older 1024-bit key. Under 70 means something required is missing, and Gmail or Outlook are likely filtering you.
Do I need SPF, DKIM, and DMARC for cold email?
Yes. Since February 2024, Gmail and Yahoo require SPF or DKIM for every sender and all three for anyone sending 5,000 or more emails a day. Microsoft began enforcing similar rules for Outlook.com in May 2025. Cold email without them mostly goes to spam.
What is the SPF 10 lookup limit?
SPF allows at most 10 DNS lookups while checking a record, counting every include, a, mx, ptr, exists, and redirect, including the ones inside other includes. Go over 10 and receivers return a permanent error, so SPF fails even though the record looks fine. Removing old tools or moving senders to subdomains fixes it.
Why can't the checker find my DKIM record?
DKIM keys sit at a selector name chosen by your email provider, and there is no way to list them. We test 18 common selectors. If yours is custom, open a sent email, view the original, and find s= in the DKIM-Signature header to see the selector you use.
Should I send cold email from my main domain?
No. Send cold email from separate lookalike domains, each with 2 or 3 warmed inboxes. If one gets flagged, your main domain, where your team and customers email, is not affected.
How many cold emails can I send per inbox per day?
Around 30 per inbox per day is a safe ceiling for most teams, after two to three weeks of warmup. To send more, add inboxes and domains instead of raising the volume on each one.
Is this email deliverability checker free?
Yes. It is free with no signup. The DNS lookups run from your browser through public DNS-over-HTTPS resolvers, and the copy check runs on the page, so nothing you paste is stored.

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