SPF
Who can send email on your behalf?
It’s the guest list. It says which servers may send email with your domain; if one that isn’t on the list tries, the receiver gets suspicious.
SPF, DKIM and DMARC checker
Find out in seconds whether your emails meet the new Gmail, Yahoo and Outlook rules, or whether they are heading for spam.
How Gmail checks that an email is really yours
When you send an email, the receiving server runs three checks against your DNS before deciding whether to deliver it, send it to spam or reject it.
- Your server sends
- →
- Gmail, Outlook, Yahoo…SPFAuthorised server?DKIMSignature intact?DMARCWhat if it fails?
- →
- InboxSpamRejected
DKIM
Does the email arrive exactly as it left?
It’s the wax seal on the envelope. Every email leaves signed, and the receiver uses your public key to check nobody tampered with it on the way.
DMARC
What to do if something fails?
They are the doorman’s orders. You tell the receiver what to do with emails that pass neither SPF nor DKIM (let them in, send them to spam or reject them) and who to report to.
The new rules
- February 2024Gmail and Yahoo require SPF or DKIM from every sender, and SPF, DKIM and DMARC from anyone sending over 5,000 emails a day.
- May 2025Outlook, Hotmail and Live.com apply the same requirements and reject email that doesn’t meet them.
- TodayWithout authentication, your invoices, quotes and newsletters end up in spam or don’t arrive at all.
Frequently asked questions
Do I need SPF, DKIM and DMARC if I send few emails?
Yes. Gmail and Yahoo require SPF or DKIM from every sender, and without DMARC anyone can send fake emails with your domain to your customers. Setting up all three is free and takes minutes.
What happens if I don’t set them up?
Your emails are far more likely to end up in spam or be rejected, and your domain is left open to anyone who wants to spoof it for phishing.
Where are they set up?
In your domain’s DNS zone, wherever you manage it: your registrar, Cloudflare, Plesk… They are TXT records, and changes take from minutes to a few hours to propagate.
Why can’t you find my DKIM?
DKIM is published under a “selector” chosen by each provider, and it can’t be listed from outside. We try the most common ones; if you use another, find it in the DKIM-Signature header of a sent email (the s= value) and type it in the form.
Are your emails ending up in spam?
We set up SPF, DKIM and DMARC properly and watch the DMARC reports for you. We’ll get back to you within 24 h, no strings attached.