Most emails go to spam because the sending domain cannot prove it is genuine. Gmail and Yahoo have required SPF or DKIM from every sender since February 2024, and bulk senders also need DMARC, one-click unsubscribe and a spam complaint rate under 0.3%. Outlook introduced similar rules for bulk senders in May 2025.
The three records that prove who you are
- SPF lists the servers allowed to send email for your domain.
- DKIM adds a digital signature to each email so the receiver can check it was not changed.
- DMARC tells inbox providers what to do if SPF or DKIM fails, and sends you reports.
All three are DNS records. Your email provider (Google Workspace, Zoho, Brevo, Mailchimp and others) gives you the exact values to add at your domain registrar or host.
The rules for all senders
- Set up SPF or DKIM for your domain.
- Send over a secure (TLS) connection.
- Keep your spam complaint rate below 0.3%. Google recommends staying under 0.1%.
Extra rules for bulk senders
If you send 5,000 or more emails a day to Gmail or Outlook addresses, you also need:
- SPF and DKIM
- A DMARC record (a policy of “none” is the minimum)
- A From address on the same domain that passed SPF or DKIM
- One-click unsubscribe, with requests handled within two days
A common mistake with website forms
Many WordPress sites send contact form emails “from” a Gmail address. Your web server is not allowed to send for gmail.com, so the email fails DMARC and lands in spam or disappears. Send from an address on your own domain, such as contact@yourdomain.com, and use an SMTP plugin connected to your email provider.
Quick checklist
- Send from your own domain, never a free Gmail or Yahoo address.
- Add SPF, DKIM and DMARC records.
- Only email people who asked to hear from you.
- Put a clear unsubscribe link in every marketing email.
- Remove addresses that bounce or have not opened anything in six months.
- Check Google Postmaster Tools to see your spam rate.
Since November 2025, Gmail rejects mail that breaks the rules
Google gave senders almost two years to adjust. From November 2025 it stepped up enforcement, and messages that fail its requirements can now be delayed or rejected outright instead of quietly landing in spam.
Example records
Your email provider gives you the exact values, but they look like this. An SPF record for a domain that sends through Google Workspace:
v=spf1 include:_spf.google.com ~all
A starter DMARC record that collects reports without blocking anything yet:
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com
How to check your setup
- Send an email to a Gmail address you own
- Open it, choose Show original from the menu and check that SPF, DKIM and DMARC say PASS
- Read the DMARC reports for a few weeks before tightening the policy to quarantine or reject
- Watch your spam rate in Google Postmaster Tools
Mistakes to avoid
- Publishing two SPF records; a domain must have only one
- Adding so many services to SPF that it goes over the limit of 10 DNS lookups
- Jumping straight to a reject policy before reading DMARC reports
- Buying email lists
A 15-minute fix for small businesses
- Log in to your domain registrar or hosting DNS settings
- Copy the SPF and DKIM values from your email provider and add them
- Add a DMARC record with a policy of none and your own reporting address
- Change your website forms to send from an address on your domain
- Send a test email to Gmail and check that all three show PASS
Frequently asked questions
Do I need DMARC if I send only a few emails?
It is required for bulk senders and recommended for everyone, because it protects your domain from being spoofed.
What is a good spam complaint rate?
Stay below 0.1%. Google treats 0.3% as the upper limit for bulk senders.
Why do my website form emails go to spam?
Usually because the form sends from a Gmail or Yahoo address through your web server. Send from your own domain using an SMTP plugin.
Does Outlook have the same rules?
Outlook began enforcing similar requirements for bulk senders on 5 May 2025, including SPF, DKIM and DMARC.
Building a list from scratch? Read our email marketing guide for beginners.