You can write a great email and still lose half your audience if it lands in spam. Deliverability is the share of your emails that reach the inbox, and it depends on how you set up your domain and how you treat your list.
Gmail and Yahoo tightened their rules for bulk senders in 2024, and Gmail started rejecting more non-compliant mail from November 2025. This checklist covers what they ask for, plus the habits that keep your sender reputation healthy.
Quick checklist
| Check | Why it matters | Who needs it |
|---|---|---|
| SPF record | Lists the servers allowed to send for your domain | All senders |
| DKIM signature | Proves the email was not changed in transit | All senders |
| DMARC record | Tells inboxes what to do if SPF or DKIM fail | Required for bulk senders |
| Spam rate under 0.1% | Gmail’s recommended level; 0.3% is the hard limit | All senders |
| One-click unsubscribe | Required on marketing email for bulk senders | Bulk senders |
| Clean list | Bounces and inactive contacts hurt reputation | All senders |
1. Set up SPF, DKIM and DMARC
These 3 DNS records prove that your emails really come from you. Gmail’s sender guidelines require SPF or DKIM for everyone who sends to Gmail, and SPF, DKIM and DMARC for bulk senders.
- SPF lists the mail servers allowed to send on behalf of your domain.
- DKIM adds a digital signature to each message.
- DMARC tells receiving servers what to do with mail that fails those checks. A policy of
p=noneis the minimum Gmail accepts for bulk senders.
Your email platform (Mailchimp, Brevo, HubSpot and others) will give you the exact records to add in your domain’s DNS settings.
2. Watch your spam complaint rate
Gmail asks senders to keep the spam rate reported in Google Postmaster Tools below 0.1% and never reach 0.3%. That means fewer than 1 complaint for every 1,000 emails delivered.
The easiest way to stay under it is to email only people who asked to hear from you, and to make every email worth opening.
3. Make unsubscribing easy
Bulk senders must support one-click unsubscribe on marketing emails (the RFC 8058 standard) and process requests within 2 days. Most email platforms add this for you. A visible unsubscribe link in the footer also cuts complaints, because people who can’t find it tend to hit “report spam”.
4. Keep your list clean
- Remove hard bounces straight away.
- Use double opt-in for new sign-ups where you can.
- Never buy or rent email lists.
- Send a re-engagement email to contacts who have not opened in 3 to 6 months, then remove those who stay silent.
Our guide to email automation flows shows how to set up that re-engagement sequence.
5. Warm up new domains slowly
A new domain or IP address has no reputation yet. Start with small sends to your most engaged contacts and increase volume over a few weeks. Sudden large sends from a new domain look like spam to inbox providers.
6. Write emails people want to open
Engagement signals affect where future emails land. Clear sender names, honest subject lines and useful content all help. See our subject line tips for practical examples.
How to check your deliverability
- Set up Google Postmaster Tools for your sending domain.
- Send test emails to Gmail, Outlook and Yahoo accounts and check which folder they land in.
- Review bounce, complaint and open rates after every campaign.
Check these numbers monthly. Deliverability problems build slowly, and they are much easier to prevent than to fix. More guides are in our email marketing section.
