How to Improve Email Deliverability: A Plain Checklist

How to improve email deliverability comes down to a short, plain checklist. No tricks. Just the steps that get your mail into the inbox and keep it there.

Most inbox trouble comes from three things. The mail can't prove who sent it. The list is full of people who don't want it. Or the mail reads like spam. Fix those three, and most of the problem goes away.

What email deliverability means

It means your email lands in the inbox. Not in spam. Not blocked. Not lost.

Sending is not the same as landing. Your tool can say sent, and the mail can still end up in a spam folder. So the real goal is the inbox, not the send.

Gmail, Yahoo and the rest decide where your mail goes. They look at who you are, how people react to your mail, and how you send it. You can't control them. You can give them good reasons to trust you.

How to improve email deliverability, step by step

1. Set up SPF, DKIM and DMARC for your domain.
2. Send from your own domain, not a shared one.
3. Meet the Google and Yahoo sender rules.
4. Add a one-click way to opt out, and a clear link in the email.
5. Only mail people who asked for it.
6. Stop mailing people who never open or click.
7. Write like a person, not an ad.
8. Send at a steady pace.
9. Watch your spam rate.

Here is each one in plain words.

Prove who you are: SPF, DKIM and DMARC

These three are records you add to your domain. They let an inbox check that the mail came from you.

• SPF lists which servers may send mail for your domain.
• DKIM adds a signed stamp to each email, so the inbox can tell it was not changed.
• DMARC tells the inbox what to do when a check fails, and ties the checks to the name in your From line.

You don't need to write these by hand. Your email tool gives you the records. You paste them into your domain settings.

If you use Klaviyo, know this. By default, most accounts start on a shared Klaviyo domain. Your mail can show as via klaviyomail.com. A branded sending domain fixes that, and gives you a name of your own with inbox providers.

To set it up in Klaviyo, click your company name in the bottom left. Go to Settings, then Domains, then Add Domain. Klaviyo can also make a basic DMARC record for you, if your domain doesn't have one yet. Here is Klaviyo's guide to a branded sending domain.

Meet the Google and Yahoo rules

Gmail and Yahoo both post their rules for senders. They are close. Here is the short form.

Google calls you a bulk sender if you send more than 5,000 messages a day to Gmail accounts. Google also sets a stricter goal: keep your spam rate under 0.1 percent, and never reach 0.3 percent.

Yahoo adds one more. Honor opt outs within 2 days.

Read them in full: Google's sender rules and Yahoo's sender rules. Ask your email tool if it adds the one-click part for you.

Keep your list clean

A clean list matters as much as your setup. People who want your mail open it. People who don't may mark it as spam.

• Only mail people who said yes. Never buy a list. Never add people you met once.
• Think about double opt-in. A second click to confirm keeps fake and mistyped emails out.
• Let hard bounces go. In Klaviyo, a profile that hard bounces gets suppressed, so flows skip it.
• Sunset the quiet ones. If someone has not opened or clicked in months, ask once if they still want your mail. Then stop.
• Make it easy to leave. An easy opt out is better than a spam click.

The quiet ones matter. If they never open, why keep sending? Our post on the sunset flow in Klaviyo shows how to do this on autopilot.

Write like a person

Gmail counts how often people mark your mail as spam. So write mail people want to open.

• Use a From name people know, like your brand or your first name.
• Make the subject match what is inside.
• Skip all caps. Skip a row of shouty marks at the end.
• Don't send one big image with no text.
• Keep the links few, and send them to your own site.
• Put the opt out link where people can find it.

None of this is magic. It is just what a real person's email looks like.

Send at a steady pace

Sudden spikes look odd. Say you send 500 emails a week. Don't jump to 50,000 overnight. Grow step by step.

The same goes for a new domain. Start with your most active readers, the ones most likely to want it. Then widen the send over a few weeks.

Ways to test your inbox rate

• Google Postmaster Tools. It shows your spam rate, your reputation and your checks for mail sent to Gmail. You add your domain and prove you own it. If you send very little, it may show no data.
• Klaviyo's Inbox testing. In Preview & test, it shows how your email looks across many inboxes.
• Your own accounts. Send a test to a Gmail, a Yahoo and an Outlook inbox. See where each one lands.

Those email rules you keep hearing about

What is the 30/30/50 rule for cold emails?

It is a rule of thumb from cold email blogs, and they don't agree on it. One splits effort into personal touch, value and follow-up. Another splits it into subject lines, inbox rate and follow-up. The numbers add up to 110. Use it as a loose prompt, not a rule.

What does the 3-21-0 email rule mean?

We looked and could not find a clear, shared meaning for it. Gmail and Yahoo don't use it. If a rule has no source, skip it. Follow the rules the inboxes publish.

How do you fix your email deliverability?

Start with your setup. Check SPF, DKIM and DMARC, and send from your own domain. Then clean your list and stop mailing people who never open. Watch your spam rate in Postmaster Tools, and keep it low.

Slow and steady wins the inbox

Inbox trust is built over time. Prove who you are, mail people who want it, and make it easy to leave. Do that, and the inbox works with you.

To check the whole setup in one go, the Email Deliverability Audit Claude Skill has Claude look at your SPF, DKIM, DMARC and list health, then lay out a 30 day plan to fix what it finds. On Klaviyo? We can also set up your flows for you.