Email Deliverability: How To Land In The Inbox Every Time

You can write the best email of your life, and it only earns you money if it lands in the inbox. That is what deliverability means: the share of your emails that arrive where your reader will see them.

Here is the good news. Inbox placement is not luck and it is not a secret. Gmail, Yahoo and every other inbox provider publish what they want from senders, and the people who land in the inbox week after week all do the same handful of things. This guide walks you through every one of them, in order, with real examples for a demo business called Brightline Coaching and real ResultsAiX Mailer screens.

None of it is technical once you have seen it done. Most of it you set up once, in an afternoon, and the Mailer looks after the rest every time you send.

How Inboxes Decide

Every time you send, the inbox provider at the other end (Gmail, Yahoo, Outlook, Apple and the rest) asks three questions in a fraction of a second:

• Is this really from who it says? That is authentication: SPF, DKIM and DMARC.
• Do people want email from this sender? That is engagement: opens, clicks, replies, people moving you out of spam, and how rarely anyone presses “Report spam”.
• Does this sender behave like a professional? That is consistency: steady volume, a clean list, an easy unsubscribe and a real postal address.

Get all three right and the inbox becomes your normal home. Here is the path every email takes, and what earns its place at each step:

Reputation Is Built By Your Readers

Inbox providers keep a reputation for your sending domain, built from how real people treat your email. When people open, read, click and reply, your reputation rises and more of your email goes to the inbox. That is the whole game: send email to people who want it, in a way providers can trust, and keep doing it.

The signals they read most closely, and what the best senders do about each one:

Send From Your Own Domain

The first decision is the simplest and the most important. Send from an address on your own domain, for example hello@yoursite.com, through a professional sending service.

Your domain is your sending identity. Every good send adds to its reputation, and that reputation belongs to you. It travels with you if you change sending service, and it is what Gmail and Yahoo look at first. A free address such as a Gmail or Yahoo mailbox is made for personal mail, and those providers ask bulk senders to use their own domain.

What You Need

Your Domain Or A Sending Subdomain?

Many sending services let you authenticate either your main domain or a subdomain such as news.yoursite.com or send.yoursite.com. Both work well. A subdomain gives your marketing email its own reputation, separate from your everyday mail, and it is a tidy way to add a second sending service later.

Whichever you choose, keep the visible From address on your brand, for example hello@yoursite.com or sarah@news.yoursite.com, and authenticate exactly the domain that appears in it. That match is called alignment, and Part 3 shows you how it works.

Set Your Sender Once In The Mailer

In the ResultsAiX Mailer your sending identity lives in a sender profile: the From name, From email, Reply-To address and your postal address. Set it once under Settings and every broadcast and automation uses it. The postal address is added to the footer of every email automatically, directly under the unsubscribe link, and the Mailer holds a broadcast as a draft until an address is set, so every email you send is compliant.

SPF, DKIM And DMARC Made Simple

These three DNS records are how your domain proves an email really came from you. They sound technical, but each one is just a line of text you add once at your DNS host. Your sending service gives you the exact values to copy, and its dashboard turns green when they are in place.

Think of it like a letter from your business:

SPF: Your Approved Senders

SPF is one TXT record on your domain. It starts with v=spf1, lists each service allowed to send for you with an include:, and ends with ~all (everything else is treated as suspicious) or -all (everything else fails).

Brightline Coaching uses Google Workspace for everyday mail and SMTP2GO for its newsletter, so its SPF record looks like this:

Two habits keep SPF perfect. First, a domain has one SPF record: when you add a new service, add its include to the record you already have. Second, keep the list short. SPF allows up to 10 DNS lookups in total, which comfortably covers a mailbox provider and two or three sending services.

Many sending services also ask you to add a return-path (sometimes called a bounce domain or custom MAIL FROM), usually a CNAME on a subdomain of yours. That is what lets SPF line up with your own domain, and your service’s setup screen shows the exact record.

DKIM: Your Signature

With DKIM, your sending service signs every email with a private key, and you publish the matching public key in your DNS. Most services give you one to three CNAME records, which point to keys they manage and rotate for you. A few give you a TXT record with the key itself.

The names below show the shape. Your service shows the real ones on its domain verification screen, and you copy them exactly:

The part before ._domainkey is called the selector. Each service uses its own, so you can have DKIM for your mailbox provider and for every sending service side by side, with no conflict. Google asks for keys of at least 1024 bits and recommends 2048 bits where your service supports it.

DMARC: Your Instructions And Your Reports

DMARC is one TXT record at _dmarc on your domain. It tells inbox providers what to do when an email claiming to be from you fails authentication, and where to send daily reports. It also checks alignment: the domain in your visible From address must match the domain that passed SPF or DKIM. With DKIM set up on your own domain, that happens naturally.

Set up SPF and DKIM first, then add DMARC and tighten it in three calm steps:

The Gmail and Yahoo bulk-sender rules ask for DMARC with at least p=none, so stage 1 already meets them. The reports arrive as small XML files. A free DMARC report reader, or the reporting address your sending service offers, turns them into a simple pass rate. When every service you use shows close to 100% pass, you are ready for stage 2.

Adding The Records, Step By Step

The Gmail And Yahoo Sender Rules

Gmail and Yahoo publish a shared set of requirements for anyone sending email to their users, with extra requirements for bulk senders, and Gmail actively enforces them. The good news: they are the same habits this guide teaches, written down, and the ResultsAiX Mailer handles several of them for you automatically.

Who Counts As A Bulk Sender

Google defines a bulk sender as anyone who sends close to 5,000 messages or more to personal Gmail accounts within 24 hours. Mail from subdomains counts towards the main domain, and once you have reached that level, Google treats you as a bulk sender from then on. If your list is growing, the simplest plan is to meet the bulk-sender rules from day one. Then there is nothing to change as you grow.

The Requirements, Side By Side

Sources: Google’s Email sender guidelines and its sender guidelines FAQ (support.google.com), and Yahoo’s Sender Best Practices (senders.yahooinc.com). Both pages are updated from time to time, so glance at them once a year.

Spam Rate, In Real Numbers

The spam rate is the share of your delivered email that people mark as spam. Google calculates it daily from the reports of real Gmail users. To put the numbers in context:

That is why the habits in Parts 6 to 9 matter so much. People who asked to hear from you, who remember who you are, and who can leave with one click, very rarely press “Report spam”.

One-Click Unsubscribe, Done For You

Every broadcast from the Mailer carries the two headers the rules ask for: List-Unsubscribe, with a personal unsubscribe link, and List-Unsubscribe-Post: List-Unsubscribe=One-Click. Gmail, Yahoo and Apple Mail read them and show their own Unsubscribe button beside your name. When someone uses it, the Mailer removes them straight away.

The visible link sits in the footer of every email too, with your postal address beneath it. The Mailer’s unsubscribe link is also scanner-safe: an inbox security scanner that “visits” links does not unsubscribe a real reader, because removal happens on the real button press. You can even click your own unsubscribe link to test it, without leaving your list.

A footer link called Manage your preferences lets people update their name, change their email address or leave individual lists, which keeps people who only want less email on your list.

Google Postmaster Tools

Google Postmaster Tools is a free dashboard from Google that shows how Gmail sees your email: your spam rate, your authentication results, and whether you meet the sender requirements. It is the closest thing to a report card from the biggest inbox provider in the world, and it takes ten minutes to set up.

Setting It Up

What Each Dashboard Shows

Google adjusts these dashboards from time to time, so the names on your screen may differ slightly. The ideas stay the same.

How To Read It, In 5 Minutes A Week

Your Most Engaged People First

This is the single most powerful habit in email marketing, and it is the one most people have never heard of. Inbox providers learn from how people react to each send. When the first people to receive your email open it, click it and reply, providers see a wanted email and place it in the inbox for everyone else too.

So the best senders do not send to their whole list at once. They send to their most engaged people first, watch the results, then widen the audience.

Three Groups, Three Ways To Treat Them

The Audience Health Check

In the Mailer, every broadcast’s Audience step shows this split for you, under the recipient count: how many people opened or clicked in the last 30 days, 31 to 90 days ago, and not in 90 days, with the share of each. When half or more of a big audience has been quiet for 90 days, it suggests the two smart options: leave the quiet people out, or send in waves.

Send In Waves

On the broadcast’s Review & send step, choose Send in waves, most engaged first. The Mailer splits the audience into the three groups above:

Each wave checks the audience again at the moment it sends, nobody ever receives the email twice, and anyone who unsubscribed in between is left out. Empty waves are skipped.

Build Segments Around Engagement

Segments are groups defined by rules, and they update themselves as people open and click. Brightline Coaching keeps four ready to use: engaged in the last 30 days, engaged 31 to 90 days ago, workbook readers who clicked, and people moved in from the old platform who have not been emailed yet. With an AI key connected, you can describe a segment in plain English, for example “opened or clicked in the last 60 days and tagged workbook”, and the AI writes the rules for you, with a live count.

Two more Mailer tools help here. Every subscriber carries an engagement score out of 100, recalculated daily, which you can filter on. And on the Subscribers screen, the Last Contact filter includes choices such as no contact in 90 or more days, so you can see exactly who to hold back while you warm up.

Warming Up Gradually

Inbox providers trust what they know. A brand new domain, a new sending service, or a list you have not emailed for a while has no recent history, so the best start is a gradual one: small, engaged sends that grow day by day while your reputation builds.

Warm up when any of these is true:

• You are sending from a new domain or subdomain for the first time.
• You have moved to a new sending service or a new account.
• You are bringing back a list you have not emailed for two months or more.
• You are moving your list in from another email platform (Guide 5 covers the whole move).

The Mailer’s Warm-Up, Per Sending Connection

Go to AiX Mailer, then Sending, and scroll to Send Rotation & Warmup. On a connection’s row, tick Warm up and pick a pace:

Then send as normal. Each day the queue sends up to that day’s cap, and the rest waits and continues the next day. Nothing fails and nothing is lost. The row shows where you are, for example Warming up: day 4, today’s cap 800, and says Warmup complete when it reaches the connection’s daily limit.

The same panel shows an authentication badge for each connection: green when your DNS proves that service may send for your domain. Tick Strict DKIM guard and only green connections take part in rotation, so every email that goes out is aligned.

The Hourly Ceiling And Your Sending Pace

A steady pace looks professional. Under Settings, the Mailer gives you the controls:

• Never send more than this many broadcast emails an hour: one ceiling for every broadcast together, spread evenly across the hour. 1,500 means about 25 a minute, never more than 1,500 in any hour. Automation and welcome emails are never held back.
• Queue batch size and interval: your normal speed. A batch of 1,500 with an interval of 3,600 seconds releases a steady 1,500 an hour in small even sips.
• Sending window: only send broadcasts between, for example, 08:00 and 20:00 in your site’s timezone. Outside it the queue waits and resumes on its own.
• Delivery guard: if more than 5% of the last 200 sends fail, that broadcast pauses itself and emails you, and resuming is one click.
• Seed addresses: your own Gmail, Outlook and Yahoo mailboxes receive a copy every so many sends during a dripped broadcast, so you can see inbox placement while it sends.

Each broadcast can also drip at its own speed, set on its Review & send step. While it sends, the report shows the progress, the time it will finish and buttons to pause or re-pace it.

Your 4-Week Warm-Up Plan

Here is a plan that works for a new domain or a list you are bringing back. The numbers are daily sends, and they always go to your most engaged people first. If your list is smaller, you simply finish sooner.

Keeping Your List Clean

A clean list is a list of real people who want your email. It opens more, clicks more, buys more, and costs less to send to. List hygiene is four small habits, and the Mailer does most of each one for you.

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1. Bounces Are Removed Automatically

A hard bounce means the address or domain does not exist. The Mailer adds it to your suppression list immediately. A soft bounce is temporary (a full mailbox, a busy server), so the address stays and the bounce is recorded. If one address soft bounces five times within 90 days, it is treated as gone. Every bounce is logged with its reason and the service that reported it.

For this to work, your sending service reports bounces back to the Mailer through a webhook. On the Sending tab, each service shows its own webhook URL with a Copy URL button. Paste it into your sending service’s webhook settings and switch on the bounce, spam complaint and unsubscribe events. It takes two minutes and it is one of the best things you can do for your reputation.

2. Unsubscribes And Complaints Leave For Good

An unsubscribe from a broadcast takes the person off the list that email was sent to. The global unsubscribe stops everything and adds them to suppression. A spam complaint reported by your service is suppressed immediately and permanently. The suppression check runs at the moment of every send, so no list, segment or import can bring those people back.

3. Watch List Health After Every Send

In Reports, the List Health section shows unsubscribes, bounces and spam complaints for any date range, each compared with the period before, and the latest people behind them. The benchmarks to keep in mind: complaints under 0.1% of what you send, and bounces under 2%.

The Deliverability tab holds the full suppression manager: the totals by reason, a search for any address, a Never email box to block an address by hand, Allow again if one landed there by mistake, plus import and export.

4. Re-Engage The Quiet, Then Let Them Go

People go quiet for ordinary reasons: a new job, a full inbox, a change of interest. A short re-engagement series wins many of them back, and it tells you clearly who has moved on.

Verify Leads: Know Who Is Real

The Mailer’s Verify Leads screen sorts your whole database into clear groups: alive, cold, unknown (no history yet), typo domains such as gmial.com with a one-click spelling fix, dead domains that cannot receive mail, masked addresses, and role addresses such as info@. It runs on your own site, and you choose what to do with each group.

Writing Emails People Want

Everything so far gets your email to the door. What you write is what makes people glad to open it, and glad readers are the best deliverability strategy of all. Here is what the best email writers do.

Set The Expectation At Sign-Up

Tell people on your form what they will get and how often: “A short coaching tip every Tuesday, plus the occasional offer.” Then do exactly that. People who get what they signed up for open, and very rarely report spam. For extra proof of consent, the Mailer offers double opt-in list by list: new subscribers confirm with one click before they become active, which gives you a smaller but very engaged list.

Write Like A Person

Let The Mailer Check It Before You Send

Inside the broadcast composer, with an AI key connected, three tools help:

• Subject lines: ten suggestions, each with a different angle (curiosity, benefit, story and more) and a matching preheader.
• Inbox score: a score out of 100 with a plain checklist: spam-trigger phrases, broken merge tags, image-to-text balance, link density and formatting.
• Preview as a real subscriber, and a test send to your own inbox, so you see exactly what your reader will see.

Names are tidied too. With Capitalise names in emails switched on, “sarah” and “SARAH” both go out as “Sarah”, while the name stored on the subscriber is left as they typed it.

Tag People By What They Do

Every broadcast has a Tagging step. Add tags when someone opens, when someone clicks any link, or per link: a click on your coaching programme link can tag someone differently from a click on your blog post. Each tag can start an automation instantly. Tag clickers of your workbook link and send them the next step. Tag openers and you know who is engaged right now, without guessing.

Send On A Rhythm

Choose a rhythm you can keep, such as one email a week on the same day, and keep it. A steady, expected email builds a habit in your readers and a steady pattern for inbox providers. A plan on the Mailer’s calendar makes it easy.

What The Mailer Does For You

Here is every ResultsAiX Mailer feature from this guide in one place, with where to find it.

Your Deliverability Checklist

Print this page and tick it off. The first group is set up once. The second is a quick look before every big send. The third is your weekly habit.

Set Up Once

Before Every Big Send

Every Week

Questions People Ask

What To Read Next

This is Guide 4 of 15 free AiX Training Guides, each with its own free PDF. If you are bringing a list across from another email platform, Guide 5 is your next read: it walks you through the whole move, and it builds on everything here.

Your First Step, Today

Open the Mailer’s Deliverability tab and run the check on your sending domain. If anything is still to add, add it tonight. Then sign up for Google Postmaster Tools. That is your foundation done, and every email you send from here builds on it.