Landing in the inbox
Why your emails end up as spam, and what actually fixes it.
9 min read
Writing a good email is pointless if it doesn't arrive. Deliverability is the invisible half of the job: it's decided before you send, through technical settings and how you've behaved up to that point. Here's what matters, in order.
Before reading on, you can look at what your DNS already says: the SPF, DKIM and DMARC checker reads all three records for any domain, free and without an account.
What an inbox provider checks
In a fraction of a second, Gmail decides where to put your message. It looks at two things: who you are, and how you've behaved.
'Who you are' is proven by domain authentication. 'How you've behaved' is read from your bounces, complaints, and past open rates.
The first is fixed in an hour. The second takes months to build and days to destroy.
Proving who you are, once
SPF lists the servers authorized to send on your behalf. DKIM signs each message. DMARC says what to do when one of the two fails.
Three roles, six lines to copy into your domain registrar's interface. Since February 2024, Gmail and Yahoo require them from anyone sending in bulk: without them, it's no longer a matter of probability — your email goes to spam.
It takes fifteen minutes, done once, and it's the only chapter on this page that's fixed by a setting. The exact steps are in the domain setup guide; everything else here depends on you, not a DNS record.
Never email a dead address
A hard bounce means the address doesn't exist. Each new attempt counts against you.
Above a 5% bounce rate over the last thirty days, the sending account goes under review, then suspension, and delivery degrades for everything you send — including to valid addresses. Mailcheer applies this threshold to every workspace from fifty sends in the period; during a campaign, sending stops on its own if, past fifty messages, a quarter come back as errors.
That's why a suppression list must be automatic and impossible to bypass: an address that hard-bounces must never come back, even through a file re-import.
Spam complaints: the most damaging signal
When someone clicks 'report as spam', the inbox provider attributes it to you. The tolerated threshold is very low: 0.1%, meaning one complaint per thousand sends.
The primary cause of complaints isn't the content: it's not being able to find the unsubscribe link. Make it visible. Someone who unsubscribes is doing you a favor; someone who reports you costs you dearly.
Ramping up gradually
Going from zero to ten thousand sends overnight from a new domain is the surest way to get filtered.
Start small, with your most engaged contacts, and scale up over two to three weeks. Inbox providers watch consistency as much as volume.
What doesn't work
Banned words. The idea that writing 'free' sends email to spam is a persistent myth. Modern filters look at your reputation, not your vocabulary.
Online spam score testers. They give you a score based on 2010 criteria. A good score has never made an email arrive.
Paying for a dedicated IP address when you send too little. Below tens of thousands of monthly sends, a dedicated IP doesn't have enough volume to build a reputation. It hurts more than it helps.
Other guides
Deliverability isn't a setting to find — it's a habit to keep. Authenticate your domain, remove dead addresses, make unsubscribing easy — the rest follows.
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