Email deliverability: how to stay out of spam

Deliverability is whether your email is seen at all: the best campaign doesn’t work if it lands in spam. Spam filters judge the sender’s reputation first, so deliverability depends not only on content but on technical setup and sending discipline.
Below are the main reasons emails don’t arrive and what to do about it.
Why do emails land in spam?
The reasons are almost always in the sender’s reputation, not the specific email.
What damages deliverability
- An unverified domain without SPF/DKIM records.
- Sending to bought or non-consenting contacts.
- Sharp volume spikes from a new domain.
- Spam complaints and a high unsubscribe rate.
What to set up first?
Verify your domain via SPF/DKIM — it’s the basic trust signal for mail providers. Without these records, even an honest campaign raises more doubt with filters.
How do you maintain deliverability?
Send only to those who consented, keep a moderate frequency and warm up new domains gradually. Regularly test where emails land to spot a problem before it hits sales.
Frequently asked questions
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01 Why do emails land in spam?
The most common reasons are an unverified domain, sending to non-consenting contacts, sharp volume spikes and aggressive spam words in the subject. Spam filters judge the sender's reputation, not just the email's content.
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02 What are SPF and DKIM and why do you need them?
They're technical records that confirm emails really come from your domain. Without them, mail providers doubt the sender more and the chance of landing in spam rises. Setting them up is a basic deliverability step.
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03 Can you buy lists for campaigns?
No. Sending to bought or non-consenting contacts brings complaints and unsubscribes that sharply damage domain reputation. One such campaign can hurt deliverability for a long time, even for loyal subscribers.
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04 How do you «warm up» a new sending domain?
Start with small volumes to your most active subscribers and increase gradually. A sharp start with a large send from a new domain looks suspicious to filters and hurts deliverability.
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05 How do you know there's a deliverability problem?
By a drop in opens with no content change, rising spam complaints and emails not reaching test inboxes. Regularly send a test to several mail providers to see where emails actually land.



