5 tips to stay out of the spam folder

If you work with email marketing you may have been here. You spent a long time on a good newsletter — the copy, the graphics and the message are right. Then you press send and find that many of your recipients never saw it in their inbox at all. It landed in spam.

It is a frustrating place to be, and poor deliverability eventually means poor results for everything you communicate. Fortunately there are things you can do about it.

Mail clients sort on many signals

There was a time when avoiding a handful of words was enough to stay out of the spam folder. Those days are long gone. In the late 2000s, “spam” stopped meaning only the illegal and unethical and started to cover the unwanted and irrelevant as well.

With roughly 90 per cent of all email classified as spam, clients like Gmail and Outlook have to work constantly at filtering out what nobody needs. They want you to receive only the mail you intend to read. Too much irrelevant mail creates so much noise that you stop spending time in the platform — which is not in their interest either.

So how do they judge what an individual recipient finds relevant?

They are not about to publish every signal they sort on; that would simply help the fraudsters. But the broad shape of the process is known.

There is a coarse pass first, where technical and content-level signals decide whether your message gets through at all. Then comes a more personal pass, based on each recipient’s own past behaviour. Which is why the same message reaches some recipients and lands in spam for others.

Your deliverability also depends on your overall reputation, built from how your previous messages performed. Keep sending irrelevant email and that reputation only gets worse.

There is a note at the end on what to do if your reputation is already damaged. Let us start with how to avoid getting there.

1. Get the technical part right

Set up SPF, DKIM and DMARC.

When it comes to deliverability, your SPF record is the foundation. It declares that your email system is allowed to send on behalf of you and your domain. If you use Ubivox to send newsletters, the receiving server sees Ubivox attempting to send using your domain — and your SPF record is what says you approved that.

The whole assessment of your sender reputation starts there. Without it, your mail will end up in the spam folder more often. Our post on why SPF matters and how to set it up covers it in detail.

If you change email platform, remember to update your SPF record — the new platform needs the same approval.

DKIM lets a receiving server check that your email really did come from you and your domain. Technically, an invisible digital signature is added to the message, which the receiving server uses to confirm it is genuine. Where a server is in doubt whether it is really you sending — or a phishing attempt — the message goes to spam unless DKIM is in place.

DMARC ties SPF and DKIM together and lets you, as the domain owner, tell receiving servers what to do with mail that claims to come from your domain but does not line up with your SPF and DKIM. It also reports unauthorised mail sent in your name, which you can use to warn your own recipients if fake messages are circulating.

DKIM and DMARC are extra layers of security and they improve deliverability. It sounds technical, but it is worth the time. Write to support if you are unsure where to start — we set this up with customers regularly.

2. Clean your lists regularly

Because your reputation rests partly on whether you send relevant content, your recipients play a large part in it. They are the ones who decide what is relevant — deliberately, by not opening or engaging, or without meaning to, when the mail client routes you straight to spam based on their past behaviour.

So it is better for your deliverability to have fewer recipients who actually engage than a great many who never open anything. In the second case, the mail clients conclude that your recipients do not find your content relevant, and your reputation suffers.

Clean your lists regularly, so you are not sending to people who have no interest in hearing from you. Your open rate rises as a matter of arithmetic when you remove inactive recipients — and that strengthens your reputation.

While you are at it, make sure the unsubscribe link is obvious. Having no unsubscribe link damages your reputation, and in most jurisdictions it is not legal either. It is also worth remembering that unsubscribes are not a disgrace; they help keep your list clean. The problem is a lot of unsubscribes over a short period — that is a signal to find out why.

Most email platforms let you automate the cleaning. Set up an automation that removes a member from the list if they have not engaged with anything for, say, six months.

3. Keep a sensible balance of images and text

Once the technical side is sorted and your lists are clean, you can turn to the content itself.

We often see organisations drop in a single illustration or an image with the text baked into it, instead of real text. It is tempting, because it lets you design something good-looking in Photoshop or Canva. There is one problem: if there is not enough text, the mail clients cannot judge whether your message is relevant to the recipient.

So avoid putting too much text inside your images, and use a real text block instead, giving the clients something to assess. Around 500 words is a reasonable rule of thumb. Mostly, aim for a good balance — and remember that too many images can also make the message too heavy to be delivered.

4. Avoid spam trigger words

Mail clients look at far more than the words in your message these days, but the words are still part of the sorting.

Think of phrases like free, 100% satisfaction, amazing offer, win a, prize. Different clients keep different lists, but you can find general lists of words to avoid.

If you genuinely cannot write your message without one of them, it is not the end of the world. Just be aware that some recipients may not see it in their inbox — and that using them often will gradually damage your reputation.

Few people can hold the whole list in their head. The practical advice is: if you are unsure about a word, check it, and consider rewriting the sentence. As a rule of thumb, avoid clickbait.

5. Avoid heavy emails

As a starting point, keep your emails under 100 KB. Gmail, among others, clips a message over 102 KB. So leave out images, text and links that do not serve the message.

Keep it short, simple and relevant. If you have a lot of information, link to a landing page on your site where you can go into depth. The same goes for attachments: never attach files, as it lowers your credibility with the mail clients. Put the file on a landing page where people can download it instead.

What if my reputation is already damaged?

Rebuilding takes a long time. It requires your recipients to start engaging with your email again — which is hard when it is going to their spam folder. That is why the advice above is worth following before you get there.

React when open rates start falling, not after. Falling open rates mean worse deliverability, and from there the snowball rolls towards a damaged reputation.

Remember too that your reputation follows you if you change email platform. Even so, it is a good idea to clean your lists before you start in a new one.

If the reputation is beyond saving, the last resort is changing domain name — which in many cases means changing the organisation’s name as well. Very few people have the time or the appetite for that.

Which is the real argument for giving deliverability your attention now.