Here at Sona, we’ve sent out over a million cold emails on behalf of our 250+ clients. Everything from small businesses to multinational enterprises, across 30+ verticals from SaaS to finance to snacks.

We have run the spam gauntlet hundreds of times and been battered by every email-blocking issue imaginable, which means we’ve been in a unique position to discover best practices when it comes to avoiding spam jail.

It’s never fun getting caught in spam, but we’ve gotten pretty good at preventing spam triggers from destroying our clients’ outbound campaigns, and we’re going to share some uncommon tips that we’ve learned in this article.

Tip #1: Turn off opt-out links and tracking.

This advice goes against what you’ll read on other blogs. Many articles will suggest adding opt-out links so that your prospects click ‘unsubscribe’ instead of ‘mark as spam,’ but what these links do is add bits of code to your email or signature that make it very clear that your email wasn’t sent by a human.

The same goes for tracking how many “opens” and “clicks” your emails get.

The problem is that email providers look for these bits of code when they decide which emails to send to the spam folder, so you’re already shooting yourself in the foot by adding them.

Focus instead on making your copy feel both relevant and personal, and maybe even a little informal, so that prospects will simply delete your email if they aren’t interested, rather than marking it as spam.

Tip #2: Make sure your email addresses are valid before sending.

So you’ve scored yourself a list of 5,000 email addresses. No harm in just blasting all of them with your awesome email content, right?

Actually no, because a good chunk of those email addresses are likely to bounce if you haven’t first verified the addresses with a service like NeverBounce.

The more bounced or invalid emails you send, the more likely it is you’ll get into spam trouble because email providers have bounce rate policies that affect your inbox deliverability, sender reputation, and IP address health.

Tip #3: Use your first 1,000 leads as a test.

It’s really important to measure the results of every campaign and adjust accordingly. Not just for the purpose of improvement and optimization, but also for the purpose of avoiding unforeseen catastrophes.

We’ve discovered that tracking the ratio of “interested” responses against “not interested” responses gives us a solid indication of how relevant our campaign is to our audience. And while this ratio doesn’t directly measure your sender reputation, it does give you a very good indirect indication of how likely it is that you’ll get caught in spam.

If you aren’t getting at least twice as many positive responses as negative ones (neutral responses can be ignored) then you can expect deliverability to become a problem for you in the future. Make your copy more personalized to improve this ratio.

As a rule of thumb, you’ll need at least 1,000 sends under your belt before your campaign’s results are statistically significant and useable.

Tip #4: Never use the same email content across multiple email domains.

You’ve probably heard that you should be using a separate domain for sending cold emails, like a .co instead of a .com, or a slight variation on your existing domain (ie. or

This is good advice that will keep your domain reputation safe in case you do ever get into spam trouble.

One additional thing we wanted to mention if you’re already doing the above is that you should always make sure you’re using different email copy when you send from different email domains.

If you send the same email copy from two different domains, this is a major spam trigger. So don’t do it, even the copy is working really well.

If you’re sending cold emails, do it right the first time.

We know it’s tempting to ignore some of this advice because it feels like too much work, but if you’re sending cold emails willy-nilly and telling yourself, “Oh, it’ll be fine,” we’re here to tell you that it probably won’t.

Not to be the bearers of bad news… we just don’t want to see you hurt your sales results by getting caught in spam when it can be avoided with a few preventative measures like the ones explained in this article.

Looking for more advice on dealing with spam when sending cold emails? Check out our previous articles below.

Sending cold emails? You may be in spam trouble and not even know it. Here's how to find out.

Cold emails getting you into spam issues? Here's how to fix it.