If you’ve ever spent time writing the perfect email campaign, only to discover it landed straight in your customers’ spam folders, you’re not alone.
Poor email deliverability is one of the most frustrating issues for small businesses and startups. You can have a great offer, a strong message, and a beautifully designed email, but none of that matters if people never see it.
The good news? You can fix this.
Email deliverability isn’t a mysterious black box. Once you understand what causes your emails to be flagged, you can take practical steps to keep them out of spam and land safely in the inbox.
In this guide, we’ll break down exactly how email deliverability works, the common mistakes small businesses make, and how to stop your emails going to spam.
What Is Email Deliverability?
Email deliverability refers to how successfully your emails reach your subscribers’ inboxes rather than their spam or junk folders. Think of it as reputation management for your email domain. If email providers such as Gmail, Outlook, and Yahoo believe you’re trustworthy, your messages are delivered. If not, they’re filtered out.
For small businesses, good deliverability is essential. Without it, your campaigns underperform, your engagement drops, and your email marketing becomes far less profitable.
Why Emails Go to Spam
Before we look at how to fix the problem, it’s important to understand what triggers spam filters. Email providers use hundreds of signals to decide whether your message is legitimate or suspicious. Here are the most common reasons emails go to spam:
- Poor domain authentication:
If you haven’t set up SPF, DKIM, and DMARC, email platforms can’t verify that your messages are genuine. This is one of the biggest causes of deliverability issues and affects thousands of small businesses. - Using a free email address:
Sending from a Gmail, Yahoo, or Outlook address instead of your business domain immediately reduces your credibility. Most email marketing platforms now require a domain-based email for this reason. - Low engagement rates:
If people aren’t opening your emails or clicking through, inbox providers may decide your messages are unwanted. - A cold or outdated list:
Sending emails to inactive, old, or purchased lists leads to high bounce rates, spam complaints, and damaged reputation. - Spam-triggering words and formatting:
Phrases like “FREE!!!”, poor grammar, broken links, or overly promotional content may activate spam filters. - Sending too many emails at once:
If your domain suddenly sends a large volume of messages, email providers may suspect your account has been hijacked or abused. - Poor-quality email software:
Cheap or outdated platforms often lack the deliverability tools needed to maintain a healthy sending reputation.
Once you know what causes the problem, you can fix it, and that’s where the real improvements happen.
How to Stop Your Emails Going to Spam: A Practical Guide for Small Businesses
The steps below will help you improve your email deliverability and ensure your campaigns reach your audience, not the spam folder.
1. Set Up SPF, DKIM, and DMARC (Your Email Authentication Trio)
This is the most important step. Email authentication proves that the email is genuinely coming from your domain and hasn’t been spoofed.
- SPF:
An SPF record states which servers are allowed to send emails on your behalf. - DKIM:
DKIM adds a digital signature to your emails, confirming they haven’t been tampered with. - DMARC:
DMARC tells receiving email providers what to do if an email fails SPF or DKIM checks.
If these aren’t set up correctly, your emails may be blocked automatically, even if everything else is perfect.
Most email platforms like Google Workspace, Microsoft 365, MailerLite, and Mailchimp provide simple DNS records you can copy and paste into your domain settings. Once done, your deliverability almost always improves overnight.
2. Send Emails From Your Own Domain
Never send marketing emails from:
Not only does this look unprofessional, but email providers often reject promotional messages sent via free email addresses.
Instead, use something like:
hello@yourdomain.co.uk
info@yourdomain.co.uk
marketing@yourdomain.co.uk
If you don’t have a domain-based email yet, it’s worth setting one up, especially since Google (Gmail) and Yahoo introduced new sender requirements in 2024/2025.
3. Use a Reputable Email Marketing Platform
Not all email tools are created equal. Some have slow servers, poor spam prevention, or weak authentication. This harms your deliverability.
Look for platforms with:
- strong deliverability records
- automatic authentication support
- list-cleaning tools
- easy unsubscribe management
Great options for small businesses include:
- MailerLite
- Mailchimp
- Klaviyo (for eCommerce)
- ConvertKit
- HubSpot (if you need CRM features too)
Using a modern platform gives you better infrastructure and increases your chances of landing in the inbox.
4. Clean Your Email List Regularly
Email lists naturally decay by around 20–30% each year. People change jobs, email addresses become inactive, spam traps appear, or subscribers lose interest.
Sending to bad addresses is a fast way to damage your sender reputation.
Make list cleaning part of your email routine:
- remove inactive subscribers (people who haven’t opened in 6–12 months)
- avoid buying email lists – this is illegal and destroys your reputation
- use double opt-in if you’re getting lots of fake sign-ups
- use tools like ZeroBounce or NeverBounce if you suspect spam traps
A clean list means better engagement, fewer bounces, and less chance of hitting the spam folder.
5. Avoid “Spammy” Words and Formatting
You don’t need to write like a robot, but you should avoid certain phrases that look suspicious to spam filters, especially when combined with bold formatting or over-the-top punctuation.
Examples to avoid:
- “GET RICH QUICK!!!”
- “FREE FREE FREE”
- “CLICK NOW OR MISS OUT!”
Instead, use natural, conversational language, just like you would speak to a real person.
A good rule of thumb:
Write for humans, not algorithms.
6. Warm Up Your Email Domain
When you send from a new domain or begin sending at higher volumes, email providers don’t trust you yet. You need to “warm up” your sending reputation gradually.
Start with:
- small batches of 20–50 emails
- sending to your most engaged subscribers
- gradually increasing the volume over a few weeks
If you blast 5,000 emails from day one, you’ll almost certainly get flagged as spam.
7. Make Your Unsubscribe Link Easy to Find
It may sound counterproductive, but having a clear unsubscribe link is essential for good deliverability.
If people can’t find the unsubscribe button, they mark your emails as spam instead, which damages your reputation far more.
Make it easy, make it obvious, and don’t try to hide it.
8. Improve Engagement With Better Email Content
Email providers monitor how subscribers interact with your messages. Higher engagement means better inbox placement.
Try:
- asking a question to increase replies
- adding personalisation using the subscriber’s name
- segmenting your list (don’t send the same email to everyone)
- improving your subject lines
- testing the best send times for your audience
Aim for emails people look forward to receiving, not ones they delete instantly.
9. Add a “Safe Sender” Message to Your Welcome Email
This is a small but powerful step.
In your welcome email, ask subscribers to:
“Add us to your contacts” or
“Move us to their Primary inbox”
When users take these actions, it signals to their email provider that your messages are important. This dramatically improves future deliverability.
10. Monitor Your Deliverability Regularly
Even once everything is set up correctly, deliverability can still change over time. Keep an eye on:
- open rates
- bounce rates
- email engagement
- spam complaints
- domain health
Many email platforms include built-in tools, but you can also use:
- Google Postmaster Tools
- Microsoft SNDS
- Mail-Tester.com
Watching your deliverability means you can spot issues early and fix them before they impact sales.
Common Myths About Email Deliverability
Small business owners often worry about email marketing because of misinformation. Let’s clear up a few myths:
“If people mark my email as spam once, my domain is ruined.”
Not true. Occasional spam complaints are normal. You only need to worry if they become frequent.
“Images cause spam issues.”
Images are fine, as long as you don’t rely on them for all your content. Always include alt text and a balance of images and text.
“Sending fewer emails improves deliverability.”
Actually, consistency is more important. Sudden changes in frequency can hurt your reputation.
“A bigger list is always better.”
A smaller, engaged list will outperform a large inactive one every time.
How Better Deliverability Helps Your Business Grow
Improving email deliverability isn’t just about avoiding spam filters. It has a real impact on revenue and customer relationships.
You’ll see benefits such as:
- higher open rates
- more clicks to your website
- more sales from campaigns
- stronger brand reputation
- better engagement with your audience
Email remains one of the most cost-effective marketing channels available. When your messages consistently reach the inbox, your investment pays off faster.
Final Thoughts
Email deliverability may sound technical, but with the right steps, it becomes manageable, even for small businesses and startups. By authenticating your domain, keeping your list clean, writing clear and helpful emails, and using reliable tools, you give your campaigns the best possible chance of success.
If you want long-term results with email marketing, prioritise deliverability. It’s the foundation that everything else depends on.
And remember: you don’t need to do this alone.
At 404 Marketing, we help small businesses simplify their digital marketing, improve performance, and get more from their email strategy. Whether you need help setting up SPF/DKIM/DMARC, choosing the right platform, or improving engagement, we can guide you through it.
