Spam filters protect email service provider (ESP) end-users from malicious content and cyberattacks. Occasionally, they also doom well-meaning senders to the “Junk” folder.
One step to avoid spam filters is to ask your subscribers to allowlist your domain.
In this article, we’ll cover what allowlisting is and its benefits. We’ll also walk you through how users can allowlist your domain so your emails always land in their inboxes.
What is allowlisting?
Email allowlisting is the process of adding an email address to a contact list so it’s marked as an approved sender. Doing so gives your domain a digital signature that circumvents filtering systems and email blockers, so your emails don’t end up in the spam folder.
According to Mailgun’s State of Email Deliverability 2025, 48% of senders say staying out of the spam folder is a top challenge. Allowlisting is the first step in overcoming it.
An allowlist is the opposite of a denylist (also referred to as a blocklist), which flags an incoming email as potentially harmful.
If an ESP treats your emails like those on a blocklist, your recipients may miss your message altogether.
How does allowlisting work?
Emails from unknown or blocklisted addresses get caught in a spam filter and are directed to the junk folder. These emails often contain malicious code or harmful material that can exploit device vulnerabilities. Examples include phishing scams, ransomware, malware and spoofing links.
When a customer allowlists your email address, every email you send bypasses the filters and reaches their inbox. Allowlisting your brand notifies the system that your emails are safe and the subscriber wants to receive them.
For example, Gmail filters emails away from the “Primary” folder to spam folders. The ESP also filters emails to “Social” and “Promotional” inboxes, driving your email away from the target: your lead or customer’s most-used inbox. Getting them to allowlist your email address ensures your emails arrive in their “Primary” inbox.
Note: Being allowlisted doesn’t give you free license to send email blasts with no inherent value for the reader. Instead, you want to ensure you use the opportunity to build trust and nurture customers.
For example, you can build trust by providing valuable content and demonstrating compliance with regulations like the CAN-SPAM Act. Emails that comply will avoid misleading subject lines, make ads clear and give unsubscribe options.
What are the benefits of allowlisting?
Getting subscribers to allowlist your emails gives your campaigns as close to a guarantee of being seen as possible. Here’s how the benefits of allowlisting affect your emails:
Improved email deliverability. Your emails will arrive in inboxes more often, so more people will see them. Over time, it will improve the deliverability of your entire list of emails.
Better subscriber relationships. When recipients see your messages more often, they’re more likely to form a relationship with your brand.
Improved email engagement metrics. More people receiving your emails means more eyeballs on your content, helping improve metrics such as open rates and, hopefully, sales.
To get allowlisted, you’ll most likely need to ask your recipients to take a few additional steps after signing up for your email list.
Think of it like a CTA, but instead of asking for a sale or a click-through, you’re asking readers to add you to their contact list.
How to get subscribers to allowlist you: allowlisting best practices
The best way to get your address allowlisted is to ask subscribers to add it to their contact list.
It doesn’t need to be a big ask or a separate email. You can even include it in your automation process, such as in your “Thank you for subscribing” email.
Here’s an example of what this can look like:
Thanks for signing up for my weekly newsletter! To make sure you receive all my emails, discounts and special offers, add this email address to your contacts list.
Edit your message to fit your tone of voice. Use a conversational approach so recipients feel like they’re adding a friend to their contacts instead of a business.
Here’s another example. This fun spin is from Anne Handley from Marketing Profs:
Alongside a dash of humor, she includes clear instructions on how to allowlist her emails. She keeps the instructions simple to avoid confusing her audience and includes the benefits of allowlisting her emails.
Keep your allowlisting instructions simple. If you want to give readers more in-depth instructions, you could link them to a knowledge base with instructions or troubleshooting tips.
Here are some more allowlisting tips:
Provide value to your subscribers. People won’t want to allowlist your emails if you never say anything interesting or useful.
Keep your instructions short. The longer your instructions are, the less likely subscribers will be to read them. There’s no need for complex cybersecurity or data protection explanations that will be meaningless to most people.
Conduct a DNS health check. DNS, or domain name systems, convert IP addresses into readable domain names. A DNS health check ensures your emails are delivered and offers security benefits.
The most important thing to remember regarding allowlisting is to provide quality emails that your readers want to receive.
How can a subscriber allowlist your email address?
If you plan on creating an allowlisting guide for your subscribers, here is some information for two popular ESPs and their mobile device equivalents to get you started.
How to allowlist an email address with Gmail
There are two easy ways to add a contact in Gmail.
Hover over the sender’s name in the message list or within the email, then click the “Add to contacts” icon.
2. Go to the Contacts app within Google Apps, then click “Create a contact”.
If your emails have previously been sent to the spam folder, you’ll want readers to mark them as “Not spam”.
To do this, they need to go to one of your emails in their spam folder, right-click on it and select “Not spam”.
How to allowlist an email in the Gmail app
On a mobile device, users can open the email, hover over the sender’s name and click “Add to contacts”.
If the email has already gone to the spam folder, they should open the app and go to the Spam or Junk folder.
Select a message from the sender they want to add to an allowlist, then click “Report not spam”.
How to allowlist an email address with Outlook.com
For Microsoft email addresses, such as those on Outlook.com, Windows Live Mail, Hotmail and MSN Mail, your subscriber needs to sign in to their account and add you to their contacts using the following steps.
How to add a contact in Outlook.com
Subscribers must hover over the name in the email preview window and click “Add to Outlook Contacts”.
They can also manually add the sender’s email address to their Outlook Contacts to send all future emails to their primary inbox.
How to add an address to Safe Senders in Outlook.com
The Safe Senders list tells Microsoft your subscriber trusts your emails. To enable this option:
Go to Settings
Click on “Junk”
Find the “Security options” tab and check the box that says “Trust email from my contacts”
Users can add email addresses (“[email protected]”) or domain URLs (“@domain.com”) under the same “Junk” folder settings. They can simultaneously add multiple email addresses or URLs to the Safe Senders list.
How to allowlist an email on the Outlook app
On a mobile device, users need to open the Outlook app, then open an email from the sender they want to add to their allowlist.
Click the three dots at the top right, then select “Move to Focused Inbox” followed by “Always Move”.
