Ask a Deliverability Expert: 25 Ways to Keep Your Newsletter Off Blocklists

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Most email services, like Gmail or Yahoo, use blocklists to decide whether or not emails are legitimate. You can probably guess what blocklists do just from their name: They create lists of email domains and IP addresses that will be kept out of an inbox.

If your newsletter ends up on a blocklist, you might be in real trouble. As I wrote in my guide to blocklists: “If you end up on a blocklist, you may find yourself unable to deliver your emails to your readers. The blocklist effectively tells the inbox, ‘This sender seems shady — send their emails to spam.’”

These blocklists are maintained by companies like Spamhaus, Spamcop, or Barracuda Central, and getting off one isn’t easy. You can submit a removal request to the blocklists, but it takes time to go through that process, and it might take even longer for the inboxes to start to treat your emails as reputable.

The best way to deal with a blocklist? Don’t get on one in the first place.

With that in mind, here are 25 tactics you can use to make sure you stay off blocklists, out of the spam folder, and in the inbox.

1.) Obtain explicit consent from recipients before sending them emails — This means that you should only send emails to individuals who have specifically requested to receive emails from you by signing up for your newsletter. Don’t email users without their permission — period.

2.) Provide a clear and easy way for recipients to unsubscribe from your emails — This allows recipients to opt out of receiving emails from you if they no longer wish to receive them. Some companies try to hide the unsubscribe link, but that’s a mistake. If someone wants to unsubscribe, that’s their right. And remember: If someone can’t find the unsubscribe link and wants to, they might mark your email as spam instead, and that’s far worse for your deliverability than an unsubscribe.

3.) Regularly clean your email list to remove inactive or invalid email addresses — This helps to ensure that you only send emails to active and valid email addresses — a best practice that can improve your deliverability. Here’s a guide that walks through what to send as part of a reactivation campaign and when to send it.

4.) Send relevant and valuable content to your recipients — Blocklists expect senders to provide value to their recipients by sending relevant and useful content that recipients will engage with. They also expect it to match what you usually send subscribers, both in terms of content and frequency. For instance, if you subscribed to a weekly newsletter about cooking, and suddenly, you started getting daily emails about sports gambling, well, that might raise some red flags for a blocklist.

5.) Use a reputable email service provider (ESP) that follows best practices and has a good reputation — Using a reputable ESP can ensure that your emails are delivered and that you maintain a good reputation. Most ESPs have some sort of deliverability team in place to handle best practices, and some — like AWeber or Mailchimp — even maintain their own sending domain to maintain strong deliverability.

6.) Avoid using deceptive subject lines — Blocklists expect senders to be honest and transparent in their email marketing practices. Don’t try to trick readers into opening your newsletter — a subject line like “hey i’m on the zoom” might get opened, but is also far more likely to get your email marked as spam or added to a blocklist.

7.) Be careful with spammy words in your subject line — One more on the note of subject lines. Most senders don’t need to worry too much about spammy words — words like “free,” “guaranteed,” and “earn money” — as long as you use them in the context of your normal newsletters. Sending a single email with the word “free” in the subject line shouldn’t cause an issue (especially if you’re promoting something like a free trial — there aren’t many other ways to say that!). But if you always send emails with these words or use them alongside other spammy behavior, you might get in trouble with blocklists.

8.) Don’t use purchased or rented email lists — Sending emails to individuals who have not explicitly requested to receive emails from you is a violation of most blocklist rules and compliance laws. Don’t buy lists — it’s one of the fastest routes to ending up on a blocklist.

9.) Don’t send emails to individuals who have previously marked your emails as spam — Here’s one that’s as self-explanatory as it gets: A reader who marked your email as spam has clearly indicated that they’re not interested in receiving emails from you. Don’t send them any more emails. Not all email platforms offer good reporting on spam complaints, but a tool like Google Postmaster might help you monitor these.

10.) Utilize verification at the point of sign-up — You can use double opt-in, which requires individuals to confirm their email address before being added to your email list. That can help to reduce the risk of spam complaints. Or if you use single opt-in, add additional levels of protection, like reCAPTCHA or a third-party verification tool, like Kickbox, to keep your list clean. 

If you’re not sure whether to use single or double opt-in, this guide can help you walk through your options.

11.) Don’t use misleading or false information in your emails — Blocklists expect honesty and transparency from senders. Lying to or misleading your subscribers will have consequences. Telling a reader “You’ve won!” and then informing them they’re a big winner because they’re reading this email? That’s always a bad idea.

12.) Don’t use excessive formatting or graphics in your emails — This can make your emails look spammy and can trigger spam filters. A few images in a newsletter isn’t an issue, but an email with dozens (or hundreds) of images might raise some red flags.

13.) Follow the email laws in the places your subscribers live — In the United States, the CAN-SPAM Act is a law that sets requirements for commercial email messages. Other countries and regions have their own laws, like Canada’s Anti-Spam Law (CASL) or Europe’s General Data Protection Regulation (GDPR). Senders are expected to follow the requirements of these laws to avoid being placed on a blocklist.

14.) Don’t use fake or forged headers — When an email is delivered to the inbox, it includes what’s known as a header, which contains information about who sent the email and when. Some spammers try to insert fake headers to get around spam filters, but blocklists will end up catching those who do so. Again, this comes back to basic principles: Be honest and transparent with your audience, and you should be just fine.

15.) Don’t use hidden or invisible text in your emails — This is a common spam tactic and is not allowed by most blocklists. (This should be an easy one to avoid for most senders.)

16.) Don’t send to spam traps — As I wrote about in my guide to understanding blocklists, “Spam traps are email addresses that are specifically set up to catch spam. These are email addresses that blocklists know aren’t real — so if they end up on your list, it’s a signal that you might be engaging in shady practices, like buying emails.” Sending emails to spam traps can result in your IP address or domain being placed on a blocklist. This is where using double opt-in, reCAPTCHA, or a third-party verification tool can help to make sure spam traps don’t end up on your list in the first place.

17.) Don’t send emails in excess of normal sending patterns — Senders are expected to follow normal sending patterns to avoid being flagged as spam. Consistency is key. If you’re making a big change — like switching from a monthly newsletter to a daily newsletter — you may want to start by sending it to your most-engaged users and then grow the list from there.

18.) Don’t use redirecting URLs or shortened links in your emails — Spammers often use link shorteners, like bit.ly, to hide the true destination of the link. Yes, a bit.ly can be nice for tracking the number of clicks on a link, but when you use it in your emails, you’re also raising a red flag for a blocklist.

19.) Don’t send emails with attachments frequently used by malware — This includes file types such as .exe, .vbs, and .bat. If you do happen to be driving readers to download something legitimate, you may want to first send readers to your website and then ask them to download it from there.

20.) Use a consistent sending domain — If you usually send your emails from yourbrand.com, stick with it. Using a consistent sending domain can help to improve your sender reputation and deliverability. If you have to switch domains, make sure readers know about the change and slowly migrate to the new domain. Suddenly sending a high volume of email from a brand new domain might raise a red flag — it’s something a spammer might do. Instead, slowly start to roll out that new domain, first through personal emails, and then in newsletters sent to highly-engaged readers, and then to your whole list.

21.) Use a valid and up-to-date sent-from address — Using a fake or outdated “from” address can trigger spam filters. You should also avoid using noreply@ emails — send your emails from an email address with an inbox that can receive replies from subscribers.

22.) Don’t send to email addresses that consistently bounce — Many ESPs will automatically remove hard bounces for you, but soft bounces (usually resulting from a temporary technical error) might stay on your list. You may want to suppress these users who frequently soft bounce or remove them from your list entirely. A high percentage of bounced or rejected messages is an indication of poor email list quality and can affect your sender reputation.

23.) Authenticate your sender domains and subdomains — Authentication allows you to protect users from spoofed emails and makes it easier for inbox service providers to measure and track the emails you send. Make sure you use the three main sources of authentication: SPF, DKIM, and DMARC. If you need help setting these up, reach out to your ESP — they can help you and make sure you’re properly authenticated.

24.) Don’t send emails designed to harvest personal information — It’s one thing to ask readers to enter their name or email address to win a contest; it’s another to ask for extremely personal information, like a passport or Social Security number. Be careful about what you ask for.

25.) Don’t act like a spammer —  Here’s the simplest rule of all: If you act like a spammer, blocklists will treat you as one. If you send content that’s offensive, inappropriate, doesn’t fit your business, or — and it should really go without saying, but I’ll say it anyway — is illegal, you will probably end up on a blocklist. If you try to trick readers into taking an action in a way that a spammer would, well, you will end up on a blocklist.

Just keep sending good newsletters to readers — the content they expect, at the times they expect — and your emails will land where they belong: in people’s inboxes.

Thanks to our sponsor

The stories you’re reading on inboxcollective.com are made possible thanks to the generous support of our spring sponsor, Litmus. They’re an all-in-one marketing platform that empowers you to build, test, review, and analyze emails more effectively than ever so you can get the most out of every send. Learn why 700,000+ professionals trust Litmus to make every send count.