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What’s a spam checker, and what are its 5 benefits?

What are spam checkers, and how they can make your email development workflow easier? Here’s everything you need to know about why emails go to spam and what you can do about keeping your emails out of the spam folder.



Integrating email into an app isn’t as simple as just adding an email functionality. You also have to consider email deliverability issues, email marketing metrics like open rates, and accessibility. After all, what if your emails land in the spam folder instead of your user’s inbox? You might as well have not sent out an email in the first place.

We’ll go over what spam checkers are and how they can make your email development workflow easier. Then, we discuss what to look for when choosing a spam checker.

What is a spam checker?

According to Statista, email spam makes up nearly 40% of all email traffic. Imagine how annoying this is for your users since spam messages might contain malware, phishing attacks, and other scams. For an email sender, this is also bad news because it means email clients and blocklist vendors are dialed in to potentially spammy content. Even if you’re sending out a legitimate email, you might end up in the spam folder.

Wouldn’t it be nice to know if your email might be flagged as spam before you hit send?

That’s where spam checkers come in. A spam checker gauges how spam filters might assess your email and whether it will land in the spam folder or your user’s inbox. We’ll dive deeper into the “how” of all of this below.

Why do emails go to spam?

It’s annoying to have your emails land in spam. Here are some common reasons why that might have happened.

  • You’re sending spammy content, or content that looks spammy: Spam filters often look identify spam by looking for excessive use of exclamation points, capitalization, images, or oddly phrased language.

  • Too many of your subscribers mark your emails as spam: If your reader can’t find an easy way to unsubscribe from your emails, they might mark your messages as spam. Too many abuse complaints can land you in the spam folder or on a blocklist.

  • You have low email engagement rates: ISPs often look at engagement rates — that is, how much time readers spend on your emails — to determine whether or not your emails are wanted messages. If your readers delete your emails without opening them, this could send a red flag to email clients.

  • Your IP reputation or sender reputation is bad: You may have damaged your IP or sender reputation by sending out high volumes of email without warming up your IP address, by having a high bounce rate, or because your subscribers mark your messages as spam. If you’re using a shared IP address, one of the other users on the IP address may be sending out spammy messages, damaging your IP reputation. ISPs use your sender reputation in determining if your message gets access to the inbox.

4 best practices to avoid getting caught by spam filters

Staying out of the spam folder is a combination of different factors, but here are four best practices to avoid getting labeled as spam:

  • Don’t look like spam: Avoid using too many exclamation points, all-image emails, and excessive or random capitalization. If your email is legitimate, don’t let an email spam filter think it looks like spam.

  • Give your subscribers an easy way to unsubscribe: If your readers can’t find an easy way to opt out of your emails, they might mark your emails as spam. This is a red flag for ISPs who are wondering if your email messages are spam.

  • Have proper authentication protocols in place: Ensure you have your SPF records, DMARC, DKIM, and BIMI records in place. These are like your identity cards, verifying that you are who you say you are. ISPs check for these authentication records to ensure email messages come from proper email senders.

  • Maintain your mailing list hygiene. Verify and validate the email addresses on your email list so that you can keep your bounce rates low and your email delivery rate high. After all, you don’t want to land in a spam trap.

What are the 5 benefits of using spam checkers?

Let’s say you’ve done your best to avoid producing spammy email content and to keep your deliverability rate up. But what if your legitimate message is still marked as spam? Use a spam checker before sending to get some peace of mind.

Some benefits of using spam checkers include:

  • They improve your sender reputation by ensuring your emails have a higher placement rate in your reader’s inbox.

  • They improve your email deliverability by making email clients more likely to place your emails in the inbox when you do send them. In other words, by seeing how your email will perform, you potentially lower the rate of bounced emails.

  • They improve the quality of your email. Worried your legitimate email looks spammy? Spam checkers let you know what spam filters think about your email.

How do spam checkers work?

Spam checkers obviously work, but how exactly do they work? Black magic? Not quite.

Not all spam checkers “work” in the same way, but there are a few methods spam checkers use to check your email’s inbox placement.

  • They might try to place your test email: Spam checkers might ask you to send your email to a test email address. Then, they try to place your email with a number of email clients, including Gmail, Microsoft Outlook, and Yahoo Mail.

  • They might run your email through spam filters: After you upload or send a test email to a spam checker, they might run your email through spam filters like SpamAssassin.

  • They might check if your email is blocklisted: Spam checkers might run your sending email domain against major blocklist service vendors to make sure your sending domain isn’t blocklisted.

  • Analyze your email to check for spammy words: That’s right, don’t leave it up to chance. Spam checkers validate your links and content to make sure they don’t look spammy to a spam filter.

  • Verify your authentication records: Some spam checkers might help you check if you’ve properly set up your authentication records.

What should I look for when choosing a spam checker?

While spam checkers all work the same way to some extent, they’re not all created equal.

When looking for a spam checker, here are three things to keep in mind:

  1. Cost: There are some great free spam checkers out there, like Mailgun’s Inbox Placement tool. On the other hand, there are also some not-so-great ones. Keep cost in mind, but don’t let it stop you from trying out a free-to-use tool.

  2. Effectiveness: Does your chosen spam checker have a good track record for “getting it right?” That is, are they effective at predicting your inbox placement? Don’t leave your deliverability up to chance.

  3. Extra features: Does your spam checker verify your authentication protocols? Do they give you feedback on potentially spammy-looking content? Don’t overlook the “extras.”

Wrapping up

Inbox, here we come! Hopefully, we’ve given you some tips on using spam checkers and avoiding the spam folder. If you’re interested in Mailgun’s spam checker reach out to us for more information. Not only do we have great tools, we have a great team focussed entirely on your deliverability.

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