Avoid spams words in your email subject lines to improve email deliverability

You might be surprised to learn that the subject line of an e-mail is actually quite important. It’s your first chance to make a good impression on people who will read your email and on the spam filters that might block it. If your subject line looks like spam, your email will end up in the junk folder, even if the content is great.
Don’t worry! With a few tips and a good understanding of spam words, you can increase your chances of reaching the inbox. In this article, we’ll show you how to avoid these mistakes and optimize your email subject lines like a pro.

What makes your email subject important for email deliverability?

Your email subject line is the first thing your recipients see. It’s also the first thing spam filters look at. These filters are getting better and better at protecting users from unwanted messages. They look at every word, every punctuation mark, and even the tone of your message. If you use words that are too common in spam or come across as too pushy, your email might get caught by a filter and end up in the spam folder.

At MailSoar, experts in email deliverability, we know how essential mastering this aspect is to the success of your campaigns. We help our customers refine their email subject lines to avoid detection by these filters and improve their open rates.

What does “optimizing your email subject lines” mean?

Optimizing your email subject lines means choosing relevant, attractive keywords and avoiding spam words to encourage recipients to open your emails.

How do spam filters for email subject lines work?

What exactly are spam words? Why are they important?

Spam filters use a few different factors to decide whether or not an email is legit. One of the main things that spam filters look for are what are called ‘spam words’. These are words or phrases that get thrown around in spam like “Free, “Click here,” and “Special offer.” Using too many capital letters, exclamation marks, or an overly promotional tone can also set off these spam filters.

These words are like red flags for email providers. They’re often linked to phishing or spam attempts. Even if your message is legit, using these email spam trigger words can put it in the spam folder, which can hurt your visibility and impact.

List of spam trigger words to avoid in your email subject

To help you identify spammy terms to avoid, here is a list of spam words classified by theme:

Promotions and special offers.

Free
Exclusive promotion
Limited offer
Exceptional discount
Special discount
Best price
Free bonus

Urgency and incitement to action

Opportunities and new developments.

Financial terms and investment.

Exaggerated guarantees and promises.

Safety and alerts

Using these trigger words in your objects can arouse the suspicions of spam filters. It’s best to replace them with more subtle, authentic formulations.

How to optimize your email subject lines to improve deliverability

There’s more to optimizing your email marketing than avoiding spam words. You also need to find the right balance between grabbing your recipients’ attention and staying authentic. Here are a few tips to help you achieve this:

Be clear and relevant: If you're specific about what you're talking about and it's related to the email's content, it'll help your recipients understand what you're saying and make them more confident in what you're sending.
Customize your objects: If you include the recipient's first name or other specific info, you'll get better open rates and build a stronger connection with your audience.
Stay concise: If your message is too long, it might get cut off in someone's inbox. Try to keep your subject line to 40-50 characters so they don't get cut off in the inbox.
Adopt a friendly tone: Use friendly, professional language. Try to avoid using overly commercial or aggressive language.
Avoid excessive punctuation and capitalization: If you use too many capital letters or exclamation marks, filters and recipients might think you're being aggressive.

Need help optimizing your email campaigns?

At MailSoar, our experts are here to help you improve your deliverability. Contact us to find out more.

Are there alternatives to spam words in email subject lines?

Yes, you can use more neutral, informative terms in your email subject lines to avoid being marked as spam. Try using phrases like “New collection available” or “Important update.” This will get people’s attention without risking being marked as spam.

Examples of optimized objects with alternatives to spam words

To illustrate these tips, here are some examples of optimized email subject lines in different themes:

Instead of:

Try:

E-commerce / Online sales

BUY NOW AND SAVE 50% OFF

Our best personalized offers are waiting for you

Events / Seminars

CONFIRM YOUR PARTICIPATION NOW

Join us for an exclusive event this month

Finance / Banking

IMMEDIATE CREDIT AVAILABLE AT 0% INTEREST

Discover our financing solutions tailored to your projects

SaaS / Tech services

TRY OUR SOLUTION FREE FOR 30 DAYS

How to optimize your productivity with our new platform

Health / Wellness

LOSE WEIGHT FAST WITH THIS MIRACLE METHOD

Our tips for a healthier everyday life

Vacations / Leisure

BOOK YOUR DREAM VACATION NOW AT A REDUCED PRICE

Our tips for a healthier everyday life

By adapting your objects in this way, you avoid spam words while remaining attractive to your recipients.

Tips from our experts on how to avoid email spam filters

Here are a few more tips to avoid the spam folder:

Use natural language: Avoid over-selling or over-promising. Instead, use authentic language that really reflects what you’re offering.
Test your objects: Before sending your campaign, A/B test it to see which subject line works best with your audience.
Monitor your sender reputation: Spam filters take into account your sending history. A good reputation improves your deliverability.
Segment your subscriber list: Send relevant messages to specific segments to increase engagement and reduce unsubscribes or reports of spam.
Include a clear unsubscribe option: This shows you respect your recipients and reduces the risk of being reported as spam.

How do I know if my email subject lines are effective?

You can see how well your email subject lines are doing by checking how many people open your emails. If a lot of people are opening them, it’s a good sign that your subject lines are doing their job. Find out more about the different KPIs you need to monitor to optimize your emails in our dedicated article.

Making your email subject lines as effective as possible is a great way to improve how many people see your messages and make sure your campaigns have the biggest impact. If you steer clear of spam words and think strategically, you’ll have a better chance of reaching your recipients and getting them to engage.

At MailSoar, we’re passionate about email deliverability. We’re here to help you navigate this complex field. If you’d like personalized support or a complete audit of your emailing strategy, please don’t hesitate to contact us. Together, we’ll take your emails to new horizons!