Introduction

Have you ever sent an important email, only to find out later that it ended up in the recipient’s spam folder? If so, you’re not alone. Email deliverability is a critical factor for businesses, marketers, and professionals who rely on email communication. When emails end up in spam instead of inboxes, it leads to lower engagement, missed opportunities, and potential damage to your sender’s reputation.

Spam filters have become more advanced, using complex algorithms to evaluate email content, sender reputation, and authentication protocols. Even if your emails are legitimate, they can still be flagged as spam due to factors like missing SPF, DKIM, and DMARC records, spammy subject lines, or sending emails to verified lists.

In this guide, we’ll explore common reasons why emails end up in spam and provide 10 expert tips to improve your email deliverability. You’ll learn how to authenticate emails, avoid spam trigger words, use a reputable email service provider, and maintain a clean email list. By following these best practices, you can ensure your emails arrive in the inbox, increase engagement, and protect your sender’s reputation.

Key Takeaways

Understanding Why Emails Go to Spam

• Spam filters analyze email content, sender reputation, and authentication protocols to determine inbox placement.
• Common reasons emails go to spam include missing SPF, DKIM, and DMARC authentication, spammy content, poor sender reputation, and excessive links or attachments.
• Poor email deliverability can reduce engagement, lower conversion rates, and even lead to blocklisting by major email providers.

10 Tips to Stop Emails from Going to Spam

1. Authenticate Your Email – Set up SPF, DKIM, and DMARC to verify sender legitimacy and reduce phishing risks.
2. Use a Reputable Email Service Provider (ESP) – Platforms like Mailchimp, SMTPMaster, and Brevo help maintain a high sender reputation and deliverability.
3. Avoid Spam Trigger Words – Refrain from using terms like “Free,” “Buy Now,” or “Limited Time” that can trigger spam filters.
4. Keep a Clean and Verified Email List – Regularly remove inactive subscribers and use verification tools like ZeroBounce, NeverBounce, and Hunter.io.
5. Encourage Subscribers to allowlist Your Email – Ask recipients to add your email to their safe senders list for better inbox placement.
6. Maintain a Good Text-to-Image Ratio – Follow the 60% text / 40% image rule to avoid spam filter penalties.
7. Personalize Emails for Higher Engagement – Use recipient names, behavior-based segmentation, and dynamic content to increase open rates and trust.
8. Monitor Email Sending Frequency – Avoid sending too many or too few emails, as both can hurt engagement and trigger spam complaints.
9. Use a Clear and Recognizable Sender Name – Ensure your sender name is professional, branded, and easily identifiable.
10. Always Include an Easy Unsubscribe Option – Make it simple and quick for users to opt-out to reduce spam complaints and comply with email regulations.

How to Check If Your Emails Are Going to Spam

• Use free tools like Mail-Tester, GlockApps, MxToolBox, Google Postmaster Tools, and SpamAssassin to analyze email deliverability.
• Track email open rates, spam complaints, and bounce rates with platforms like Mailchimp, SMTPMaster, and Brevo.
• Ensure spam complaint rates stay below 0.1% and open rates remain above 20% for optimal deliverability.

Table of Contents

1. Introduction

2. Key Takeaways

3. Understanding Why Emails Go to Spam

4. 10 Tips to Stop Your Emails From Going to Spam

• Authenticate Your Email With SPF, DKIM, and DMARC
• Use a Reputable Email Service Provider
• Avoid Spam Trigger Words in Subject Lines and Content
• Keep a Clean and Verified Email List
• Encourage Subscribers to allowlist Your Email
• Maintain a Good Text-to-Image Ratio
• Personalize Emails to Increase Engagement
• Monitor Your Email Sending Frequency
• Use a Clear and Recognizable Sender Name
• Always Include a Proper Unsubscribe Option

5. How to Check If Your Emails Are Going to Spam

6. Final Thoughts: Improve Email Deliverability and Reach More Inboxes

Understanding Why Emails Go to Spam

Spam filters use a combination of algorithms, keyword analysis, reputation checks, and user feedback to determine whether an email should be delivered to the inbox or spam folder. They scan emails for suspicious content, excessive use of links, misleading subject lines, and attachments. Filters also check the sender’s reputation, including IP address history and domain authenticity, using protocols like SPF, DKIM, and DMARC to verify legitimacy. If an email fails these checks, it is flagged as spam.

Email deliverability is crucial for businesses relying on email marketing, customer communication, and transactional emails. If emails consistently land in spam folders, businesses face reduced engagement, lower conversion rates, and potential damage to their reputation. Poor deliverability can also lead to blocklisting by major email providers, making it even harder for legitimate messages to reach customers.

Common reasons emails get as spam

1. Lack of Authentication – Not setting up SPF, DKIM, and DMARC records can trigger spam filters.
2. Spammy Content – Excessive use of all caps, misleading subject lines, or overuse of sales words (Ex. “Free,” “Guaranteed”) can mark emails as spam.
3. Low Sender Reputation – If an email sender has a history of spam complaints or high bounce rates, emails may automatically be flagged.
4. Poor List Hygiene – Sending emails to outdated or unengaged recipients increases the chances of spam classification.
5. High Use of Links & Attachments – Emails overloaded with links, shortened URLs or suspicious attachments often trigger spam filters.
6. Unsubscribed or Unsolicited Emails – Sending emails to users who did not opt-in or making it difficult to unsubscribe can result in spam complaints.

10 Tips to Stop Your Emails From Going to Spam

1. Authenticate Your Email With SPF, DKIM, and DMARC

Email authentication protocols help verify that an email is genuinely sent from the domain it claims to represent. Here’s how each protocol works:

(a). SPF (Sender Policy Framework): SPF records specify which mail servers are allowed to send emails on behalf of a domain. If an unauthorized server attempts to send an email, SPF helps email providers detect and block it.

(b). DKIM (DomainKeys Identified Mail): DKIM adds a cryptographic signature to the email header, ensuring that the email content hasn’t been tampered with during transmission. It allows the recipient’s server to verify the sender’s authenticity.

(c). DMARC (Domain-based Message Authentication, Reporting, and Conformance): DMARC builds on SPF and DKIM by providing policies on how to handle authentication failures. It allows domain owners to instruct email providers to reject, quarantine, or allow emails based on authentication results.

Implementing SPF, DKIM, and DMARC improves email deliverability by:-

1. Reducing the Risk of Spoofing & Phishing – These protocols prevent cybercriminals from impersonating your domain, protecting your brand reputation and recipients.
2. Building Trust With Email Providers – When major email services (like Gmail, Outlook, and Yahoo) detect proper authentication, they are more likely to deliver emails to inboxes rather than spam folders.
3. Improving Sender Reputation – Proper authentication signals that you are a legitimate sender, reducing bounce rates and increasing email engagement.
4. Providing Visibility & Control – DMARC reports offer insights into email performance, helping businesses monitor unauthorized email activity and improve security measures.

2. Use a Reputable Email Service Provider

An Email Service Provider (ESP) plays a crucial role in ensuring emails are delivered successfully and not flagged as spam. ESPs manage the technical aspects of email sending, such as IP reputation, email authentication (SPF, DKIM, DMARC), bounce handling, and spam complaint monitoring. A reputable ESP maintains high sender scores, ensuring that emails sent through their platform are trusted by email providers like Gmail, Outlook, SMTPMaster, and Yahoo.

Using an unreliable or blocklisted ESP can severely harm your email reputation, leading to high spam rates and lower engagement.

Selecting a reputable ESP is essential for optimizing email deliverability. Look for providers that offer:

• Dedicated IPs or high-quality shared IPs to maintain a strong sender reputation.
• Built-in email authentication (SPF, DKIM, DMARC) for enhanced security.
• Advanced spam filter testing to check email content before sending.
• Detailed analytics and reporting to track open rates, click-through rates, and spam complaints.

Recommended ESPs for Reliable Email Deliverability

Here are some trusted email service providers that enhance email reputation and deliverability:

• Mailchimp – A popular choice for businesses, offering automated email campaigns, list segmentation, and spam testing.
• SMTPMaster – Provides Affordable Pricing, Reliable email delivery, and excellent Dedicated support.
• Brevo (formerly Sendinblue) – A cost-effective option with robust email marketing tools, transactional email support, and strong email authentication protocols.

By choosing a trusted ESP, businesses can improve their email deliverability, maintain sender reputation, and ensure their emails land in inboxes instead of spam folders.

3. Avoid Spam Trigger Words in Subject Lines and Content

Examples of Words That Trigger Spam Filters

Spam filters scan email subject lines and content for certain trigger words commonly used in fraudulent, misleading, or overly promotional emails. Using these words excessively increases the chances of emails being marked as spam.

Some common spam trigger words include:

(a). Financial & Urgency-Related Words (e.g. 100% Free, Risk-Free, Limited Time)
(b). Sales & Promotional Words(e.g.Buy Now,Discount,Big Savings)

(c). Scam-Related Words (e.g.Winner, You have been selected, Free Gift)

Emails with too many capital letters, excessive punctuation (!!!, $$$), or suspicious links also raise red flags for spam filters.

To improve email deliverability and avoid spam filters, follow these best practices:

1. Be Clear & Honest – Avoid confusing phrases like “You won!” if the recipient didn’t enter a contest.
2. Personalize When Possible – Using the recipient’s name or other details increases engagement. Example: “John, your exclusive offer awaits!”
3. Keep It Concise – Subject lines under 50 characters perform better and are less likely to be flagged.
4. Avoid Excessive Capitalization & Punctuation –Instead of “Buy Now!!!” use “Special Offer Inside” in a natural tone.
5. Test Your Emails Before Sending –Use email marketing tools to test how your subject lines and content perform against spam filters.

4. Keep a Clean and Verified Email List

Sending emails to invalid, inactive, or uncontrolled addresses can seriously damage your sender’s reputation. Here’s why:

• Increased Bounce Rates – When emails are sent to non-existent addresses, they “bounce back,” signalling to email providers that your list is outdated or poorly maintained.
• Higher Spam Complaints – If recipients mark your emails as spam due to lack of engagement or irrelevant content, email providers may start filtering all your emails into the spam folder.
• Lower Open Rates & Engagement – A cluttered email list with unverified contacts leads to poor email performance, reducing campaign effectiveness.
• Risk of Being Blocklisted – Repeatedly sending emails to invalid or inactive addresses can result in your domain being blocklisted, preventing future emails from reaching your inbox.

To maintain email list hygiene and avoid spam traps, use these tools to clean and verify contacts:

1. ZeroBounce –Detects invalid, fake, and temporary email addresses while removing spam traps.
2. NeverBounce – Provides real-time email verification, helping businesses reduce bounce rates.
3. Hunter.io – Verify email addresses before sending, ensuring high deliverability.
4. BriteVerify – Simple and effective tool for bulk email list verification.

Best Practices for a Clean Email List

• Use Double Opt-In – Customers will need to confirm their email address before being added to your list.
• Remove Inactive Subscribers – Regularly purge emails that haven’t been engaged in 3-6 months.
• Monitor Email Performance – Track bounce rates, open rates, and spam complaints to identify potential problems.

By maintaining a clean and verified email list, businesses can increase sender reputation, improve email deliverability, and increase engagement with their audience.

5. Encourage Subscribers to Allowlist Your Email

What Is Allowlisting and Why It Matters?

Allowlisting is the process of adding an email address to a recipient’s safe senders list, ensuring that future emails from that sender go straight to the inbox instead of the spam folder.

Why is allowlisting important?

• Improves Email Deliverability –Emails are more likely to reach the inbox instead of spam.
• Boosts Open and Engagement Rates – When emails arrive in the inbox, customers are more likely to see them and engage with them.
• Reduces the Risk of Being Marked as Spam – Encouraging recipients to allowlist your emails prevents email providers from mistakenly flagging messages as spam.

Encouraging subscribers to allowlist your email can be done in several ways:

1.Include a allowlisting Request in the Welcome Email

Example: “To ensure you don’t miss any important updates from us, please add [your email] to your safe senders list.”

2. Provide Step-by-Step Instructions

Different email providers have different methods for allowlisting. Provide simple instructions for Gmail, Outlook, Yahoo, and Apple Mail.

Example:

Gmail: Open the email → Click the three dots → Select “Add to contacts.”

Outlook: Open the email → Click “Junk” → Select “Never block the sender.”

3. Use a Friendly Call-to-Action

Instead of a generic request, personalize the ask.

Example:

“Enjoying our emails? Make sure they always land in your inbox by adding us to your safe sender list!”

4. Add a Footer Message in All Emails

Include a reminder in every email footer:

Example:
“Not seeing our emails? Move us to your inbox and add [your email] to your contacts!”

By encouraging customers to allowlist their emails, businesses can improve deliverability, maintain strong engagement, and ensure that important messages are seen.

6. Maintain a Good Text-to-Image Ratio

Why Too Many Images Can Trigger Spam Filters

Email providers use image-to-text ratio as a key factor in spam filtering. Emails with too many images and little to no text are often flagged as spam. Here’s why:

• Spam Filters Can’t Read Images – Since filters primarily analyze text, an email with mostly images and minimal text appears suspicious..
• Hidden Malicious Content – Spammers often hide phishing links inside images, with email providers considering image-heavy emails as a potential threat..
• Slow Loading Times – Some recipients may have images blocked by default, resulting in a poor user experience and reduced engagement.
• Higher Spam Scores – Emails with too many images and little readable text are often penalized by spam filters, which affects deliverability.

To ensure optimal email deliverability, follow these best practices for text-to-image ratio:

1. Follow the 60/40 Rule – Aim for 60% text and 40% images to maintain balance..
2. Always Include Alt Text – Use descriptive alt text for images so that recipients with blocked images can still understand the content.
3. Avoid Using a Single Large Image – Emails with just one large image and no supporting text are more likely to be filtered as spam.
4. Use Well-Formatted, Readable Text – Ensure your email has clear, concise, and engaging text alongside visuals.
5. Optimize Image Sizes – Compress images to reduce loading time and improve user experience.

7. Personalize Your Emails to Increase Engagement

Personalized emails create a better user experience, making recipients more likely to engage and less likely to mark emails as spam. Here’s why personalization helps:

• Increases Open and Click Rates – Emails with personalized subject lines and content are more relevant, which leads to higher engagement.
• Reduces Spam Complaints – Generic, mass emails often feel like spam. When recipients see their name or relevant content, they are less likely to report the email..
• Builds Trust and Loyalty – Personalized content shows recipients that emails are tailored to their interests, making them more likely to subscribe..

Dynamic content allows you to customize emails for each recipient based on their preferences, behavior, and demographics.

Effective personalization strategies include

1. Use the Recipient’s Name – Instead of “Dear Customer,” say “Hi John,” to create a friendly, personal tone.
2. Segment Your Email List – Group subscribers based on interests, purchase history, or engagement level to send targeted emails.
3. Recommend Personalized Offers – Suggest products or content based on past interactions. Example: “John, here are some new arrivals based on your last purchase.”
4. Send Behavior-Based Emails –

• Welcome Emails: After sign-up, send a personalized greeting.
• Cart Abandonment Emails: Remind users of items left in their cart.
• Re-engagement Emails: If a user hasn’t opened an email in a while, send a “We Miss You” message with tailored offers.

1. A/B Test Different Personalization Tactics – Experiment with subject lines, greetings, and content variations to see what drives engagement.

8. Monitor Your Email Sending Frequency

Finding the right balance in email frequency is crucial to maintaining high engagement and low spam complaints.

Sending Too Many Emails

• Increases the risk of annoying customers, resulting in more unsubscribes and spam complaints.
• Spam can trigger filters, especially if recipients start ignoring or deleting emails without opening them.
• Email fatigue can occur, causing recipients to become disengaged from your content.

Sending Too Few Emails

• Reduces brand visibility, making recipients forget why they subscribed in the first place.
• Increases the chances of being flagged as spam when emails are finally sent, as recipients may no longer recognize the sender.
• Low engagement rates, can harm email deliverability and sender reputation.

Set Clear Expectations – Let subscribers know how often they’ll hear from you (e.g., “We send weekly updates and special offers”).

Follow Industry Standards –

• Newsletters & Promotions: 1–3 emails per week.
• Transactional emails (order confirmations, receipts, etc.): Sent immediately.
• Re-engagement emails: Every few months for inactive users.

Allow Subscribers to Choose Frequency – Offer options like daily, weekly, or monthly updates to prevent unsubscribes.

Monitor Engagement Metrics – Track open rates, click-through rates, and spam complaints to determine the optimal frequency.

Use Automation to Space Out Emails – Avoid sending multiple emails in a short period of time by scheduling messages strategically.

9. Use a Clear and Recognizable Sender Name

Your sender name plays a crucial role in email deliverability and engagement. When recipients see an unfamiliar or misleading sender name, they are more likely to:

• Ignore the email – If they don’t recognize the sender, they might assume it’s unimportant.
• Mark it as spam – Suspicious sender names can raise red flags and increase spam complaints.
• Harm sender reputation – A high spam complaint rate can damage your domain’s reputation, making it harder for future emails to reach inboxes.

A recognizable sender name builds trust, increases open rates, and reduces the risk of being flagged as spam.

Use a Consistent, Branded Name – Instead of a generic address like noreply@company.com, use [Your Name] from [Brand] or support@brand.com.

• Example: “Emma from TechSolutions” instead of “marketing123@mail.com”.

Avoid Random or Spammy Words – Names like “Big Sales Today” or “Free Gift Inside” can trigger spam filters.

Keep It Professional – If sending from a personal address, ensure it reflects your brand identity.

Match the Sender Name With Your Email Content – If the email is customer support-related, use support@yourdomain.com instead of a marketing alias.

Test and Monitor Performance – A/B test different sender names to see which ones increase open rates and trust.

10. Always Include a Proper Unsubscribe Option

Failing to provide a clear and accessible unsubscribe option can severely impact your email deliverability and sender reputation. Here’s why:

• Increased Spam Complaints – When recipients can’t find an easy way to opt out, they may mark the email as spam, hurting your sender reputation.
• Legal Violations – Many countries enforce email regulations such as the CAN-SPAM Act (USA), GDPR (EU), and CASL (Canada), requiring an unsubscribe option in marketing emails.
• Damage to Brand Reputation – Forcing people to stay on your list creates frustration and distrust, leading to negative brand perception.

Make the Unsubscribe Link Visible – Place it in the footer of the email with clear wording like “Unsubscribe” or “Manage Email Preferences” instead of hiding it in small text.

Use One-Click Unsubscribes – A complicated opt-out process discourages users and increases spam complaints. Allow users to unsubscribe with a single click.

Offer Subscription Preferences – Instead of losing subscribers completely, provide options to receive fewer emails or select specific content types. Example:

• “Want fewer emails? Switch to our monthly updates instead.”

Confirm Unsubscription Without Hassle – After unsubscribing, display a confirmation message rather than making users log in or fill out a survey.

Honor Requests Immediately – The CAN-SPAM Act requires businesses to process unsubscribe requests within 10 days, but doing it instantly is best for user experience.

How to Check if Your Emails Are Going to Spam

Ensuring that your emails are reaching the recipient’s inbox instead of the spam folder is crucial for engagement and conversions. If your emails are frequently landing in spam, it could be due to a poor sender reputation, spam trigger words, or improper email authentication. Here’s how you can check if your emails are being marked as spam and how to fix the problem.

There are several free tools available to analyze your email deliverability and identify potential spam issues:

1. Mail-Checker – Provides a free spam score by analyzing email content, SPF, DKIM, and DMARC records.
2. GlockApps – Simulates email delivery across different email providers and checks whether it is spam, inbox, or blocked.
3. MxToolBox – Checks blocklists, SPF, DKIM, and DMARC authentication for email domains.
4. Google Postmaster Tools – Provides insights into domain reputation, spam rates, and email authentication performance.
5. SpamAssassin – A popular spam filter that assigns a score based on content analysis and spam rules.

These tools help diagnose deliverability issues and suggest improvements to ensure better inbox placement.

Monitoring email open rates and spam complaints can help determine if your emails are being flagged as spam. Here’s how to analyze these metrics:

• Use Email Marketing Platforms: Services like Mailchimp, SMTPMaster, and Brevo provide insights into open rates, click-through rates, and spam complaints.
• Check Spam Complaint Rate: A spam complaint rate higher than 0.1% (1 complaint per 1,000 emails) can hurt your sender’s reputation.
• Monitor Open Rates: A significant drop in open rates may indicate emails are landing in spam. Aim for an open rate above 20% for healthy engagement.
• Authenticate Emails: Ensure SPF, DKIM, and DMARC records are correctly set up to prevent spoofing and improve credibility.
• Avoid Spam Trigger Words: Words like “free,” “urgent,” “guaranteed,” and “win” in subject lines can increase spam probability.

Final Thoughts: Improve Email Deliverability and Reach More Inboxes

Ensuring that your emails land in the inbox rather than the spam folder is essential for successful communication and marketing. By following best practices and leveraging the right tools, you can significantly improve your email deliverability.

Improving email deliverability takes consistent effort, but the rewards are worth it—higher engagement, better brand reputation, and increased conversions. Start by testing your emails with a free deliverability tool, optimizing your content, and maintaining good sending habits. By making these small but effective changes, you can ensure that your emails reach more inboxes and drive greater campaign success.

Take action today and optimize your email strategy for better results! 🚀

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