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How an Email Spam Checker Helps in Increasing Deliverability

Don't let spam derail your email campaigns. Use an email spam checker to ensure your messages hit the inbox every time.
Written by
Vikas Jha
Published on
January 18, 2024

Mastering Email Deliverability with an Email Spam Checker

Email deliverability isn't just a buzzword; it's the backbone of effective digital communication.

In fact, according to data, nearly 21% of legitimate emails never reach the inbox.

That's a lot of missed opportunities, wouldn't you agree?

Spam Checkers are tools that help you evaluate your emails against common spam filters, DNS records, and even your sending reputation to give you a spam score.

The lower the score, the higher your message has chance of hitting the inbox. Simple, yet profoundly impactful.

The Anatomy of an Email Spam Checker and Spam Test

What Will Be Tested in an Email Spam Test?

An email spam test tool evaluates various elements like your sending IP address, DNS records, and even common spam filters to predict where your email will land.

What is a Spam Score?

A spam score is a numerical value assigned to your email based on various factors like spam words, sender reputation, and HTML code.

Understanding Your Spam Score

Here's a quick rundown of factors influencing your spam score.

  • Email Content: Keywords and phrases that are commonly flagged by spam filters.
  • Sender Reputation: The trustworthiness of your sending IP and domain.
  • HTML Formatting: Poorly coded HTML can trigger spam alerts.
  • Subject Line: Certain words or excessive punctuation can raise red flags.
  • Sending Frequency: Too many emails in a short time can be a spam indicator.
  • User Engagement: How recipients interact with your email, such as open and click rates.
  • DNS Records: Proper setup of SPF, DKIM, and DMARC records.
  • Blacklists: Whether your IP or domain is on any email blacklists.
  • Attachments: Type and size can affect spam score.
  • Email Service Provider: The reputation of the service you're using to send emails.

How Common Spam Filters Operate

Here's how common spam filters generally operate:

  • Keyword Analysis: Scan for known spam words in the subject line and email body.
  • Header Inspection: Examine email headers for inconsistencies or misleading information.
  • Sender Reputation: Check the sending IP and domain against blacklists and reputation databases.
  • Content Filtering: Evaluate the email content for spam-like characteristics, such as excessive use of capital letters or links.
  • User Behavior: Monitor how recipients interact with emails from the sender, including open rates and whether emails are marked as spam.
  • SPF, DKIM, and DMARC Verification: Validate the sender's identity through these authentication protocols.
  • Machine Learning: Use algorithms to identify new spam patterns based on user behavior and feedback loops.

How to Use an Email Spam Checker

Using an email spam checker can be the difference between your email landing in the inbox or the spam folder. Here's a quick guide on how to use one:

  • Select Tool: Choose an email spam checker that fits your needs, whether a free or paid service.
  • Input Email: Copy and paste your email content into the tool, including the subject line and HTML code.
  • Run Test on a regular basis: Initiate the spam test, which will analyze various elements like spam words, sender reputation, and HTML structure.
  • Review Score: Examine the spam score provided, which indicates the likelihood of your email being marked as spam.
  • Check Recommendations: Follow the tool's suggestions for lowering your spam score, such as modifying the subject line or content.
  • Test Authentication: Ensure your SPF, DKIM, and DMARC records are set up correctly.
  • Adjustments: Edit your email based on the feedback and run another test to see if the score improves.
  • Finalize: Once you achieve a satisfactory spam score, you're ready to send your email.

List of Recommended Spam Checker Tools

List of Recommended Spam Checker Tools

Navigating the world of email deliverability can be a bit of a maze. But don't fret; there are several reliable spam checker tools to guide you. Here's a quick rundown:

1. GlockApps

This tool offers real-time delivery results and evaluates your sender IP address reputation, SPF, and DKIM records. While it offers a free trial for up to three spam tests, you'll need to switch to a paid plan for continued use.

2. IsNotSpam

If you're on a budget, this could be your go-to. IsNotSpam provides an in-depth report on your newsletter content, performing checks like SPF, SKIM, and SpamAssassin. And the best part? It's free.


Litmus helps you find out if your server is blacklisted and offers a dashboard analytic tool to clean up your emails. Note that this is a paid service.

4. Mtoolbox

This tool offers monitoring and lookup solutions, alerting you when there's a change in your email reputation. Free users get one monitor, while paid users enjoy more advanced features.


Ideal for those who want a quick final check, this tool offers a simple spam score checker and other important MOZ metrics.

6. Spamanalyse

A free, straightforward tool that helps you check if your email newsletter is spam filter-friendly. Just copy, paste, and submit.

7. Spam Check by Postmark

This free instant checker evaluates the spam score of your email messages. Just paste your copy, including the header, to get your score.

8. UltraTools

This tool offers a complete set of free DNS and domain tools to test your online hosting environment, including DNSSEC and IPv6 details.

9. Blacklist Check

This tool evaluates your mail server IP address against over 100 DNS-based email blacklists. It's crucial to ensure your emails reach their destination.

So, whether you're a seasoned email marketer or just getting started, these tools can help you ensure your emails land where they should—in the inbox, not the spam folder.

The Role of Sending IP and IP Addresses on Spam Score

Your sending IP isn't just a bunch of numbers; it's your email's passport to the inbox world.

A tarnished sending IP can make your emails unwelcome in inboxes.

Your sending IP and IP addresses are critical to your email deliverability.

Here's how they impact your email campaigns:

  • Reputation Tracking: Your sending IP accumulates a reputation score based on your email activity. A poor score can lead to your emails being marked as spam.
  • Blacklist Monitoring: Ensure your IP address isn't on any blacklists. Emails from blacklisted IPs are often automatically marked as spam.
  • Shared vs. Dedicated: Using a dedicated email IP address can help you better control your sender reputation.
  • Geolocation: The location of your sending IP can affect how spam filters view your emails. Some regions are considered at higher risk for spam.
  • SPF Records: Sender Policy Framework (SPF) records verify that the IP address is authorized to send emails for a particular domain.
  • Rate Limiting: Be mindful of how many emails you send in a short period, as this can trigger spam filters.
  • Warm-Up: If you're using a new IP address, gradually increase your email volume to build a positive sending reputation.
  • Monitor Feedback: Use tools to monitor how your IP address is performing in terms of deliverability and open rates.

How to Reduce Your Email Spam Score

This section will give you straightforward tips to improve your email's spam score and deliverability. Let's get to it.

  • Use an email spam checker to assess deliverability and identify issues that could send emails to the spam folder.
  • Clean up HTML code to avoid triggering spam filters. Use tools to analyze and optimize your HTML.
  • Craft subject lines carefully to avoid spam-triggering words that could increase your spam score.
  • Employ automated email spam tests for regular checks on your spam score. Real-time checkers offer immediate insights.
  • Schedule emails for optimal times and track open rates to improve deliverability.
  • Be aware of factors like sending reputation and DNS records that affect how quickly emails land in the inbox. Ensure you have correct SPF, DMARC, and DKIM records and check them reguarly.
  • Monitor the time recipients spend reading your emails; quick deletions can harm your sender reputation.
  • Keep your emailing list clean

By taking these steps, you're not just reducing your email's spam score; you're elevating its chances of being read and acted upon.

Technical Aspects Impacting Email Deliverability

Understanding the technical aspects like SPF, DKIM, and DMARC can significantly influence your email's spam score and overall deliverability.

Here's a quick rundown:

  • What is SPF: Sender Policy Framework (SPF) is a security measure that helps verify the sender's identity, reducing the chance of email spoofing.
  • What is DKIM: DomainKeys Identified Mail (DKIM) adds a digital signature to your emails, further authenticating them and boosting deliverability.
  • What is DMARC: Domain-based Message Authentication, Reporting, and Conformance (DMARC) combines SPF and DKIM, adding an extra layer of security and reporting features.
  • What is Reverse DNS: This is a DNS lookup that converts an IP address back to a domain name, helping to verify the sender.
  • Impact on Spam Score and Deliverability:
  • SPF, DKIM, and DMARC work in tandem to authenticate your emails, lowering your spam score.
  • These protocols improve your sending reputation, increasing the likelihood of your emails landing in the inbox.
  • Reverse DNS can further validate your sending IP, adding another layer of trust and improving deliverability.

By implementing these measures, you're reducing your spam score and taking significant steps to ensure your emails reach their intended destination.

What are the best practices for HTML code in emails?

When crafting your emails, the HTML code should be clean and free of red flags that might trigger spam filters. This will also help in reducing email bounces.

Here's how to optimize your HTML code for emails:

  • Clean Code: Use clean, error-free HTML to avoid triggering spam filters.
  • Inline CSS: Use inline styles instead of external or embedded CSS to ensure your email looks consistent across all email clients.
  • Avoid JavaScript: Most email clients don't support JavaScript, and it can flag your email as spam.
  • Image-to-Text Ratio: Maintain a balanced ratio to ensure your email isn't marked as spam. Too many images can be a red flag.
  • Alt Text: Always include alt text for images so recipients can understand the content even if images don't load.
  • Responsive Design: Make sure your email is mobile-friendly. Use media queries to adapt the layout for different screen sizes.
  • Validate: Run your HTML through a validator to catch any errors or issues that could affect deliverability.


How do I choose between Gmail, Yahoo, and Hotmail for business emails?

Each email provider has its pros and cons. For instance, Gmail is often praised for its robust spam filters, while Yahoo and Hotmail offer different features. Your choice of email providers will depend on your specific needs.

Here's what to consider:

  • Reliability: Look for uptime guarantees and robust infrastructure.
  • Security: Features like two-factor authentication and secure data centers are crucial.
  • Storage: Ensure adequate storage space for your business needs.
  • Integration: Check compatibility with other tools you use, like CRM software or other office applications.
  • Cost: Free isn't always better; consider the value of premium features.
  • User Experience: A clean, easy-to-navigate interface can improve efficiency.
  • Customer Support: Prompt and effective support can be a lifesaver in a crisis.
  • Compliance: Make sure the provider complies with regulations relevant to your industry.

What's the impact of invalid email addresses on my campaigns?

Invalid email addresses can be a silent drain on your email marketing efforts. Here's why they matter:

  • Bounce Rate: Invalid addresses increase your email bounce rate, which can harm your sender reputation.
  • Wasted Resources: Sending to invalid addresses consumes bandwidth and can incur costs without any return on investment.
  • Lower Engagement: High bounce rates can skew metrics and give you an inaccurate picture of engagement and deliverability.
  • Sender Reputation: ISPs monitor bounce rates. A high rate of invalid addresses can lead to your emails being marked as spam.
  • List Quality: Keeping invalid addresses in your list can degrade its overall quality and effectiveness for future campaigns.
  • Compliance Risks: Continually sending to invalid addresses can put you at risk of violating CAN-SPAM or GDPR regulations.

What Are Inboxing Issues, and How Can I Prevent Them?

Inboxing issues occur when your emails don't land in the recipient's inbox and are instead filtered into spam or other folders. Regularly testing your emails and monitoring metrics can help you identify and fix these issues.

How Do I Test the Effectiveness of My Email Campaign?

You can test your email campaign's effectiveness by tracking metrics like open rates, click-through rates, and conversion rates. A/B testing can also provide insights into what resonates with your audience.

What Role Do Images Play in Email Deliverability?

Images can make or break your email deliverability. Here's how:

  • File Size: Large images can slow loading times, affecting user experience.
  • Spam Filters: Overuse of images can trigger spam filters, sending your email to the spam folder.
  • Alt Text: Always include alt text for images to improve accessibility and provide context.
  • Relevance: Use images that are relevant to your content and message.
  • Format: Stick to commonly used formats like JPG or PNG for better compatibility.
  • Inlining: Consider inlining smaller images to reduce the number of HTTP requests.
  • Balance: Maintain a good text-to-image ratio to avoid being flagged as spam.

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