What are the best free and paid spam checker tools for email marketers?

Summary

Email marketers have access to a wide array of tools to combat spam and enhance deliverability, encompassing both free and paid options. Free tools like Mail-tester, Inboxbooster.com, Warmy, Senderok, and Mailjet's free plan provide content analysis, spam score assessment, and basic deliverability testing. Setting up seed accounts with various providers (Gmail, Yahoo, Hotmail) is another common free method for monitoring inbox placement. For more comprehensive solutions, paid services such as Litmus, GlockApps, Everest Validity, Zerobounce, and Email Hippo offer features like inbox placement testing, reputation monitoring, DMARC analysis, email validation, and detailed analytics. Documentation from Spamhaus, DKIM Validator, MXToolbox, and Google Postmaster Tools provide insights into IP blacklisting, DKIM validation, DNS record checks, and sender reputation management, all vital for understanding and mitigating deliverability issues. Experts caution that the effectiveness of AI-driven tools can diminish over time due to adaptive learning and that there is no perfect way to check inbox placement. A holistic approach including authentication checks, list hygiene, feedback loops, and careful selection of independent third-party authentication services is recommended.

Key findings

  • Free Tools Abundance: Numerous free tools are available for basic spam checking and deliverability testing (Mail-tester, Inboxbooster, Warmy, Senderok, Mailjet's free plan).
  • Seed Account Strategy: Utilizing seed accounts with different providers (Gmail, Yahoo, Hotmail) aids in monitoring inbox placement.
  • Premium Tools' Comprehensive Features: Paid services offer advanced features like inbox placement testing, reputation monitoring, and detailed analytics (Litmus, GlockApps, Everest Validity).
  • Importance of Email Validation: Email validation services (Zerobounce, Email Hippo) are crucial for maintaining clean lists and improving sender reputation.
  • DNS and Authentication Checks: Tools like Spamhaus, DKIM Validator, and MXToolbox help identify blacklisting and ensure proper email authentication.
  • AI Limitations in Long Term: AI-driven spam checkers effectiveness diminishes as they adapt to user behavior.
  • No single method for inbox placement: There is no reliable method to check inbox placement

Key considerations

  • Accuracy vs. Cost: Weigh the accuracy and comprehensiveness of paid tools against the cost and potential limitations of free options.
  • Proactive Monitoring Is Key: Regularly check for IP blacklisting, validate DKIM signatures, and monitor DNS records.
  • Reputation Matters: Maintain a positive sender reputation by cleaning email lists, authenticating emails, and monitoring feedback loops (Google Postmaster Tools).
  • Authentication Choices: Ensure third-party authentication services are independent from email service providers (ESPs).
  • Holistic Approach Necessary: Implement a range of tools to understand deliverability

What email marketers say
14Marketer opinions

Email marketers have a range of free and paid tools available to check and improve email deliverability and avoid spam filters. Free options include Mail-tester, Inboxbooster.com, Warmy, Senderok, and Mailjet's free plan, offering features such as content analysis, spam score assessment, and basic deliverability testing. Using seed accounts from various providers is also a common free method. Paid services like Litmus, GlockApps, Everest Validity, Zerobounce, and Email Hippo offer more comprehensive features such as inbox placement testing, reputation monitoring, DMARC analysis, email validation, and detailed analytics. It's important to note that some free tools may have limitations, such as providing a false sense of security by only checking for the presence of certain records without validating their configuration.

Key opinions

  • Free Tools: Free tools like Mail-tester, Inboxbooster.com, Warmy, and Senderok provide basic spam checking and deliverability testing.
  • Seed Accounts: Setting up seed accounts with different providers (Gmail, Yahoo, Hotmail) can help monitor inbox placement.
  • Paid Tools: Paid services like Litmus, GlockApps, and Everest Validity offer comprehensive deliverability solutions with advanced features.
  • Email Validation: Services like Zerobounce and Email Hippo focus on email list cleaning and validation to improve sender reputation.
  • Mailjet: Mailjet's free plan includes spam checker to analyze email content

Key considerations

  • Accuracy of Free Tools: Some free tools may provide limited or potentially misleading information, such as only checking for the presence of SPF records without proper validation.
  • Comprehensive Analysis: Paid tools offer more in-depth analysis, reporting, and features compared to free options.
  • Email List Hygiene: Maintaining a clean and validated email list is crucial for avoiding spam traps and improving sender reputation.
  • Custom Test Accounts: Using your own test accounts can give more accurate monitoring as you will get spam folder info and be able to analyze inbound headers.
Marketer view

Email marketer from Email Geeks mentions that Mail-tester only checks for the presence of records like SPF, even if they are misconfigured, giving a false sense of security. She recommends human eyes or <@UDEFP1J3B> tool.

May 2022 - Email Geeks
Marketer view

Email marketer from GlockApps recommends using their paid tool, which offers inbox placement testing, reputation monitoring, and DMARC analysis to identify and resolve deliverability issues.

June 2023 - GlockApps
Marketer view

Email marketer from Email Geeks suggests using multiple free accounts from different providers (Hotmail, Yahoo, Gmail, etc.) as seed accounts to check inbox placement.

February 2022 - Email Geeks
Marketer view

Email marketer from Email Hippo offers email verification services. Clean email lists avoid the spam trap and honeypot and reduces the risk of being marked as spam.

December 2024 - Emailhippo.com
Marketer view

Email marketer from Everest Validity highlights how their Everest platform provides data-driven insights into email deliverability, helping marketers monitor inbox placement, improve sender reputation, and avoid spam filters through detailed analytics and reporting.

October 2021 - Validity.com
Marketer view

Email marketer from Mailjet suggests using their free plan, which includes a spam checker to analyze email content and identify potential spam triggers before sending campaigns.

July 2024 - Mailjet
Marketer view

Email marketer from Email Geeks created Inboxbooster.com offering free inbox placement tests to identify if the email goes to spam or promo, identifying the cause (reputation, DNS, content).

December 2024 - Email Geeks
Marketer view

Email marketer from Litmus recommends their own paid service for comprehensive email testing, including spam filter analysis, pre-send checks, and rendering previews across various email clients.

March 2025 - Litmus
Marketer view

Email marketer from Mail-tester explains that their tool provides a free service where you send an email to a provided address, and they analyze its content, authentication, and server configuration to assess spam score.

July 2023 - Mail-tester.com
Marketer view

Email marketer from Email Geeks suggests that 10 test accounts will be more accurate to monitor inbox placement as you will get spam folder info and be able to analyze inbound headers.

January 2024 - Email Geeks
Marketer view

Email marketer from Senderok advises utilizing their free email spam checker to perform a detailed email analysis, check for blacklists, and enhance deliverability, especially for bulk emails.

December 2022 - Senderok.io
Marketer view

Email marketer from Warmy suggests using their free email deliverability test to quickly assess your email's spam score and identify potential deliverability issues.

October 2024 - Warmy.io
Marketer view

Email marketer from Zerobounce explains that email validation is crucial as it removes invalid or risky email addresses, thus improving sender reputation and preventing emails from being marked as spam, offering a tool for email list cleaning and verification.

December 2023 - ZeroBounce.net
Marketer view

Email marketer from Email Geeks shares that Mail-tester checks the email content and provides a score, requiring you to send an email to their provided address.

August 2021 - Email Geeks

What the experts say
5Expert opinions

Experts in email deliverability highlight the complexities and nuances of spam checking tools. Some express skepticism about the long-term reliability of AI-driven tools due to their adaptive learning capabilities. A consensus suggests that there is no perfectly reliable method to check inbox placement and data from probe accounts will differ from real user experience. Seed list testing is recommended for monitoring inbox placement; considerations when choosing tools should include features like global coverage and integration capabilities. Experts also advocate for a multi-faceted approach, including authentication checks, list hygiene, feedback loops, and reputation monitoring. Caution is advised when using third-party authentication services, ensuring they have no business ties to ESPs.

Key opinions

  • AI Limitations: AI-driven spam checkers' effectiveness diminishes over time due to learning user behaviors.
  • Inbox Placement Challenges: Reliable inbox placement checking is difficult, probe accounts don't accurately reflect real user experience.
  • Seed List Testing: Seed list (probe) testing is a valuable tool for inbox placement monitoring.
  • Holistic Approach: A range of tools including authentication, hygiene, feedback loops and reputation monitoring is beneficial for understanding deliverability.
  • Image Load Data: Analyzing image load data can also provide useful information about inbox rates.

Key considerations

  • Tool Selection: When choosing tools, consider factors such as global coverage, frequency of testing, and integration capabilities.
  • Third-Party Independence: Ensure that third-party authentication services are independent of email service providers (ESPs).
  • Data Interpretation: Be mindful of the limitations of probe account data when assessing inbox placement.
  • Multiple tools: A range of tools will be more effective in achieving inbox placement.
Expert view

Expert from Spam Resource suggests that a range of tools and services are important for understanding deliverability and inbox placement. This includes authentication checks, list hygiene services, feedback loops, reputation monitoring and seed list testing. Using these tools correctly can help reduce issues that lead to emails landing in the spam folder.

July 2023 - Spam Resource
Expert view

Expert from Email Geeks expresses doubts about the reliability of spam checker tools, as their effectiveness diminishes over time due to AI learning user-specific behaviors.

October 2024 - Email Geeks
Expert view

Expert from Word to the Wise warns to use 3rd party authentication services, especially with BIMI. These third parties should not have any business relationships with ESPs.

June 2022 - Word to the Wise
Expert view

Expert from Email Geeks explains that there's no reliable way to check inbox placement, as probe account data differs from real user experiences. Suggests analysing image load data.

April 2023 - Email Geeks
Expert view

Expert from Word to the Wise suggests using seed list testing (also known as probe testing) for inbox placement monitoring as the data collected from these tests directly affects your decisions, choose the tool based on features like global coverage, frequency of testing, and integration with other platforms.

April 2022 - Word to the Wise

What the documentation says
4Technical articles

Documentation emphasizes the importance of utilizing free tools to monitor and maintain email deliverability. Spamhaus offers an IP address lookup to check for blacklisting, while DKIM Validator verifies the validity of DKIM signatures for authentication. MXToolbox provides comprehensive DNS record checks (SPF, DKIM, DMARC) and server diagnostics. Google Postmaster Tools allows monitoring of sender reputation, spam rates, and feedback loops specific to Gmail users. Using these tools helps email marketers identify and address issues that could lead to emails being marked as spam.

Key findings

  • IP Blacklist Check: Spamhaus's IP lookup tool identifies if your sending IP is blacklisted.
  • DKIM Validation: DKIM Validator verifies the proper configuration of DKIM signatures.
  • DNS Record Checks: MXToolbox offers tools for comprehensive DNS record (SPF, DKIM, DMARC) verification.
  • Gmail Monitoring: Google Postmaster Tools provides sender reputation and spam rate data for Gmail users.

Key considerations

  • Proactive Monitoring: Regularly check for IP blacklisting and validate DKIM signatures.
  • Proper Authentication: Ensure DNS records (SPF, DKIM, DMARC) are correctly configured for proper email authentication.
  • Reputation Management: Utilize Google Postmaster Tools to monitor and maintain a positive sender reputation with Gmail users.
Technical article

Documentation from Google explains how to use Google Postmaster Tools to monitor sender reputation, spam rate, and feedback loop data, helping email marketers identify and address deliverability issues specific to Gmail users.

November 2024 - Google
Technical article

Documentation from MXToolbox explains how their free tools can be used to check DNS records (SPF, DKIM, DMARC), diagnose email server issues, and ensure proper email authentication, reducing the likelihood of spam filtering.

September 2024 - MXToolbox
Technical article

Documentation from DKIM Validator explains how to use their tool to check if your DKIM signature is valid, ensuring that your emails are properly authenticated and less likely to be marked as spam.

October 2023 - DKIM Validator
Technical article

Documentation from Spamhaus explains how to use their free IP address lookup tool to check if your sending IP is blacklisted, impacting deliverability and potentially causing emails to be marked as spam.

September 2023 - Spamhaus