Summary
Various APIs and tools can assist in checking email content for spam triggers and improving deliverability. Postmark offers a Spam Check API utilizing SpamAssassin, while SendForensics provides pre-send content analysis, identifying problematic phrases and keywords. GlockApps performs comprehensive spam testing by simulating sends to multiple mailbox providers. Litmus and EmailOnAcid offer testing environments to preview emails across different clients and identify spam filter triggers. ZeroBounce provides a suite of tools including content analysis, spam trap detection, and blacklist monitoring. Mailjet suggests A/B testing email content. For specific word triggers, <http://spamtriggerwords.com> is recommended. Beyond content, experts emphasize focusing on legitimate email practices (consent, easy unsubscribe, clean lists), proper authentication (SPF, DKIM, DMARC), and maintaining a good sender reputation through engagement. Mailgun’s Email Validation API validates email addresses, and Microsoft's Exchange Online Protection provides anti-spam message headers for analysis. AWS recommends best practices for bulk email authentication. Apache SpamAssassin offers an open-source content analysis solution.
Key findings
- Postmark & SpamAssassin: Postmark's Spam Check API integrates SpamAssassin for content analysis and scoring.
- SendForensics Pre-Send: SendForensics analyzes content for problematic phrases and keywords before sending.
- GlockApps Comprehensive Testing: GlockApps simulates sends to multiple providers for comprehensive spam filter testing.
- Litmus & EmailOnAcid Testing: Litmus and EmailOnAcid provide testing environments for previewing emails and identifying spam triggers.
- ZeroBounce Suite: ZeroBounce provides a suite of tools for verification, deliverability and content analysis.
- Mailjet A/B Testing: Mailjet suggests A/B testing content to identify spam filter triggers.
- Spam Trigger Word List: Reference <http://spamtriggerwords.com> for specific word triggers.
- Legitimate Practices: Focus on consent, unsubscribe options, and clean lists.
- Authentication Importance: Proper SPF, DKIM, and DMARC authentication is crucial.
- Engagement and Reputation: High engagement and positive sender reputation improve deliverability.
- Mailgun Validation: Mailgun's API validates email addresses to prevent deliverability issues.
- Microsoft Headers: Analyze anti-spam message headers for insights into filtering.
- AWS Authentication: AWS recommends authentication best practices for bulk sending.
- Open Source SpamAssassin: Apache SpamAssassin provides an open-source solution for content analysis.
Key considerations
- Content Analysis Depth: Evaluate the depth of content analysis provided by different tools.
- Testing Environment: Consider the need for comprehensive testing across multiple mailbox providers and email clients.
- API Integration: Assess the ease of API integration with existing workflows.
- Holistic Approach: Combine content analysis with address validation, authentication, and list management for optimal deliverability.
- Ongoing Monitoring: Continuously monitor engagement, reputation, and deliverability metrics.
- Balance Tool Use: Don't rely solely on tools; combine them with best practices and expert advice.
What email marketers say
8 marketer opinions
Several APIs and tools can check email content for spam triggers before sending. Postmark offers a Spam Check API, while SendForensics provides pre-send testing highlighting problematic phrases and keywords. GlockApps offers comprehensive spam testing by sending emails to various mailbox providers and reporting on placement. Litmus and EmailOnAcid provide email testing and deliverability tools, including spam filter testing. ZeroBounce offers email verification and deliverability tools with content analysis, and Mailjet suggests A/B testing email content to identify what triggers spam filters.
Key opinions
- Postmark API: Postmark offers an API to check email content for potential spam issues.
- SendForensics Analysis: SendForensics performs pre-send testing, identifying problematic phrases and keywords.
- GlockApps Testing: GlockApps provides comprehensive spam testing by sending emails to various mailbox providers.
- Litmus/EmailOnAcid Testing: Litmus and EmailOnAcid offer testing tools to preview emails and identify spam filter triggers.
- ZeroBounce Suite: ZeroBounce provides a suite of email verification and deliverability tools, including content analysis.
- Mailjet A/B Testing: Mailjet suggests A/B testing to determine which content triggers spam filters.
Key considerations
- API vs. Testing Platform: Consider whether an API for automated checks or a testing platform for comprehensive analysis is more suitable.
- Content Analysis Focus: Evaluate which tools provide the most detailed content analysis, including identifying specific phrases and keywords.
- Integration Needs: Determine how easily the chosen tools integrate with existing email marketing workflows.
- Comprehensive Testing: Assess whether comprehensive testing across multiple mailbox providers is necessary.
- Email Verification: Email verification and deliverability tools are helpful to identify and resolve issues that could impact email deliverability.
- A/B Testing Considerations: A/B testing can show what kind of copy or content is more likely to be filtered by spam, by trialing different content to different users.
Marketer view
Email marketer from Litmus shares that their platform provides email testing and deliverability tools, allowing users to preview emails across different email clients and devices. It also includes spam filter testing to identify potential issues that could affect inbox placement.
4 Apr 2022 - Litmus
Marketer view
Marketer from Email Geeks suggests using SendForensics for pre-send testing, which provides content-specific results, including problematic phrases, keywords, and weighted words.
5 Oct 2023 - Email Geeks
What the experts say
4 expert opinions
Experts recommend several strategies to avoid email spam filters, starting with consulting <http://spamtriggerwords.com> for a list of spam trigger words. Focus on legitimate email practices such as explicit consent, easy unsubscribe options, and maintaining clean, engaged lists, rather than just avoiding specific words. Proper email authentication (SPF, DKIM, DMARC) is crucial for mailbox providers to identify legitimate senders. Sender reputation and engagement significantly impact deliverability; high engagement improves deliverability, while low engagement and spam complaints increase the risk of being filtered as spam.
Key opinions
- Spam Trigger Words List: Consult <http://spamtriggerwords.com> for a list of words to avoid.
- Legitimate Practices: Prioritize explicit consent, easy unsubscribe, and clean lists over solely avoiding specific words.
- Authentication Importance: Proper email authentication (SPF, DKIM, DMARC) helps mailbox providers identify legitimate senders.
- Engagement Impact: Sender reputation and engagement significantly impact deliverability.
Key considerations
- Holistic Approach: Focus on legitimate email practices as a foundation, not just avoiding specific words.
- Authentication Setup: Ensure proper setup of SPF, DKIM, and DMARC for authentication.
- List Hygiene: Maintain clean and engaged email lists to improve sender reputation.
- Engagement Monitoring: Monitor engagement rates and spam complaints to identify and address potential deliverability issues.
Expert view
Expert from Word to the Wise stresses the importance of sender reputation and engagement. High engagement rates signal to mailbox providers that recipients find the emails valuable, leading to improved deliverability. Conversely, low engagement or spam complaints negatively impact sender reputation and increase the risk of emails being filtered as spam.
2 Nov 2024 - Word to the Wise
Expert view
Expert from Email Geeks recommends <http://spamtriggerwords.com> as a definitive source for spam trigger words.
9 May 2023 - Email Geeks
What the documentation says
5 technical articles
Several documentation sources highlight tools and APIs for checking email content and improving deliverability. Postmark's Spam Check API analyzes content, provides a spam score, and identifies triggered rules, leveraging SpamAssassin. Mailgun's Email Validation API focuses on syntax, disposable addresses, and spam traps. Apache SpamAssassin is an open-source platform using content analysis and other techniques to detect spam characteristics. Microsoft's Exchange Online Protection (EOP) adds anti-spam message headers, providing insights into spam filtering processes. AWS recommends best practices for authentication when using their bulk email service to avoid spam filters.
Key findings
- Postmark's Spam Check API: Analyzes content, provides a spam score, and highlights triggered rules using SpamAssassin.
- Mailgun's Email Validation API: Checks for syntax errors, disposable addresses, and spam traps to improve deliverability.
- Apache SpamAssassin: Open-source platform employing content analysis and other techniques for spam detection.
- Microsoft's EOP Headers: Adds anti-spam message headers, providing details about the spam filtering process.
- AWS Authentication: AWS recommends best practices for authentication to avoid spam filters when sending bulk email.
Key considerations
- Content vs. Address Validation: Consider whether the focus is on analyzing email content for spam triggers or validating email addresses to prevent deliverability issues.
- SpamAssassin Integration: Leverage SpamAssassin, either directly or through services like Postmark, for robust content analysis.
- Header Analysis: Analyze anti-spam message headers added by services like Microsoft EOP to understand why emails are flagged as spam.
- Authentication Importance: Implement proper authentication (SPF, DKIM, DMARC), especially when sending bulk email through services like AWS, to improve deliverability.
- Holistic Deliverability Strategy: Combine content analysis with address validation and proper authentication for a comprehensive deliverability strategy.
Technical article
Documentation from Microsoft highlights the anti-spam message headers that are added to inbound emails by Exchange Online Protection (EOP). These headers provide details about the spam filtering process, including the spam confidence level (SCL) and the rules that were triggered. Analyzing these headers can help identify why an email was marked as spam.
29 Mar 2023 - Microsoft
Technical article
Documentation from Postmark explains that their Spam Check API helps identify potential spam issues in email content before sending. It analyzes HTML and plain text content, providing a spam score and highlighting specific rules that are triggered. The API uses SpamAssassin to perform these checks.
30 Oct 2021 - Postmark
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