Avoid Homoglyphs in HTML to Prevent Email Spam Issues

March 13, 2025

Google’s updated spam filters now detect homoglyphs in HTML templates, making emails vulnerable to spam classification.

Email Deliverability
Email Deliverability
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Avoid Homoglyphs in HTML to Prevent Email Spam Issues

Reminder for everyone who sends marketing emails & design templates with HTML:

When you or a 3rd party is building the HTML code for your email template, ensure it doesn't contain homoglyphs to avoid triggering spam filters.With the recent update to Google's spam filtering system in November, RETVec, this has become a significant issue. Now, they can identify homoglyphs in HTML code.

This change is due to scammers previously using Unicode glyphs to bypass Google's spam filters, leading many of us to receive phished "Congratulations" emails in our inboxes. This loophole has now been closed.

Google
Gmail
Cyber Security
Spam
Spam Filters
Email Deliverability
DMARC
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