Can an email signature trigger spam filters?
Yes, poorly constructed or overloaded email signatures can contribute to spam detection, while properly coded email signatures created with MySignature are safe for email deliverability. Email providers evaluate dozens of factors when filtering messages, and an email signature is only one part of the overall message content.
An email signature is more likely to trigger spam filters if it includes any of the following issues:
Too much information: Including excessive details - such as multiple phone numbers, numerous social media links, or lengthy legal disclaimers - can flag your message as suspicious.
Image-heavy layouts: Relying heavily on images rather than text in your signature can trigger spam filters that automatically flag image-dense emails.
Non-compliant HTML or CSS code: Using broken or non-standard HTML or CSS code in a signature can cause spam filters to treat the code as an attempt to hide malicious content.
To prevent your email signature from negatively affecting deliverability, keep your signature design simple, include only essential contact details, and use compliant HTML and CSS code.
What else causes emails to land in the spam folder?
Even if your email signature follows best practices, emails can still end up in the spam folder due to other deliverability factors:
Email body content: Using words or phrases commonly associated with spam, or adding excessive links and images in the main body of the email, can trigger spam filters.
Sender reputation: Sending messages from an email address or domain with a poor sending history increases the likelihood of spam filtering.
Email authentication: Failing email authentication checks - which verify your sender identity and confirm the message was not altered - can cause receiving servers to route your email to spam.
Recipient behavior: When recipients mark your messages as spam, email providers learn from that feedback and filter similar future emails into the spam folder.
How do MySignature email signatures perform in spam tests?
Emails sent with HTML signatures created by MySignature pass spam filter checks with minimal impact on spam scores. To verify deliverability, MySignature tested HTML signatures containing links and images using Mail-tester across two common sending setups.
Standard email clients (Gmail, Yahoo, Outlook)
In a test simulating a standard outreach or marketing email sent through a regular email client (such as Gmail, Yahoo, or Outlook), the test email included:
2 links in the email body
Bold text formatting
An emoji
A MySignature HTML email signature containing links and images
Test result: When analyzed in Mail-tester, adding the MySignature HTML email signature and image had only a small impact on the overall spam score, confirming that the email safely passes spam detection.
As you can see, using an HTML email signature and image in your email has a small impact on getting into Spam.
Email marketing platforms (Mailchimp, SendGrid)
In a second test simulating email campaigns sent through bulk email platforms (such as Mailchimp and SendGrid) with a MySignature HTML email signature attached:
Test result: When analyzed in Mail-tester, the campaign email with the MySignature HTML signature passed spam filter checks without hurting email deliverability.
How can I keep my MySignature email signature from triggering spam filters?
To maintain strong inbox placement when using a MySignature email signature:
Keep your MySignature layout clean and include only essential contact information rather than excessive links, phone numbers, or long disclaimers.
Balance text and images in your signature instead of using a single large image or too many graphics.
Maintain a healthy sender reputation and ensure your email domain authentication is properly configured.