Does Postmark support UTF-8 characters in the “From” name?

Currently, Postmark does not support UTF-8 characters (such as accented letters or non-Latin characters) in email addresses or headers when sending via SMTP.

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Why UTF-8 isn’t supported

Postmark’s SMTP servers, which are built on Postfix, don’t have the SMTPUTF8 extension enabled. This extension is required to properly handle non-ASCII characters in email addresses and headers like the “From” name.

While SMTPUTF8 is part of the modern email standard, enabling it would require broader changes across Postmark’s sending infrastructure. For now, SMTP sending is limited to ASCII-only characters.

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Recommended workaround

If you’re sending via SMTP, use standard English (ASCII) characters in your “From” name and email address to ensure your messages send successfully.

If you need to include accented or non-Latin characters in sender details, consider using Postmark’s Email API, which provides more flexibility in message encoding.

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Learn more:

• Sending email with SMTP

• Sending email with the API