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Can I use a shorter API token or password with Postmark? | Postmark Support Center

Can I use a shorter API token or password with Postmark?

For security reasons, Postmark’s API tokens are a fixed length of 36 characters. These tokens are used for both API and SMTP authentication and can’t be shortened or customized.


Why tokens can’t be shortened

Shorter credentials make your account more vulnerable to unauthorized access. To protect your messages and data, Postmark requires all tokens to remain at the full 36-character length.

While we previously supported shorter tokens in rare cases, this is no longer available due to the increased security risk.


What to do if your device doesn’t support long credentials

Some older applications or devices (like printers or scanners) may limit the length of usernames or passwords.
If you’re running into this issue:

  1. Check your device or software settings to see if there’s a way to support 36-character credentials.

  2. If not, you’ll need to use a different service for sending emails that meets your device’s compatibility requirements.

Unfortunately, Postmark’s security standards don’t allow for exceptions or custom credentials.


Learn more

Last updated October 7th, 2025

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