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Understanding Email Bounce Backs: Hard Bounce vs Soft Bounce
Understanding Email Bounce Backs: Hard Bounce vs Soft Bounce

What is a soft/hard bounce in the world of emails?

Sean Placido-Stewart avatar
Written by Sean Placido-Stewart
Updated over a week ago

In the world of email communications, encountering bounce backs is quite common. Understanding the difference between a "hard bounce" and a "soft bounce" can help you maintain a healthy email list and improve your email delivery rates. In this article, we will explore what hard and soft bounces are, along with examples to help you easily differentiate between the two.

What is an Email Bounce Back?

An email bounce back occurs when an email fails to deliver to the intended recipient's inbox. The email server sends a message to the sender explaining why the email could not be delivered. Bounce backs can be categorised into two main types: hard bounce and soft bounce.

Hard Bounce

A hard bounce is a permanent delivery failure, indicating that the email cannot be delivered to the recipient's inbox. The primary reasons for a hard bounce include:

  • Invalid Email Address: The email address does not exist. For example, you intended to send an email to but mistakenly typed

  • Domain Issues: The domain name does not exist or is unavailable.

  • Blocked Email: The recipient's server has blocked the sender's IP or email address.

Examples of Hard Bounce

Sending an email to non-existent email address:

Typographical errors in the email address: instead of

Note: Stampede automatically removes email addresses that cause hard bounces from your list since these email addresses certainly do not exist, helping to maintain the quality of your email list.

Soft Bounce

A soft bounce is a temporary delivery failure, suggesting that while the email address is valid, the email cannot be delivered at the moment but might be deliverable later. The primary reasons for a soft bounce include:

  • Mailbox is Full: The recipient's mailbox has reached its storage limit, and cannot accept new emails until space is freed up.

  • Server Issues: The recipient's email server is temporarily down or experiencing technical issues.

  • Email Message Issues: The email message is too large, or contains attachments that are too large to be accepted by the recipient's server.

Examples of Soft Bounce

Sending an email to a full inbox: where the recipient's mailbox has exceeded its storage capacity.

Email server downtime: A temporary issue with the recipient's email server, making it unable to process incoming emails.

Note: Despite the temporary issues causing soft bounces, Stampede retains these email addresses in your list, as they may successfully receive future emails once the issues are resolved.


Understanding the differences between hard and soft bounce backs can help you manage your email communications more effectively. By paying attention to the type of bounce back and the reason provided, you can take appropriate actions to ensure successful email delivery in the future. Keep a close watch on your bounce-back rates and adjust your email strategy as needed to foster a positive sender reputation.

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