What is Email Throttling?

What is Email Throttling?

Email throttling is a practice used by Email service providers (such as Gmail, Yahoo, Outlook, among others) to limit the number of Emails received from a single sender within a specific time frame. The main purpose is to prevent inbox congestion and reduce the risk of spam.

Email providers use algorithms and automated systems to monitor Email traffic. When they detect a high volume of Emails coming from a single sender in a short period of time, they may apply Email throttling. This means that the Emails from that sender are delivered more slowly, spread over a longer period, instead of being sent all at once.

How Does Email Throttling Affect Email Marketing Campaigns?

Email throttling can negatively impact your Email marketing campaigns in several ways:

• Delivery delays: Throttling causes delays in message delivery, which can be problematic—especially for time-sensitive campaigns such as flash promotions or event announcements.
• Skewed metrics: Slower delivery may result in lower open and click-through rates. Recipients might take the intended action before even receiving your Email, leading to inaccurate performance data.
• Increased risk of being marked as spam: If recipients are expecting your Email and it arrives too late, they might mistake it for unsolicited content and mark it as spam.

How to Avoid Email Throttling

To minimize the risk of Email throttling and ensure the success of your campaigns, consider the following best practices:

• List segmentation: Divide your Email list into smaller segments and send messages gradually. This reduces the chance of triggering throttling limits.
• Smart scheduling: Send Emails at strategic times when your audience is more likely to engage with them.
• Monitor IP reputation: Make sure your sending IP has a strong reputation. Poor IP reputation can increase the likelihood of throttling.
• Send relevant content: Deliver valuable and relevant content to your audience to increase engagement and reduce the risk of being flagged as spam.

In Summary

Email throttling is designed to protect users’ inboxes and prevent overload, but it can pose challenges for Email marketers. By understanding how throttling works and applying best practices, you can improve deliverability and ensure your messages reach the right audience efficiently and on time.

Updated on: 08/07/2025