Throttling

What is it?

What is it?

"Throttling" in email marketing refers to the deliberate restriction or limitation of email sending volume or frequency by email senders or service providers to manage email deliverability, prevent server overload, and maintain sender reputation. Throttling mechanisms regulate the rate at which emails are sent to recipients' mail servers, ensuring that sending practices align with industry best practices, anti-spam regulations, and recipient preferences.

Key points to remember

Key points to remember

  • Purpose: Throttling is implemented to prevent email campaigns from overwhelming recipients' mail servers or inboxes, reducing the risk of messages being flagged as spam, bounced, or blocked due to excessive sending volumes or suspicious behavior.

  • Volume Control: Throttling controls the number of emails sent per unit of time, such as per hour, per day, or per minute, to distribute sending activity evenly and prevent spikes in traffic that may trigger spam filters or congestion issues.


  • Gradual Ramp-up: When warming up a new IP address or domain for email sending, senders may gradually increase sending volumes through throttling to establish a positive sending reputation and minimize deliverability risks.


  • Compliance Considerations: Throttling practices should comply with anti-spam laws and regulations, such as the CAN-SPAM Act and the General Data Protection Regulation (GDPR), which mandate permission-based marketing, transparent opt-in processes, and adherence to recipient preferences regarding email frequency and content.


  • Impact on Engagement: While throttling helps maintain deliverability and sender reputation, excessively conservative practices may delay email delivery and reduce timeliness, potentially impacting recipient engagement and response rates.

Example of Use

Example of Use

  1. Campaign Scheduling: An email marketer schedules an extensive email campaign to subscribers but configures the email platform to throttle sending rates to a manageable level, ensuring gradual delivery over several hours or days to avoid overwhelming recipients' inboxes.


  2. Warm-up Period: A company acquires a new IP address for email sending and implements a throttling strategy to gradually increase sending volumes over several weeks, allowing mailbox providers to observe sending patterns and establish a positive reputation for the new IP.

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