Glossary Term
Email Throttling
Intentionally slowing down email sending to stay within safe limits and avoid triggering spam filters.
What is Email Throttling?
Email throttling is the practice of intentionally limiting your email sending rate to avoid triggering spam filters or exceeding provider limits. There are two types:
Provider-enforced throttling:
- Microsoft 365 may delay emails when rate limited
- Receiving servers may defer emails from fast senders
- Error codes (452, 421) indicate throttling
Intentional throttling (best practice):
- Spread emails throughout the day
- Random delays between emails
- Gradual volume increases
- Multiple domains to distribute load
Why throttling matters: Burst sending (100 emails in 1 minute) looks automated. Spread sending (100 emails over 8 hours) looks human. Even if you stay under limits, burst patterns trigger spam filters.
Our system automatically throttles sending to mimic human patterns.
Why It Matters
- 1Prevents provider rate limiting
- 2Mimics human sending patterns
- 3Protects sender reputation
- 4Required for sustainable cold email
Related Guides
Related Terms
Sending Limits
Maximum number of emails you can send per time period, set by your email provider and best practices.
Rate Limiting
Restrictions imposed by email providers on how fast you can send emails, preventing abuse and maintaining system stability.
Email Deliverability
The ability of your emails to successfully reach recipients' inboxes rather than being blocked or sent to spam.
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