What is Email Throttling?
Email throttling is the deliberate limitation of email sending speed, controlling how many emails leave your inbox per hour, per day, or per sending window. Rather than blasting hundreds of emails simultaneously, throttling spaces them out to mimic natural human sending patterns and avoid triggering spam detection systems.
Why Throttling Matters
Email providers like Gmail and Outlook monitor sending patterns for suspicious behavior. Sudden bursts of high-volume email from a single address are a classic spam indicator. Throttling protects your:
- Sender reputation: Gradual, consistent sending looks natural.
- Inbox placement: Avoid spam folder triggers.
- Domain health: Prevent blacklisting from volume spikes.
- Account standing: Avoid provider-imposed sending limits.
Recommended Throttling Limits
For cold outbound email:
- Per inbox: 30-50 emails per day maximum.
- Per hour: Spread sends across the business day (5-8 per hour).
- Ramp-up period: Start at 10-15/day for new inboxes, increase by 5/day weekly.
- Weekend sends: Reduce or eliminate to match natural behavior.
Throttling Best Practices
- Add random delays: 30-90 second randomized gaps between sends feel more human.
- Respect time zones: Send during business hours in the recipient's timezone.
- Account for inbox rotation: Distribute total volume across multiple inboxes.
- Monitor in real-time: Watch for delivery errors that suggest you're hitting limits.
- Adjust seasonally: Holiday periods may require reduced volume.
How FlowStrata Manages Throttling
FlowStrata automatically manages sending speed across all client inboxes, distributing volume based on each inbox's reputation health and age. Our system uses randomized delays, timezone-aware scheduling, and real-time deliverability monitoring to ensure every email sends at a pace that maximizes inbox placement.