What email send time optimization is#
Send time optimization chooses when to deliver each message, either by segment (time zone, historical engagement windows) or per recipient using predicted open behavior.
Why it matters#
Arriving when a person is actually checking mail lifts engagement, and engagement lifts reputation.
How mailbox providers use it#
Gmail, Microsoft, and Yahoo combine authentication results, sender reputation, and recipient engagement into a placement decision made per message. Email send time optimization feeds directly into that model, and weaknesses compound with other signals.
How to measure the impact#
- Baseline inbox placement with seed tests before any change.
- Make one change at a time and hold volume steady.
- Re-test after 48 to 72 hours; provider models need time to update.
- Track Postmaster Tools and SNDS alongside your seed results.
Improving it#
- Capture time zone at signup or infer from engagement.
- Analyze past click timestamps by segment.
- Use your platform's per-recipient optimization if available.
- Spread large sends over hours to avoid rate limiting.
Frequently asked questions#
What is the best time to send marketing emails?
There is no universal answer; mid-morning local time performs well for many B2B lists, but your own data beats benchmarks.