The one-sentence version#
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 you should care#
Arriving when a person is actually checking mail lifts engagement, and engagement lifts reputation.
The mental model#
Think of email send time optimization as a contract between you and the mailbox providers receiving your mail. You publish or configure something they can check; they check it on every message; the result feeds their decision about where your message lands. Everything below is about making that check pass consistently.
Your first setup, step by step#
- 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.
Words you will see#
- Mailbox provider: Gmail, Microsoft, Yahoo, Apple, and the corporate gateways that decide where mail lands.
- Authentication: proof that a message is from who it says it is (SPF, DKIM, DMARC).
- Reputation: the provider's running score of your domain and IP.
- Placement: whether a message reaches the inbox, spam, or is rejected.
Common mistakes#
- Sending everything at 9 a.m. in your own time zone.
- Blasting the full list in one minute and tripping provider throttles.
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.