# A/B testing & Smart Send

> Test subject lines or content, and send at each contact's best hour.

_Source: https://hexafloww.com/docs/email/ab-testing-smart-send_

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Two options in the campaign wizard help you get more opens without extra work.

## A/B testing

Turn on A/B testing in the **Content** step to compare two versions.

- **Content test** — two different subject lines for the same template.
- **Send-time test** — the same email sent at two different hours.

HexaFloww sends each version to a slice of your audience (20% by default), waits, then sends the **winning version** to everyone else automatically. The winner is judged on open rate, or click rate if you pick that.

> [!NOTE]
> A/B testing needs a reasonably large audience to be meaningful — a few hundred recipients minimum, so each variant slice is big enough to compare.

## Smart Send

Smart Send delays each contact's email to the hour they're most likely to open, based on when they've opened past campaigns.

- **Per-contact** — each person gets it at their own best hour.
- **Global** — the whole send shifts to the best overall hour.

Contacts with no open history fall back to a sensible default time.

> [!TIP]
> Use Smart Send for newsletters and non-urgent campaigns. For time-sensitive announcements, send at a fixed time instead.