---
url: /relyai-acellemail/features/subject-ab.md
description: >-
  Generate four distinct, angle-tagged subject-line variants for a campaign with
  one click, then drop your favourite into the subject field — nothing changes
  until you save.
---

# Subject A/B generator

Writing the subject line is often the hardest part of a campaign, so RelyAI gives you a head start
right where you need it. In the campaign editor, a **Suggest** button sits next to the subject
field. Click it and RelyAI generates **four distinct subject-line variants** for your campaign,
each tagged by the angle it takes.

![The Suggest button beside the campaign subject field](/relyai-acellemail/img/relyai-subject-ab-suggest.png)
*RelyAI → Campaign editor → subject field*

## The four angles

The variants aren't four rewordings of the same idea — each one leans on a different psychological
angle so you can compare genuinely different approaches:

| Angle | What it plays on |
| --- | --- |
| **Curiosity** | An open loop that makes readers want to know more |
| **Benefit** | The concrete payoff for opening |
| **Urgency** | A reason to act now |
| **Question** | A direct question that invites a click |
| **Number** | A specific figure or list to anchor attention |
| **Personalization** | A line that speaks to the recipient directly |

Each suggestion is labelled with its angle, so you can pick the one that fits this send — or run a
proper A/B test with two contrasting angles.

## How to use it

1. Open the campaign editor and click **Suggest** beside the subject field.
2. Read the four angle-tagged variants.
3. Click a variant to drop it straight into the subject field.
4. Edit it further if you like.

Nothing about the campaign changes until **you save** it. Generating and even clicking a variant
only fills the field in the editor — the suggestion is a starting point, not a commitment, so you're
always in control of what actually goes out.

::: tip Pair it with rewrite
Chosen a variant but want to nudge the tone? Select it and use the sparkle (✦) popover to make it
[shorter, friendlier or more formal](/relyai-acellemail/features/rewrite).
:::

## Related pages

* [Universal rewrite](/relyai-acellemail/features/rewrite) — refine a chosen subject line in place
* [Coaches](/relyai-acellemail/features/coaches) — the campaign coach for preheaders, send times and A/B-split math