Generate Segmented A/B Subject Lines and Preview Text for Any Email Campaign with Breeze

Subject lines determine whether your email gets opened or ignored. This Breeze prompt generates five subject lines and preview text pairs for a single email, each testing a different angle, urgency, curiosity, benefit, social proof, and personalisation, tailored to a specific audience segment in your HubSpot CRM. Use it before any campaign send to run a meaningful A/B test rather than guessing which approach will land. The output is a ready-to-use table you can copy directly into HubSpot's email editor.

Prompt of the week:

#1 Subject line text generation for A/B testing

Let's start with the one that everyone talks about but few do well, subject lines.

We start by using Breeze Assistant to generate multiple subject lines and preview text variations for the same email, tailored by audience segment, so you can run meaningful A/B tests.

HubSpot's own analysis shows that AI-optimised subject lines can increase open rates by up to 30%. Personalised subject lines are reported to be 50% more likely to be opened. The HubSpot community consistently highlights subject line optimisation and segmented testing as the highest-impact, lowest-effort win when adopting Breeze. So let us give it a go.

Prompt structure

Simply paste the following prompt to your Breeze Assistant and adjust the placeholder details in CAPITAL letters for your own.

Role: You are an email marketing specialist for [COMPANY NAME] 

in the [INDUSTRY] space.

Task: Generate 5 subject line + preview text pairs for a marketing 

email about [TOPIC/OFFER].

Audience: [SEGMENT DESCRIPTION — e.g., "marketing managers in SaaS 

companies who downloaded our whitepaper in the last 30 days"].

Goal: [PRIMARY ACTION — e.g., "get them to register for our upcoming 

webinar"].

Tone: [TONE — e.g., Professional but approachable].

Constraints:

- Subject lines must be under 50 characters

- Each variation should test a different angle:

1. Urgency/scarcity
2. Curiosity/question
3. Benefit-led/value proposition
4. Social proof/data point
5. Personalised (using a personalisation token like first name or company) 

- Preview text should complement (not repeat) the subject line

- Avoid spam-trigger words like "free," "act now," or all caps

Output format:
| # | Subject Line | Preview Text | Angle Being Tested |

Beyond the prompt:

Think of this prompt as your starter kit, not the finish line. The real power comes when you start building a library of tested prompts that your team can reach for depending on the situation: product launches, seasonal campaigns, event invitations, post-purchase nurtures, and so on.

Combine this with what we covered last week on custom Breeze Assistants and you can create a dedicated assistant with email marketing expertise baked into its personality, feed it your brand voice guide via a Knowledge Vault, and have it ready for anyone on your team to use.