Smart Subjects AI-Powered Subject Lines & Preview Texts

Use AI to craft compelling email subject lines and preview texts that boost open rates and save time.

Smart Subjects is a tool that helps newsletter publishers quickly generate effective, on-brand email subject lines and preview text using AI.

Writing compelling subject lines and preview texts can take time and effort. Smart Subjects reduces that workload by suggesting optimized options based on your newsletter content and past performance.

How It Works

When scheduling a newsletter, you’ll see a Generate with AI icon '✨' in the Subject line and Preview text fields.
The AI uses your newsletter’s themes, headlines, and top-performing past subject lines to suggest options.
You can refine or regenerate these suggestions before sending.

How to Use Smart Subjects

Smart subjects | HubSpot Video

Compose your newsletter as usual.
Click Preview and Schedule.
On the right-hand side, locate the Inbox Preview section.
In the Email Subject or Preview Text field, click the AI icon.
The field will display “Generating…” and then populate with the AI suggestion.

Review the result: you can edit, refine, or regenerate until you’re satisfied.

ℹ️ Note

If you’re not scheduling immediately, be sure to Save as Draft so your AI-generated subject line and preview text are not lost.

Best Practices Built In

Our generator is designed to:

Avoid spam trigger words and phrases.
Keep subject lines concise, simple, and attention-grabbing.
Learn from your top 5 performing subject lines to optimize for higher open rates over time.