Email Subject Optimizer

Generate high-converting subject line variants, score them, and select the best for your audience.

When to Use

• "Write subject lines for this email"
• "Our open rates are low — improve the subject line"
• "Generate variants for A/B testing"
• "Write cold outreach subject lines for [segment]"

Prerequisites

• ANTHROPIC_API_KEY
• Email body or core message, audience segment

Workflow

Step 1: Extract the core hook