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Subject Line Splitter

emailespdaily cycle

A/B test email subject lines to maximize open rates. The agent generates subject line variants with labeled hypotheses, deploys them via your ESP, and iterates overnight based on real open rate data.

Primary Metric

Open Rate

↑ Higher is better

Experiment Settings

Variants per round: 4

Max rounds: 10

Min sample size: 500

Guard Rails
Experiments auto-pause if these thresholds are breached
Minimum 5% open rateFloor: 5.0%
Max 0.5% unsubscribe rateFloor: 0.5%