PowerCheck

PowerCheck is a web app (with a lightweight CLI) that audits your planned and running A/B tests for statistical power, duration realism, and business impact. Most teams ship tests that are doomed: too little traffic, too small an effect size, too many variants, or noisy metrics. PowerCheck connects to your analytics/experimentation stack (GA4, Amplitude, Mixpanel, Optimizely, LaunchDarkly) and pulls baseline conversion rates and traffic to generate a blunt “will this detect anything?” verdict. It recommends minimum sample size, expected runtime, and whether you should switch to sequential testing or a holdback. It also flags common failure modes like peeking, multiple comparisons, and metric dilution, and produces a one-page pre-registration plan you can paste into Jira/Notion. This isn’t a full experimentation platform; it’s a focused guardrail that prevents wasted cycles and false wins.