A/B Testing Best Practices: Stop Guessing, Start Scaling

The biggest mistake in A/B testing isn't picking the wrong variant — it's testing too slowly. Parallel testing is the answer.

Run tests on creative, copy, and audience segments simultaneously. Auto-split traffic evenly and let statistical significance emerge naturally.

Set a minimum sample size before calling a winner. Postie surfaces significance alerts so you promote winners automatically — no spreadsheet required.

The goal isn't perfection on test one. It's a compounding loop: test, learn, deploy, repeat — every week.