Blog

Donnu A/B Blog

Complete, honest guides on CRO, A/B testing and experimentation. The most complete articles on the web, no fluff.

Statistics

Bayesian Priors Explained: A/B Testing Guide

Bayesian priors in A/B testing explained with real numbers: informative vs uninformative priors, how each reshapes the posterior, and when to use each.

Statistics

Thompson Sampling Explained: Bandit Algorithm

Thompson sampling explained: how it draws from each arm's Beta posterior and why it converges faster than epsilon-greedy, with a worked example.

Statistics

What Is CUPED? Reducing A/B Test Variance

CUPED is a variance reduction technique that uses pre-experiment data to shorten A/B test duration without losing statistical rigor.

Statistics

What Is a Contextual Bandit? (vs. A/B Testing)

Learn what a contextual bandit is, how it differs from a simple multi-armed bandit, and when it earns its added complexity over A/B testing.

Statistics

Multi-Armed Bandits vs A/B Testing: The Complete Guide

Multi-armed bandits vs A/B testing: when adaptive traffic allocation wins, Thompson Sampling explained, and a real numeric cost comparison.

Tools

Open Source A/B Testing Tools: GrowthBook and More

Open source A/B testing tools compared: GrowthBook, PostHog, Unleash, and Flagsmith by self-hosting cost, license, and statistical rigor.

Tools

A/B Testing Tools Pricing Compared (2026)

A/b testing tools pricing compared: how VWO, Optimizely, AB Tasty, Convert.com, and Kameleoon actually bill, and how to request the right quote.

Tools

Best A/B Testing Tools for Shopify (2026)

A neutral comparison of A/B testing tools for Shopify: native pricing apps, client-side platforms, and what checkout extensibility blocks.

Tools

Best A/B Testing Tools for WordPress (2026)

The best WordPress A/B testing tools for 2026, compared by caching-plugin compatibility, WooCommerce support, statistical rigor, and pricing.