Ideally it should be on the server side, so you're right there. Client side A/B testing isn't the best way to handle things. However, it's sometimes a necessar

Ideally it should be on the server side, so you're right there. Client side A/B testing isn't the best way to handle things. However, it's sometimes a necessary evil due to: 1. The original company not budgeting time/effort from their existing dev teams to work on A/B testing, and wanting to outsource it instead. 2. Said company and their tech department being nervous about letting outsiders actually access the source code for their site/app. 3. Or said company wanting the analytics/features that VWO/Target/Optimisely/whatever offer, and not wanting to have code up the same analytics toolbox themself.