€2.99 or €3.49? Proton VPN's Pricing Test Exposed

cross-posted from: lemmy.world/post/50434194

Proton VPN’s pricing page exposed an ab-test identifier linked to two VPN Plus prices: €2.99/month (70% off) and €3.49/month (65% off). Repeated testing produced B → A → B → A → B, with the variant matching the rendered price each time. €12 difference over 24 months.

thecybersecguru.com/news/proton-vpn-ab-testing-price-difference/

Way back when, the observed ABAB sequence could be explained by one server using outdated data and another having the new data and visitors being round-robined to each in turn. I have investigated issues like this and this has happened. Not sure how many companies still use a setup like this, though. It’s been K8s clusters everywhere I’ve worked for many years now. This does indeed look like a proper AB test, the HTML already looks pretty clear.

Yeah and what’s worse is Proton denying AB testing and instead claiming that it was a promo pricing