Verified Confidence: medium
Primary source found; it says the same thing, the scope matches, and it is reasonably current.
Safe rephrasing
Cloudflare's 2025 data show Google Optimize, discontinued in September 2023, fell from 14% to 4% of detected A/B testing tools, while VWO extended its lead over Optimizely.
What the source says
Among A/B testing tools, VWO ’s share grew by eight percentage points year-over-year, extending its lead over Optimizely , while Google Optimize , which was sunsetted in September 2023, saw its share fall from 14% to 4%.
Cloudflare Radar — Cloudflare Radar 2025 Year in Review
- Commonly cited as
- "Which A/B testing tool do sites use?"
- True origin
- Cloudflare Radar — Cloudflare Radar 2025 Year in Review
- Type
- Reference fact: A frequently needed number or rule taken directly from a primary source (e.g. Pew, Census, IAB/PwC, FTC), with its as-of date.
- Year
- 2025
- Data as of
- 2025 (year to date, through early December)
- Last checked
- Method & sample
- Cloudflare detection of third-party tools on sites it serves, 2025 vs 2024.
- Drift between quote and source
- Share of detected A/B testing tools on Cloudflare-served sites, not of all websites
- Remaining 4% is likely leftover code from a discontinued product
- Interest
- Cloudflare sells network and security services.