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Experiment · exp-002 · Feature flag · server-side · VIP
VIP gallery lazy loading
~Inconclusive
Listings · QCT · 2025-10-01 – 2025-10-22 · 21 days · max.mueller@mobile.de
What it was
VIP pages load all listing images eagerly, including those below the fold. On mobile connections this caused LCP scores above 4s for listings with 12+ photos. The hypothesis was that lazy-loading images below the first two would reduce LCP and increase scroll depth, with no penalty to contact rate — buyers who scroll further into a gallery have demonstrated higher intent. Tested via a server-side feature flag on 50% of mobile VIP traffic.
What we learned
Learning
Lazy loading reduced mobile LCP p75 from 4.1s to 2.6s — a meaningful Core Web Vitals improvement. Gallery scroll depth increased by 11%. However, dealer contact rate showed no improvement (+0.3%, CI: -1.4% to +2.0%, reliability 0.31). Inconclusive on the primary business metric. Performance win is real but insufficient alone to justify the product change. Scheduled follow-up: test whether a "View all photos" CTA above the fold drives the contact lift we expected from scroll depth.
max.mueller@mobile.de · 2025-10-28 · current
TouchpointVIP