Parallax scrolling makes background elements scroll at a different speed than foreground content, creating an illusion of depth as you move down the page. It became wildly popular around 2013 and has been polarizing ever since. Designers love the visual richness. Performance engineers hate the computational cost. Conversion specialists are somewhere in the middle.
The hard truth: parallax has never been shown to improve conversion rates. It can improve engagement metrics like scroll depth and time on page, but those aren't conversions. If your parallax effect adds 200ms to page load time and causes janky scrolling on mid-range phones, you've traded a visual flourish for real performance degradation. And performance impacts conversions directly.
If you're going to use it
Keep it to one or two subtle sections, not the entire page. Use CSS-based parallax (transform: translate3d) rather than JavaScript scroll listeners, which cause far more performance issues. Test on actual mobile devices — not just Chrome DevTools — because parallax is often disabled on iOS Safari and looks broken on many Android devices. And make sure the effect degrades gracefully when it can't run.
Better alternatives for visual interest: scroll-triggered fade-ins (lighter weight, same engagement boost), alternating section backgrounds, embedded video or animation that plays without scroll-jacking. You can make a landing page feel dynamic and modern without parallax. Most of the highest-converting pages we analyze don't use it at all.