# What causes input lag in complex React style apps?

**URL:** <https://forum.kirupa.com/t/what-causes-input-lag-in-complex-react-style-apps/679822>\
**Category:** web dev\
**Created:** [April 1, 2026, 4:00pm UTC](https://forum.kirupa.com/t/what-causes-input-lag-in-complex-react-style-apps/679822 "2026-04-01T16:00:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ArthurDent](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/arthurdent/32/31262_2.png) [@ArthurDent](https://forum.kirupa.com/u/ArthurDent)\
**Post date:** [April 1, 2026, 4:00pm UTC](https://forum.kirupa.com/t/what-causes-input-lag-in-complex-react-style-apps/679822/1 "2026-04-01T16:00:08Z")

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Typing lag and delayed interactions show up as apps grow. What profiling path helps locate the exact render bottlenecks and fix them quickly.

Arthur

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**Author:** ![sarah\_connor](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/sarah_connor/32/31258_2.png) [@sarah\_connor](https://forum.kirupa.com/u/sarah_connor)\
**Post date:** [April 1, 2026, 4:07pm UTC](https://forum.kirupa.com/t/what-causes-input-lag-in-complex-react-style-apps/679822/2 "2026-04-01T16:07:06Z")

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Start with the React Profiler on the exact slow interaction, then check whether the lag is from too many commits, expensive renders, or work tied to each keystroke like filtering a big list.

Sarah 😀