How We Reduced Text Input Lag to Improve Web Performance: a Grammarly Case Study
Grammarly's team addressed performance issues in their browser extension that caused user input lag, especially for power users with large documents. They established metrics to measure input latency and performed lab-based benchmarking to identify bottlenecks. Solving these issues involved redesigning user experience (e.g., delaying checks), optimizing highlight updates, and making suggestion processing asynchronous, resulting in a 91% reduction in input lag. Additionally, user experience improved, leading to a 9% decrease in users disabling the extension. Ongoing efforts focus on further performance improvements, including memory and CPU usage management.
https://www.grammarly.com/blog/engineering/reducing-text-input-lag/