GTmetrix
GTmetrix is a web-based tool for analyzing the performance of websites and web pages. It provides insights into load times, resource usage, and opportunities for improvement, helping developers optimize site speed and user experience. The service uses automated testing engines and combines data from established performance tools to generate its analysis. Historically it drew on Google PageSpeed Insights and YSlow, and in its current iterations incorporates elements from Lighthouse-based assessments as well.
Key outputs include page load time, total page size, and the number of requests, along with one
Features and accessibility vary by plan. The free tier provides basic testing and limited history, while paid
Typical use cases include benchmarking page performance, monitoring performance over time, and validating optimization efforts. GTmetrix