Blitz.io is a cloud-based performance testing platform that allows users to benchmark and analyze the performance of their web applications and websites. It provides a comprehensive suite of tools and services to help web developers and IT professionals to measure the speed and performance of their websites, identify and fix potential problems, and optimize their web applications for the best user experience. Using Blitz.io, users can simulate thousands of concurrent users accessing their website and determine how it responds under different traffic loads. This helps users understand the performance of their website and identify potential bottlenecks and weaknesses. It provides several features such as real-time monitoring, load testing, result analysis, and benchmarking. It also offers an API and integration with popular web development frameworks such as Ruby on Rails, Django, and Node.js.
It will continue to exist, you can configure the realistic behavior of user visits.
It has a nice (and usable) free plan, and it's simpler than Impact Charge.