Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
Loader.io - Loader.io is a simple cloud-based load testing service
Cherokee - High-performance web server
WebLOAD - WebLOAD - The most flexible and cost effective software for enterprise load, stress and performance testing, integrated with DevOps processes. Click for details
Caddy - The HTTP/2 Web Server with Automatic HTTPS
StresStimulus - Load testing tool for websites and mobile that works with hard-to-test applications.