BlazeMeter!

The Apache JMeter desktop application is open source software, a 100% pure Java application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions.

An open source load testing tool written in Python. Locust allows you to define user behaviour with Python code, and swarm your system with millions of simultaneous users.

Load tests secure the performances of your web and mobile applications, whatever the number of visitors. They preserve your brand image and your sales revenues, all along your company's growth.

Loader.io is a simple cloud-based load testing servicethat allows you to stress test your web-apps & apis with thousands of concurrent connections. Made by the team behind SendGrid.

LOIC is an open source network stress testing application, written in C#.

Blitz makes load and performance testing of your web site, API, iPhone and Android and Facebook apps a fun sport.

SOASTA's powerful load testing and performance monitoring solutions give you a crystal-clear view of the relationship between end-to-end performance, user behavior and business goals, and provides the actionable intelligence.

Load Testing for Everyone

How many users can my web site handle? Load Impact is an online load testing service that lets you stress test your web site with just a few mouse clicks.

Performance and Load Testing with Enterprise-Level Features using a familiar jMeter interface.

Cavisson NetStorm is a cost-effective, performance enhancing and easy-to-use appliance for enterprise applications. It is an extremely powerful load generator that provides an accurate estimation of Client Perceived Response Time (CPRT) enabling IT companies to guarantee the Service Level Agreements (SLA). Its advanced technology efficiently handles load variables, user realism, application realism and network realism. NetStorm is a proven solution providing root cause of the issues where legacy solutions failed, prompting Several Fortune 100 companies switching over to using NetStorm. »

Free Cloud Load Testing Service, Speed Testing for Websites, Applications and APIs. Helps you run load and performance tests from within browsers in minutes.

PurpleStrike Real Time (RT) load tester is a turnkey performance testing services on the cloud with intuitive user interface. You can automate real applications and run web applications from real browsers to generate real time load scenarios.

Apica ProxySniffer ™ is a professional and high-duty Web Load and Stress Testing Tool that runs on Java.