Loadimpact

Load Impact is another good tool for performance testing, allowing load tests for websites, web apps, mobile apps and APIs in seconds. From automating the testing process for continual Ôready to releaseÕ updates, through to rigorous API testing, web app testing and mobile testing under a range of different network connections and conditions (e.g. 3G, 4G, etc.), Load Impact gives you control over and insights into a broad spectrum of performance data.

http://loadimpact.com/