Below you can find a list of good tools for web testing. Such tools are very helpful when you want to experiment with your website.
Pingdom is a performance and website service that aims to make websites faster and more reliable. They have a wide range of online tools for any types of website, regardless of who you are or how big your website is.
Experiments is a relatively new tool in Google Analytics and allow you to do A/B tests on your website. Read more to get started.