Tools

BrowserStack

BrowserStack is a great tool to test website design on multiple platforms and in multiple browsers. Free plan includes 30 minutes of time.

Clickdensity

Clickdensity is a very useful heat map/usability tool. Free to use for 1 site and 1 page with 5,000 click max.

Pingdom

Pingdom is an excellent service to monitor server uptime and performance. Be the first to know when your site is down. Free to use for 1 site and 20 SMS.

Piwik

Piwik is a free, open-source, real-time analytics program that you can install on your own server. A great alternative to Google Analytics if you want to keep the data on your own server.

Firebug

Firebug is web browser development tool that allows you to inspect HTML and modify style and layout in real-time, debug JavaScript, analyze network usage and performance, and much more! A must have for any web developer.