Want to check how your website appears around the world and also how it responds from all 7 continents and 25 geo locations, use geo-peek.com to take quick screenshots, also available Performance tools. Totally Free and unrestricted usage not even a signup needed to explore its unique features.
Browshot - Browshot is a service to take screenshot of web pages. Use any of our mobile and desktop browsers. We provide a powerful API and libraries.
GeoPeeker - GeoPeeker is a tool for viewing sites from different geographic solutions.
browserling - Live interactive cross-browser testing from your browser.
BrowserStack - BrowserStack is a software testing platform for developers to comprehensively test websites and mobile applications for quality.
Selenium - Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that.
HeadlessTesting - Headless Browser Automation in the Cloud