TestingBot is an online service which provides a Selenium Grid in the cloud. By utilizing TestingBot, you have immediate access to over 600 browser and device combinations to run both Automated Selenium and Manual tests. Ranging from IE6 to Chrome dev builds, from Windows XP to Windows 10 and macOS Sierra.
If you are looking to run tests against a website you're still developing on your computer or local network, you can use the TestingBot Tunnel. This allows you to run Automated and Manual tests on websites that are not yet available to the public.
If you're still using Selenium IDE or RC, you can upload your tests and test suites to TestingBot. Then you can schedule when the tests need to run and on which browsers. After each test run, you will receive a report and you can set up alerting to be notified when a test fails.