IsDown is described as 'helps you monitor your external dependencies, catch problems before your clients, and get leverage over your competitors' and is an app. There are five alternatives to IsDown for a variety of platforms, including Online / Web-based, Android, iPhone, Android Tablet and iPad. The best alternative is IsZDown, which is free. Other great apps like IsDown are Downdetector, Downhound, StatusNotify and StatusGator.
IsZDown monitors the downtime of thousands of applications, websites, and services across the world including SAAS services, internet, phone, electricity, apps, and websites that go down and apps that aren’t working.
Downdetector monitors over 3,000 services in 25 countries including telecommunication outages (internet, phone and TV service), online banking problems, websites that go down and apps that aren’t working.