FusionReactor is described as 'Goes beyond “just monitoring”, to actively minimize server downtime and accelerate time to resolution like no other monitoring tool on the market. Cut to the chase and get to the root of your Java production application problems' and is an app. There are more than 10 alternatives to FusionReactor for a variety of platforms, including Web-based, Windows, Linux, iPhone and Self-Hosted apps. The best FusionReactor alternative is Datadog. It's not free, so if you're looking for a free alternative, you could try New Relic or Glimpse. Other great apps like FusionReactor are Dynatrace, SigNoz, AppDynamics and RapidSpike.