
Prometheus
Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud.
Collect and analyze errors in JavaScript, Node.js, Python, Ruby, Java, PHP and other aplications.
rollbar collects errors that happen in your application, notifies you, and analyzes them so you can debug and fix them. javascript, ruby, python, php, node.js, android, flash, .net, and java libraries are available.
* stack trace* automatically capture uncaught errors* send deploy events to partition errors before and after a code change* source map support
the free plan supports 5000 error events per month.
Real time monitoring Web log analysis
Productivity Developer Tools Networking and Admin
real-time-monitoring crash-reporting error-reporting error-tracking web-log-analyzer