Azure Application Insights

Application Insights is aimed at the development team, to help you understand how your app is performing and how it’s being used. It monitors:

Request rates, response times, and failure rates – Find out which pages are most popular, at what times of day, and where your users are. See which pages perform best. If your response times and failure rates go high when there are more requests, then perhaps you have a resourcing problem.
Dependency rates, response times, and failure rates – Find out whether external services are slowing you down.
Exceptions – Analyze the aggregated statistics, or pick specific instances and drill into the stack trace and related requests. Both server and browser exceptions are reported.
Performance counters from your Windows or Linux server machines, such as CPU, memory, and network usage.
Diagnostic trace logs from your app – so that you can correlate trace events with requests.
Custom events and metrics that you write yourself in the client or server code, to track business events such as items sold or games won.