Honeybadger
Honeybadger is a hosted monitoring service that tracks errors happening in your applications, aggregates them, and notifies you about them based on rules you define. Honeybadger gives you the insight you need to diagnose and fix application errors, faster.
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Riemann
Riemann aggregates events from servers and applications, notifies exceptions, tracks latency, collects system statistics and more, all with a powerful stream processing language
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Sentry
Automate error tracking to find and fix issues before your users even experience a crash. Sentry is open-source, real-time, and loved by 100,000 developers around the world.
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Zipkin
A distributed request tracking system, useful for micro-service and distributed architectures written in Scala
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