Errbit!

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.

Bugsnag automatically detects errors in your mobile, front-end, and back-end applications, and provides your team the tools to fix things fast. Bugsnag provides clear insights on the frequency and user impact of each error, so your team can make informed prioritization decisions. Replicating and troubleshooting is easier with automatically collected diagnostic data on where and how an error occurred. Over 3,500 of the world's best engineering teams from organizations like Square, Airbnb, Shopify, and others use Bugsnag to build better software. »

Airbrake collects errors generated by other applications, and aggregates the results for review.

App Enlight- provides a helpful interface to let you and your team save time spent on debugging and reproducing errors and performance problems from a production environment.

Trakerr.IO - track errors, prioritize and fix them with the next generation application intelligence platform

Apteligent (formerly Crittercism) offers tools that empower mobile devs & PMs to troubleshoot, prioritize, & resolve issues damaging their users’ app experience.

Monitor actual user JavaScript errors as they happen. JSMonitor features real-time alerts, prioritization, and tracking features to squash JavaScript errors forever.