JSNLog

Open source JavaScript logging package that logs JavaScript errors, AJAX timeouts and other client side events in your server side log. Supports Elmah, Log4Net, NLog, Serilog, Common.Logging.

AirBrake

Airbrake is the leading exception reporting service, currently providing error tracking.

Atatus

Frontend JavaScript Contextual Error Tracking. More than just stacktrace. Get to know which user actions triggered your frontend errors.

BugSnag

Be productive - not all bugs are worth fixing. Experience best-in-class error monitoring for applications across the stack.

Errorception

Painless JavaScript Error Tracking

Raygun

Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.

Rollbar

Rollbar collects errors that happen in your application, notifies you, and analyzes them so you can debug and fix them. Ruby, Python, PHP, Node.js, JavaScript, and Flash libraries available.