More about the 5 Best Frontend Error Monitoring Tools.
TrackJS is the best for Frontend Error Tracking with good data quality capabilities and featured plans priced lower than BugSnag. BugSnag is good if you need to correlate errors between the frontend and backend systems.
With TrackJS, the focus is on errors occurring on the browser. Filtering is second to none, and the quick views of trending errors are helpful in digging past the 3rd party script noise. It filters down to the core issues.