js monitoring tools

Name website free service paid service
sentry https://sentry.io 10k events/month; One user $12/month; Starts at 50k events/month; Usage-based pricing; Unlimited users
rollbar https://rollbar.com 5,000rollbar events / mo $39/mo; 100,000rollbar events / mo
bugsnag https://www.bugsnag.com 7.5k event/mo $59/mon 150k event;
airbrake https://airbrake.io NA $49/mon; 25 errors/min
trackjs https://trackjs.com NA $29.99; 100k pagevies; 20 error/min;
raygun https://raygun.com NA $49/mon; 25,000 events/mon
honeybadger https://www.honeybadger.io NA $29/mon; 2 apps
errorception https://errorception.com NA $29/mon; 7500 errors/day
getappenlight https://getappenlight.com/features.html open source
opbeat https://opbeat.com 500k tranx/mon $99/mon; 5m tanx/month