Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.
Whoisology - Connected database of whois records and whois history
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.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
RootCause - Record, Replay and Reproduce JavaScript Errors
WebCargo - Optimize your workflow by offloading it to us. Useful API's with seamless integration that scale to your needs.