Jitbit Helpdesk

Jitbit offers hosted help desk, help desk system, and live chat services. In particular, Jitbit Helpdesk is a great widely-used support ticketing system. Developers can use it in the cloud OR install it on their own server. The endpoint URL is the hosted one, change "subdomain" to account's subdomain. The API allows getting tickets from the app, closing, replying to tickets, and attaching files.