HelpScout - Help Scout is a simple, straightforward way to provide excellent support

statuspage - A simple self-hosted status page site with an API written in Django under the BSD license.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

UptimeRobot - Free Website Uptime Monitoring

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

StatusPage.io - StatusPage.io is the best way for web infrastructure, developer API, and SaaS companies to get set up with their very own status page in minutes. Integrate public metrics and allow your customers to subscribe to be updated automatically.