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UseResponse is a fully customizable, customer feedback software and support ticketing system with open code that you can place on your server or use in cloud.It can be used as FAQ, ideas bank, bug tracking system, testimonials or all-in-one support software.4 Platforms: feedback with ideas, help desk with ticketing, knowledge base, live chat with messengers

Zammad is a web based open source helpdesk/customer support system with manyfeatures to manage customer communication via several channels like telephone,facebook, twitter, chat and e-mails. Do you receive many e-mails and want to answer themwith a team of agents?

OTRS is the leading help desk software solution that makes the communication with your clients more transparent and easier. From incidents to service requests, with the web-based Open Source help desk software, OTRS, no communication is lost and customer requests are routed automatically to the right service team, ensuring they are answered more quickly. Free of license costs and with an open and flexible architecture OTRS makes it possible for service organizations to build a customized and powerful service management solution resulting in high-quality service at minimal operational cost. Since Version 5 OTRS offers responsive design and works on any mobile device. A new chat feature including webRTC based audio and video chat, appointment calendar for improved team collaboration and resource planning plus fully encrypted messaging is now available. »

Freshdesk is an award-winning, online help desk software that allows you to support customers over email, phone, the web or even through Twitter and your company's Facebook page. With Freshdesk there is nothing to download or install, you don't have to worry about server upgrades/patches and your agents can support customers from anywhere. Popular features include:

Bugzilla is a "Defect Tracking System" or "Bug-Tracking System". Defect Tracking Systems allow individual or groups of developers to keep track of outstanding bugs in their product effectively. Most commercial defect-tracking software vendors charge enormous licensing fees. Despite being "free", Bugzilla has many features its expensive counterparts lack. Consequently, Bugzilla has quickly become a favorite of hundreds of organizations across the globe.

Help Scout scales like any other help desk, but the customer experience is personalized like a normal email.

InvGate Service Desk is a web-based ITIL-ready solution with an unprecedented user interface. Code-free config for Incident, Problem, Change, Asset & Knowledge processes. Smart ticket management, workflow automation & unmatched user collaboration.

Brimir is an open source helpdesk system. It allows you to send and receive support emails through a friendly web interface.Received emails are converted to tickets, which can be assigned to agents.

RT is an enterprise-grade ticketing system which enables a group of people to intelligently and efficiently manage tasks, issues, and requests submitted by a community of users.

Desk.com lets you see all your customers in one place and engage them across all your support channels (Twitter, Facebook, phone, email, chat and discussion boards) in one easy-to-use desktop. Be there for your customers — anytime, anywhere.

Price: FREE, Language: PHP/MySQL, Type: Web-based, Features: unlimited tickets, categories, knowledgebase, attachments and more.

Kayako is effortless customer service software that helps teams be more productive and build customer loyalty.

Jitbit HelpDesk is helpdesk software that has same price for ANY number of technicians. And it has everything a help-desk needs: 2-way email integration, asset tracking, knowledge base, file attachments and more.

Web based software for project management, issue tracking, collaboration, team calendar, kanban board and more... It is a powerful platform especially suitable for application development or product development organizations. Collaborate easily in your organization or your team or with customers.