Here are the top 10 open source Help Desk Ticketing Systems that are free of cost, along with a brief description and their respective websites:
OTRS: OTRS is a popular open-source service management solution designed for IT service management and customer service. It offers a range of features, including ticket management, customer self-service, and reporting. Website: OTRS Community Edition
osTicket: osTicket is a web-based, open-source support ticket system that provides a simple and intuitive interface for managing customer inquiries and support requests. Website: osTicket
Zammad: Zammad is a versatile open-source help desk and customer support system. It features multichannel support, robust ticket management, and knowledge base integration. Website: Zammad
Spiceworks Help Desk: Spiceworks offers a free, cloud-based help desk system for IT professionals. It provides ticket management, asset tracking, and reporting tools. Website: Spiceworks Help Desk
MantisBT: Mantis Bug Tracker (MantisBT) is an open-source issue tracking system that can be adapted for help desk and customer support purposes. It offers customizable workflows and reporting. Website: MantisBT
Request Tracker (RT): Request Tracker is a highly customizable, open-source ticketing system. It is widely used in various industries and offers powerful automation and integration capabilities. Website: Request Tracker
Trellis Desk: Trellis Desk is an open-source customer support platform that offers ticket management, knowledge base, and email integration, making it suitable for small to medium-sized businesses. Website: Trellis Desk
Hesk: Hesk is a simple, lightweight help desk software with a focus on ease of use and customer support. It offers basic ticket management and knowledge base functionality. Website: Hesk
These open-source help desk ticketing systems cater to various needs and can be customized to fit the requirements of different organizations, while also being cost-effective.