Bugzilla
Bugzilla is an open-source bug tracking and testing tool. It is developed by the Mozilla project. It's released under the license of the Mozilla Public License. It is written in Perl language and supported cross-platform. It empowers individuals and groups of developers to track bugs in their products effectively. It can be used for system administration, ICT support queues, bug tracking of software and hardware, and deployment management. Bugzilla is an excellent tool, it reduces downtime, increases productivity, raises customer satisfaction, and improves communication.

Features of Bugzilla

Provide security to protect confidential information.
Provide support of integrated email capabilities.
Excellent permissions system.
Comprehensive reports and charts.
Provide support for duplicate bug detection.
Provide support for multiple database engines.

Redmine

Redmine is an open-source bug tracking project management tool. It gives the facility to their user to manage a number of projects and underlying sub-projects. Redmine is written in Ruby on Rails language and it is supported cross-platform. It supported across databases for storing data and also supported 34 different languages. The software design is similar to track software and also provides similar types of features.

Features of Redmine

It provides the time tracking functionality.
It is a flexible issue tracking system.
It provides flexible role-based access control.
Excellent Gantt chart and calendar support.
Provide multiple project support.
Supported multiple languages.
Provide the support of multiple databases.

Mantis

Mantis is another open-source issue tracking tool used for tracking software defects and bugs. It also provides a record of the user that interact and it tracked their multiple projects. It has been released under the GNU General Public License version 2. It is written in PHP and used multiple databases for storage like MySQL, MS SQL, PostgreSQL. It is also used in mobile devices. It allows source code integration to increase the functionality of this tool. It supports multiple platforms like Windows, Linux, Solaris, Mach, etc.

Features of Mantis

Comprehensive reports and charts.
Time tracking and email notification.
Provide support of multiple database management systems.
Supported for mobile devices.
Supported multiple Projects per instance.
Issue change history.