Most commercial defect-tracking software vendors charge enormous licensing fees. Despite being “free”, these open source defect tracking systems have many features its expensive counterparts lack.

1. Bugzilla

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.

2. Trac

Trac is an enhanced wiki and issue tracking system for software development projects. Trac uses a minimalistic approach to web-based software project management.

3. Redmine

Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.

4. BugTracker.NET

BugTracker.NET is a free, open-source, web-based bug tracker or customer support issue tracker written using ASP.NET, C#, and Microsoft SQL Server. It is in daily use by thousands of development and customer support teams around the world.

5. Eventum

Eventum is a user-friendly and flexible issue tracking system that can be used by a support department to track incoming technical support requests, or by a software development team to quickly organize tasks and bugs.

6. Flyspray

Flyspray is an uncomplicated, web-based bug tracking system for assisting with software development.

7. GNATS

GNU GNATS is a set of tools for tracking bugs reported by users to a central site. It allows problem report management and communication with users via various means. GNATS stores all the information about problem reports in its databases and provides tools for querying, editing, and maintenance of the databases.

8. JTrac

JTrac is a generic issue-tracking web-application that can be easily customized by adding custom fields and drop-downs. Features include customizable workflow, field level permissions, e-mail integration, file attachments and a detailed history view.

9. Scarab

The goal of the Scarab project is to build a highly customizable Artifact tracking system. Standard features include data entry, queries, reports, notifications to interested parties, collaborative accumulation of comments, dependency tracking.

10. The Bug Genie

The bug genie is a user-friendly and powerful web-based (PHP5) bug tracker/bug tracking tool with features such as project management, svn integration, publishing tools, messaging, calendar +more. Ready to use out-of-the-box, all you need in one package!

11. DITrack

DITrack is a free, open source, lightweight, distributed issue (bug, defect, ticket) tracking system. It is implemented in Python and runs in UNIX (*BSD, Linux, MacOS X) and Windows environment, though support for the latter is limited. DITrack is distributed under BSD

12. Ditz

Ditz is a simple, light-weight distributed issue tracker designed to work with distributed version control systems like git, darcs, Mercurial, and Bazaar. It can also be used with centralized systems like SVN.

Ditz features a simple, clean commandline interface, a robust plugin architecture which allows for adding commands and extending model fields and ditz output, a human-editable file format, and an active developer community.

Ditz also provides static HTML generation capabilities for prod

13. MantisBT

MantisBT is a free popular web-based bugtracking system.It is written in the PHP scripting language and works with MySQL, MS SQL, and PostgreSQL databases and a webserver. MantisBT has been installed on Windows, Linux, Mac OS, OS/2, and others. Almost any web browser should be able to function as a client. It is released under the terms of the GNU General Public License .

14. phpBugTracker

phpBugTracker is a web-based bug tracker with functionality similar to other issue tracking systems, such as Bugzilla. Design focuses on separating the presentation, application, and database layers.

15. AVS – Advanced Versioning System

AVS is a free SCM software based on the main concepts provided by the most expensive alternatives available on the market place. It includes a task based file repository management system, and a bug tracking engine. AVS is released with most of its features free, while a few extended ones are restricted by a commercial licence.

16. project-open

]project-open[ is a Web-based Project Management / Project-ERP software for organizations with 2-2000 users. ]po[ integrates areas such as CRM, sales, project planning, project tracking, collaboration, timesheet, invoicing and payments.

17. MyTracker

MyTracker is tracking and collaboration system that allows users to collect, file, share, and discuss any type of information, whether it is news, a thought, bug, task, idea, document, graph and report. MyTracker is powerful, well-organized, efficient, fully customizable and easy to use.

18. eTraxis

eTraxis is a free (GPL licensed) issues tracking web-based system with unlimited number of fully customizable workflows.