Mantis Bug Tracker

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Pivotal Tracker

Trac is an enhanced open source, wiki and issue tracking system for software development projects. With Trac, developers and teams can manage their projects with ease and write great software in the process. Trac provides bug tracking system that ca be used by organizations building open source or proprietary software. The system impose as little as possible on team's established development process and policies, while integrating seamlessly with version control systems including Subversion and Git.

OpenProject is an open-source, web-based project management system for location-independent team collaboration. The software allow you and your team to efficiently plan, collaborate and document the process of building projects. OpenProject is released under the GNU General Public License Version 3 and is available as free community edition and a commercial, hosted, enterprise edition.

GitBucket is a free and open-source Git platform built on the JVM. GitBucket is written in Scala and released under the Apache License Version 2.0.

Backlog is an online project management software that provides a simple yet powerful interface that can be quickly adopted by anyone. Backlog allows you to with developers, clients, designers, and other teams, connected on one platform. 

nTask is a task management platform smart teams rely on to get things done better and faster. With nTask you can visualize project plans and manage resources in a better way through beautiful Gantt charts. Or make tasks dependant on each other through relationships and set and achieve project milestones by organizing tasks in the form of most significant events. nTask also provide tools so that you can effectively bill your project by hourly rate. This can be done for an entire project, individual tasks, or resources.

Codegiant is a cloud-based software platform that provides fully integrated workflow for developers. The platform provides tools for project management of software development projects, including issue tracking, hosted Git repositories, continuous integration and documentation. By providing a unified, secure platform companies can focus on building software rather than setting up tooling and infrastructure. Allowing companies and their teams to work closer and better together and shipping projects to production faster. Codegiant is free for small teams up to 5 people, after that a monthly subscription per user is required to use Codegiant in your projects.