Mantis Bug Tracker is a free and open source, web-based bug tracking system. The most common use of MantisBT is to track software defects.
License: Open Source
Flyspray is an open-source bug tracking system that is easy to set up and customizable, ideal for small to medium projects. In contrast, Mantis Bug Tracker offers a more user-friendly interface and advanced features, making it suitable for larger teams and more complex projects.