Bugzilla

Bugzilla is one of the oldest open source bug trackers still in active use, originally built by the Mozilla project in 1998 and still maintained today. It handles the full lifecycle of a software defect — from initial report through triage, assignment, reproduction, fixing, and verification — with a detailed status workflow, comment threads, attachments, and a complete audit trail of every state change.

The query system is where Bugzilla genuinely distinguishes itself from simpler trackers. You can build searches across any combination of fields — product, component, severity, assignee, status, target milestone, keywords, and custom fields — save them as named queries, and share them with a team. For large software projects with hundreds of open bugs across multiple components and releases, this query depth is what makes the bug database navigable rather than overwhelming.

Custom fields and configurable workflows mean Bugzilla can be shaped to match how a team actually works, rather than forcing a team to adapt to a fixed set of status labels. Severity levels, resolutions, component structures, and email notification triggers are all configurable. The Mozilla project, Red Hat, and a long list of major open source projects have run their public bug databases on Bugzilla for this reason.

The honest limitation is that Bugzilla shows its age. The interface is dense and functional but predates modern web UX conventions. The Perl stack requires either Docker to avoid dependency management pain, or a comfortable familiarity with Perl module installation. For teams choosing a bug tracker today without an existing investment in Bugzilla, MantisBT or Plane offer a more modern starting point. For teams that need Bugzilla’s specific query depth and workflow configurability, it remains a serious option.