Monorail Issue Tracker User Guide

What is Monorail?

Monorail is the Issue Tracker used by the Chromium project and other related projects. It is hosted at

Why we use Monorail

The projects that use Monorail have carefully considered other issue tracking tools and selected Monorail because of several key features:

  • Monorail is extremely flexible, allowing for a range of development processes to be used in different projects or within the same project, and for process details to be gracefully phased in and phased out over time. For example, labels and custom fields are treated very much like built-in fields.

  • Monorail is inclusive in that it allows average users to view details of how a project‘s development process is configured so that contributors can understand how their contributions fit in. And, Monorail’s UI emphasizes usability and accessibility.

  • Monorail has a long track record of hosting a mix of public-facing and private issues. This has required per-issue access controls and user privacy features.

  • Monorail helps users focus on individual issues and also work with sets of issues through powerful issue list, grid, and graph views.

  • Monorail is built and maintained by the Chrome team, allowing for customization to our processes. For example, Feature Launch Tracking.

User guide table of contents

This user guide is organized into the following chapters:

How to ask for help and report problems with Monorail itself

If you wish to file a bug against Monorail itself, please do so in our self-hosting tracker. We also discuss development of Monorail at

You can report spam issues via the “...” menu near the issue summary. You can report spam comments via the “...” menu on that comment. Any project owner can ban a spammer from the site.

A history of Monorail

The design of Monorail was insipred by our experience with Bugzilla and other issue trackers that tended toward hard-coding a development process into the tool. This work was previously part of Google's Project Hosting service on from 2006 until 2016. Several Chromium-related projects were heavy users of the issue tracker part of, and they opted to continue development work on it. Monorail launched as an open source project in 2016. currently hosts over 25 related projects, with over one million issues in the /p/chromium project alone.