We’re building Haystack Code Reviewer, a tool that lays out code diffs for a GitHub pull request on an interactive canvas. Instead of scrolling through diffs line-by-line, you can view all changes in a more connected, visual format – similar to viewing a call graph. We hope this will make it easier and less cognitively taxing to understand how different changes across files work together.

For a quick overview, check out our short demo video: https://www.youtube.com/watch?v=QeOz70x0WPE. If you would like to give it a spin, head over to https://haystackeditor.dev, click the “Review pull request button” in the top toolbar, and load any pull request via URL or pick a pull request from a dropdown.

We built Haystack Code Reviewer because we found pull requests difficult to review in a pure textual format — especially when hopping between multiple files or trying to break down complex changes. Oftentimes, pull request authors would have to specifically structure their commits so that code reviews would be easier to tackle, which is a time-consuming and error-prone process. Our goal is to make any pull request easy to understand at a glance, and reduce the effort needed from both reviewers and authors to craft a good code review.

Haystack Code Reviewer works on private repositories! We have authentication to ensure that someone cannot open the server for your pull request without having access to that pull request on GitHub. For additional security, we plan to build self-hosting soon. Please contact us if you’re interested in this.

Alternatively, a completely local option would be to download desktop Haystack and then navigate to your pull request from there. This is great for trying out the feature without exposing any data on the cloud!

In the near future, we plan to:

1. Introduce step-by-step navigation to guide reviewers through each part of the changeset

2. Allow for self-hosting

We’d love to hear your thoughts, suggestions, and any feedback on our approach or potential features!