I built BuildDiff — a free tool to compare software builds in your browser

Today, October 8, 2026, I released the first public version of BuildDiff!

BuildDiff started from a fairly simple problem: when you're working on a software project, it can be useful to know exactly what changed between two builds or folder versions.

Instead of manually going through their contents, BuildDiff lets you select two folders and compare them recursively.

It reports:

• Added files and folders.
• Removed files and folders.
• Changed file contents.
• Unchanged entries.
• Basic file and folder movements.

You can also copy the results or download them as a plain-text report.

Privacy was an important part of the design. The folder comparison itself happens locally in your browser. Your selected files and comparison results aren't uploaded to BuildDiff's backend.

The first version is completely free, doesn't require an account, and primarily targets desktop Google Chrome.

It's deliberately a Minimum Useful Version. I want to find out whether developers genuinely find this useful before deciding what to build next.

Try it here: https://builddiff.dev5942b.workers.dev/

I'd be interested to hear how you normally compare builds, whether this would help your workflow, and what you think of the current version.

showdev #webdev #devtools #gamedev

Comments

[Launch Gate]

For the "basic movements" result, I'd add a duplicate-content fixture: old folder has a.txt and b.txt with identical bytes; new folder has b.txt and c.txt, still identical. Then change b.txt while moving a copy elsewhere.

That checks whether a reported move is a unique match or just one plausible pairing of removed/added files. Keeping ambiguous candidates separate from definite movements would make the plain-text report safer to act on, while still showing every added/removed path. What evidence does BuildDiff currently use for movement matching? I haven't run it; this is a suggested fixture from the recursive comparison and movement features in the post.

[Dev5942-B]

Thanks for the suggestion!

Just to clarify, BuildDiff doesn't maintain file history. It compares two selected folder snapshots and identifies differences based on their paths, structure, and contents.

For individual file movements, it currently checks the filename, size, SHA-256 hash, and actual contents. If multiple matching candidates exist, it chooses a pairing deterministically, so you're correct that a movement can be inferred rather than definitively proven.

Rename detection isn't currently implemented either. For example, renaming a.txt to c.txt would be reported as a.txt being Removed and c.txt being Added, even if their contents were identical.

BuildDiff is still in its initial Concept Approval period, so I'm currently gathering feedback to see whether further development is justified. If the project continues, rename detection and better handling of ambiguous movement matches would be worthwhile improvements to consider.

I appreciate the suggested test case. Thanks for taking the time to look into it!