Are my files uploaded anywhere?

No. Scanning, hashing, and diffing all happen locally in your browser via Web Workers. Nothing is sent to any server.

How does it detect that a file was modified?

Files paired by relative path are first compared by size. If sizes match, both files are hashed with SHA-256 and the hashes are compared, so results are content-accurate.

Why are some files marked as not compared?

Browsers cannot stream-hash files, so same-size files over 100 MB would need to be loaded fully into memory. Folder Diff marks them honestly as not compared instead of guessing.

Folder Diff

Compare two local folders and see which files were added, removed, or modified — with line-level diffs for changed text files. 100% in your browser, no upload.

Text Processing/folder-diff

All processing happens locally in your browser — nothing is sent to any server

Folder A (Original)

Folder B (Modified)

Include ignored items (.git, node_modules…)

Folder Diff is a free online tool that compares two local folders directly in your browser, listing every file as added, removed, modified, or identical, with line-level diffs for modified text files. No files are ever uploaded.

What is Folder Diff?

Folder Diff pairs the files of two folders by relative path and tells you exactly what changed between them. Files that differ in size are flagged instantly; same-size files are verified byte-for-byte with SHA-256 hashing, so renamed timestamps or copied files never cause false positives.

Everything runs locally in your browser using the Web Crypto API and Web Workers. Your files never leave your machine — there is no upload, no server, and no account.

Common Use Cases

Verify a backup: compare the backup folder against the original to confirm nothing is missing or corrupted.

Audit a release: compare two versions of a project or extracted archive to see exactly which files changed.

Clean up duplicates: find which files in two similar folders are actually identical before merging them.

How to Compare Two Folders

1
Select both folders
2
Review the result list
3
Drill into modified files

Frequently Asked Questions

Related Tools

Text Diff File Checksum Text Hashing