Compare two ZIP files without extracting them

1. Open both archives

Any of these three ways:

• Drag and drop. Select both ZIP files in Windows Explorer and drop them onto the Diffoniq window. Dropping a single file onto the left or right pane replaces just that side.
• Select Files dialog. Press Ctrl+O, enter one archive as the left path and the other as the right path (the File… buttons open a browse dialog), then confirm.
• Command line. Pass the two archives as the two paths:

"C:\Program Files\Diffoniq\Diffoniq.exe" release-1.0.zip release-1.1.zip

That is the installer’s path; if you use the portable ZIP, Diffoniq.exe is in the folder you unpacked it to.

2. Read the result

What you see is a folder comparison: one row per entry, left and right side by side, with the entries that exist only on one side or differ between the two. Files of equal size are checked by content in the background, so a changed file is never shown as identical just because it kept its size.

• Open a changed file. Double-click a row (or press Enter on it) and both versions are shown side by side as a text comparison. Diffoniq extracts them to temporary files for that and deletes them afterwards. Esc takes you back to the list.
• Archive inside an archive. A .zip inside the ZIP (or a .tar.gz, or any other supported format) behaves like a subfolder: open it the same way and Diffoniq lists its contents, to any depth. The header shows where you are, such as outer.zip\inner.zip\readme.txt.
• Renamed files are paired by rename detection and shown as one row, so a file that was moved or renamed between the two versions does not appear as deleted plus added.

Not only ZIP

The two sides do not have to be the same kind of archive. Diffoniq opens these formats directly, without an external archive utility:

A ZIP that was renamed to something else — data.bak, say — is still recognized by its content. Office and OpenDocument files (.docx, .xlsx, .odt, …) are technically ZIP containers, but they are deliberately treated as plain files.

Archive against a folder

Does the ZIP you are about to send match the folder it was made from? Open the archive on one side and the folder on the other. One thing to know: most archive formats store file times with a two-second resolution, so an entry can be one second off the file on disk. Turn on Ignore Time in Options > Directory Comparison… and those spurious time differences disappear; the content comparison is not affected.

From a script

The same comparison runs headless and writes a report instead of opening a window. Diffoniq is a windowed program, so from a batch file you wait for it explicitly:

start "" /wait "C:\Program Files\Diffoniq\Diffoniq.exe" /report release-1.0.zip release-1.1.zip --out changes.html --content

--out names the report file; its extension picks the format (.html, .txt or .json). --content makes the decision by file content rather than size and timestamp. Both roots are marked as archives in the report and every entry carries a [zip] marker, so the report stays recognizable as an archive comparison. The exit code tells the script what happened:

An archive inside an archive is listed in the report as one entry that differs; to see what changed inside it, open the comparison in the window. The full switch list is in the help: Comparison Reports.

Good to know

• Read-only. Diffoniq reads archives; it never writes into them. Your ZIP files stay exactly as they were.
• Damaged archives. A truncated or damaged archive is not rejected outright: Diffoniq falls back to a forward-only scan and lists every entry whose data is intact.
• Large archives. Diffoniq compares archives larger than 2 GB.
• Exclude patterns from the Select Files dialog (*.bak;tmp) work inside archives as well.

The full reference is in the help: Archives.

Try it on two of your own archives

Diffoniq runs on Windows 10 and 11, 64-bit. Every feature is available for 30 days before you decide.

7-Zip and RAR are trademarks or product names of their respective owners. Diffoniq is not affiliated with them.