ZIP inspector
Explore ZIP filenames, declared sizes and compression methods in an interactive directory without extracting contents.
How it works & useful details
Explore file names, declared sizes and compression methods without extracting file contents.
Everything runs locally. Files are never uploaded. Maximum 16 MiB per input file, 32 MiB combined, and 1 file. Processing can be cancelled.
ZIP support covers stored and DEFLATE entries, up to 128 entries and 32 MiB declared expansion. ZIP64, encrypted, multi-disk, symbolic-link and unsafe-path archives are rejected. Names must be ASCII or UTF-8; legacy encodings and Unicode path extra fields are unsupported. Extracted downloads use unique flat names. Only selected extracted entries have their contents verified.
About this tool
ZIP inspector explores an archive’s directory: entry names, declared sizes, compression methods, and structure, without extracting file contents. It is the first step before deciding whether an archive is safe and worth opening.
The listing comes from the archive’s central directory and is read locally. Declared sizes are not proof of content, so treat the report as metadata until you extract a specific file.
How to use it
- Choose the ZIP archive.
- Browse the entry list, sizes, and compression methods.
- Look for unusual paths, excessive entry counts, or suspicious expansion ratios.
- Export the listing or switch to the extractor for selected entries.
Worked example
Inspecting a ZIP created from four small files lists 4 entries with a declared expanded size of 467 bytes, along with each entry's name, sizes, and compression method, without extracting anything. For a download from an unknown source, this is the quickest way to see what is really inside before opening it.
What to look for
- Unexpected executables (.exe, .scr, .js, .vbs, .lnk) in an archive that claims to contain documents.
- Double extensions such as invoice.pdf.exe.
- An enormous declared size compared with the archive size, the signature of a zip bomb.
- Archives with entry names containing ../ or absolute paths, which try to write outside the extraction folder, are rejected outright as unsafe.
- Hidden system files like __MACOSX/ or .DS_Store, which are harmless but show the archive was made on a Mac.
The listing comes from the archive's central directory, which is what archive programs display too. Declared sizes are what the archive claims. The ZIP extractor verifies actual contents with CRC checks when you extract.
Frequently asked questions
Does inspecting an archive extract anything?
No. It reads the directory metadata only; contents are not decompressed.
Why can the declared size differ from the real content?
Metadata in an archive is written by its creator and can be inaccurate. Verification only happens when an entry is extracted.
What are the limits?
One archive up to 16 MiB with at most 128 entries. Archives with encryption, unsafe entry names, or compression methods other than stored and Deflate are rejected with an explanation.
Is the archive extracted during inspection?
No. Only the directory at the end of the ZIP is read. File contents are never decompressed or opened.