Files and data

What is ZIP?

Also called ZIP archive or ZIP file.

ZIP is an archive format that bundles files and folders into a single file and can compress their contents losslessly.

By Utility Mule editorial team Last reviewed September 29, 2026 How we write guides

How it works

A ZIP file is a container. Each file inside is stored as a separate entry with its name, folder path and dates, usually compressed on its own. Extracting the archive recreates the original files and folder structure exactly.

An archive makes groups of files easier to transfer while retaining separate entries. Compression savings vary with the source. Plain text, spreadsheets and uncompressed images often shrink a lot, while formats that are already compressed may barely shrink.

ZIP is also used inside other formats. Word documents, Excel workbooks, EPUB books and Android apps are all ZIP archives with a specific structure, which is why a file type checker may identify them as ZIP.

A practical example

A folder of CSV exports can be packaged into one ZIP download and extracted back into individual files later, often at a fraction of the original size.

What to watch out for

ZIP isn’t automatically encrypted and isn’t a safety guarantee. Inspect unexpected archives carefully and avoid opening untrusted extracted files.

Tools you can use

Create Zip · Bundle files or a folder into one archive
Unzip Files · Open an archive and take out what you need

Go a little deeper

Common questions

Why didn’t zipping make my photos smaller?

JPEG, PNG, MP4 and most modern formats are already compressed, so ZIP finds little left to squeeze. It still bundles them into one convenient file.

How do I open a ZIP file on a phone?

iPhones open ZIP files in the Files app by tapping them. Android’s Files app extracts them too. An online unzipper works in any browser.

Can I send a folder by email?

Not directly, but you can compress the folder into a ZIP and attach that single file, provided it stays under the email size limit.