Free online CRX to ZIP converter

Some extension tools accept ZIP archives for inspection or unpacking, while Chrome extensions are commonly distributed as CRX files. Converting the archive lets you inspect or share its contents with software that expects ZIP.

What the CRX format is

CRX is the package format used to distribute extensions for Chromium-based browsers, including Google Chrome. Extension developers create CRX packages for installation or distribution; you may also encounter them when downloading an extension file. A CRX wraps the extension’s ZIP data with a header containing version and signing information.

What the ZIP format is

ZIP is a widely supported archive format for storing and compressing files. It is useful for archiving, sharing, and opening an extension’s files with standard archive tools. Unlike CRX, ZIP does not contain the CRX package header or its signature.

How to convert CRX to ZIP

Online on 101convert.com

1. Open the CRX-to-ZIP converter on 101convert.com and upload the CRX file. You can add several files for batch conversion; the page shows the per-file size limit.
2. Start the conversion to ZIP.
3. Download the resulting ZIP file.

Offline with desktop software

Python 3, available for Windows, macOS, and Linux, can remove the CRX header without uploading the extension. Save this script as crx_to_zip.py:

from pathlib import Path
import struct
import sys

src = Path(sys.argv[1])
data = src.read_bytes()

if data[:4] != b"Cr24":
    raise SystemExit("Not a CRX file")

version = struct.unpack_from("<I", data, 4)[0]
if version == 2:
    public_key_len, signature_len = struct.unpack_from("<II", data, 8)
    offset = 16 + public_key_len + signature_len
elif version == 3:
    header_len = struct.unpack_from("<I", data, 8)[0]
    offset = 12 + header_len
else:
    raise SystemExit(f"Unsupported CRX version: {version}")

if data[offset:offset + 4] != b"PK\x03\x04":
    raise SystemExit("CRX payload does not start with a ZIP file")

out = src.with_suffix(".zip")
out.write_bytes(data[offset:])
print(f"Created {out}")

Run python crx_to_zip.py extension.crx, replacing extension.crx with the input filename. On Windows, py crx_to_zip.py extension.crx may be the appropriate command.

Quality and compatibility

This conversion copies the ZIP payload without recompressing its files, so their contents are preserved. It removes the CRX header and signature; the resulting ZIP is for inspection or archiving, not direct installation as a signed CRX. To test an extension locally, extract the ZIP and use Chrome’s Extensions → Developer mode → Load unpacked option on the extracted folder.