100% Private
Your JAR files are processed locally in your browser. We never upload or store your files.
100% local browser tool
Online JAR Viewer & File Opener
Open and inspect JAR files directly in your browser. Browse archive contents, inspect MANIFEST.MF, view classes and resources, and extract files without uploading your JAR.
✓ No upload
✓ Free to use
✓ Works in browser
JAR
Drag & drop your JAR file here
or
Your file is processed locally. Nothing is uploaded.MANIFEST.MF Viewer
Quickly check Main-Class, Created-By, Manifest-Version and other manifest metadata.
JAR Viewer & Extractor
Explore folders, preview supported files, and download selected files or the full archive contents as a ZIP.
CLASS File Support
Inspect CLASS files with Hex view. Use the Android app for CLASS decompilation to Java.
Online JAR Viewer and File Opener
Jar File Opener Online is a JAR viewer and JAR file reader that opens JAR files directly in your browser. A JAR file is a Java archive, usually a ZIP-based package that may contain Java CLASS files, resources, images, configuration files, and a metadata file called MANIFEST.MF.
This web tool is designed for quick inspection. You can select a local JAR file, browse its internal folders, view supported text files, inspect binary files in Hex view, and extract files without uploading anything to a server.
How to open a JAR file online
- Click Choose JAR File or drag a JAR file into the upload box.
- The tool reads the archive locally in your browser.
- Use the file browser to open META-INF/MANIFEST.MF, CLASS files, text files, and resources.
- Download selected files or export the archive contents.
What can this tool inspect?
- JAR file name, size, total entries, and manifest status
- MANIFEST.MF fields such as Main-Class and Created-By
- Folder structure and archive contents
- Text files such as XML, JSON, properties, MF, Java, and TXT files
- CLASS files through Hex view
Extract JAR files online
Use this JAR extractor to browse archive entries, inspect the files you need, and download individual files or export the full archive contents as a ZIP. Processing stays in your browser, so your JAR file is not uploaded to our server. Learn how to extract JAR files.
Can it decompile CLASS files?
The first web version focuses on safe local viewing and extraction. It can detect CLASS files and show Hex view. For CLASS decompilation to Java source code, use the Android version of Jar File Opener, which provides stronger offline file inspection features on your device.
Need JAR tools on Android?
Download Jar File Opener for Android to inspect JAR files on your phone, view CLASS files, and decompile supported CLASS files to Java.
Download Android AppImportant Notice
This tool is designed for opening and inspecting JAR files you own or have permission to access. Please respect software licenses, copyrights and developer terms. Online decompilation is not included in this web version.
FAQ
Are my JAR files uploaded?
No. This tool uses browser JavaScript to read your JAR file locally. Your file does not leave your device.
Can this website decompile CLASS files to Java?
The first web version supports CLASS file detection and Hex view. For CLASS decompilation to Java, download the Android app.
Can I use this as a JAR file viewer or reader?
Yes. Open a local JAR file to browse its folders and entries, read supported text files, inspect MANIFEST.MF, and preview CLASS files in Hex view.
Can I extract a JAR file online?
Yes. Browse the JAR contents and download individual entries, or use Extract All Files to export the archive contents as a ZIP. Your file stays in your browser.
Can I open JAR files on Android?
Yes. Use the Jar File Opener Android app from Google Play for a better mobile experience.