What is a PUB file?
The .PUB file extension primarily represents a Publisher Document. Microsoft developed this format for Microsoft Publisher, a popular desktop publishing application. These files contain page layouts, text, graphics, and formatting data used to create newsletters, flyers, and brochures.
Alternatively, a .PUB file can be a Public Key File. System administrators and developers use this format for secure authentication. Common examples include SSH public keys generated by OpenSSH or PuTTY, and Android Debug Bridge public keys used in the Google Android SDK.
How to open PUB files?
Because .PUB has multiple possible meanings, we recommend using viewer.online/pub to analyze your .PUB files to identify their exact format and creator software. It shows which programs can open the file and usually previews it.
If the file is a Publisher Document, you can open it with Microsoft Publisher or free alternatives like LibreOffice Draw. If the file is a Public Key File, you can open it with any standard text editor, such as Notepad++ or Visual Studio Code.
Best practices and troubleshooting
Sharing a Publisher Document can be difficult because not everyone has the software installed. To solve this, we recommend file conversion to sensible target formats on convert.guru. Converting your .PUB file to a .PDF or .DOCX makes it accessible to almost anyone.
For SSH keys, always ensure you only share the .PUB file (the public key) and never the accompanying private key (such as a .PEM or .PPK file).
Software and tools
- Microsoft Publisher - Primary authoring tool for layout documents.
- LibreOffice Draw - Free, cross-platform tool to open and edit layout files.
- PuTTY - Popular tool for generating SSH keys on Windows.
- OpenSSH - Command-line utility for managing network keys.
Summary
viewer.online/pub directly opens and previews .PUB files in the browser, eliminating the need to install software or troubleshoot compatibility issues.