Libre Merger - Open-Source Automated Document Merger

A free, community-driven document tool that harnesses the full power of LibreOffice to automatically merge, split, convert, and watermark any document type you attach entirely offline, entirely free, with no subscriptions, no cloud uploads, and no proprietary lock-in. Built for developers, legal professionals, students, and anyone who works with documents.

Key Highlights

• Multi-format support merge DOCX, ODT, PDF, XLSX, PPTX, TXT, RTF, and CSV in any combination
• Watermark text & PDF password stamp a custom watermark and lock your output PDF with a password before sharing
• Flexible and manual sorting auto-sort by name or date, or fully drag-and-customize document order with per-document page limits
• Smart compression reduce output file size with quality optimized for AI attachments and fast sharing
• DOCX and PDF output choose your output format and save results into organized folders automatically
• Original PDF names preserved in outline source filenames appear as bookmarks inside the merged document for easy navigation
• Currently Windows only macOS and Linux support coming soon
• 100% free no subscriptions, no account, no hidden costs, forever

Supported Formats

Format	Extension	Support
Word Document	.docx .doc	Full
OpenDocument Text	.odt	Full
PDF	.pdf	Full
Spreadsheet	.xlsx .ods .csv	Full
Presentation	.pptx .odp	Full
Plain Text	.txt	Full
Rich Text Format	.rtf	Full
HTML Document	.html .htm	Full

Quick Setup for New Users

Step 1: Install LibreOffice (Required)

Libre Merger uses LibreOffice to process Word, Excel, and PowerPoint files. It must be installed before running the app.

Download the latest stable version for your OS:

https://www.libreoffice.org/download/download/

Run the installer and follow the default on-screen instructions. No custom configuration needed.

Verify the installation by opening LibreOffice Writer from your applications. If it launches, you are ready.

Step 2: Run the Libre Merger Installer

Once LibreOffice is confirmed working:

1. Navigate to the dist/ folder in this project directory
2. Locate the file named Setup.exe
3. Double-click Setup.exe to launch the installation wizard
4. Follow the prompts — the installer will create:
   • A Desktop shortcut
   • A Start Menu entry

Windows SmartScreen Notice: If Windows shows a security warning, click "More info" then "Run anyway". This is standard behavior for open-source unsigned installers.

Step 3: Start Merging

1. Open Libre Merger from your Desktop or Start Menu
2. Drag and drop your documents into the application window
3. Arrange the file order if needed
4. Click Merge to generate your combined document
5. Choose your output location and format

For Developers Build from Source

Prerequisites

Tool	Version	Download
Python	3.x	python.org
LibreOffice	7.x or higher	libreoffice.org
pip	Latest	Included with Python
Git	Any	git-scm.com

Step 1: Clone the Repository

git clone https://github.com/uzairshahidgithub/libre-merger.git
cd libre-merger

Step 2: Install Dependencies

pip install -r requirements.txt

Step 3: Run in Development Mode

python main.py

Step 4: Build the Installer

Run the automated build script to generate Setup.exe inside dist/:

python build.py

Troubleshooting

LibreOffice not detected: Open config.json and set the path manually:

{
  "libreoffice_path": "C:\\Program Files\\LibreOffice\\program\\soffice.exe"
}

On Linux / macOS:

which libreoffice

Setup.exe blocked by Windows Defender: Click More info → Run anyway. The full source code is auditable in this repository.

Merged PDF has missing fonts: Ensure all fonts used in source documents are installed on your system. LibreOffice uses locally installed fonts for rendering.

Slow performance on large batch merges: Split documents into smaller groups, merge each group separately, then merge the outputs together.

Compatibility

• Windows 10 / 11
• macOS — Coming Soon
• Linux — Coming Soon
• Python 3.8 — 3.12
• LibreOffice 7.x — 24.x
• No WSL required
• No internet connection required

Security

• 100% offline processing
• No cloud uploads of any kind
• No telemetry or analytics
• No account or login required
• Full open-source — entirely auditable
• Safe for confidential and enterprise documents

License

Free to use, modify, and distribute under the MIT License. Ideal for developers, students, legal professionals, SOC teams, and enterprise document workflows.

References

• LibreOffice Official Documentation
• LibreOffice CLI / soffice Parameters
• python-docx Documentation
• PyPDF2 Documentation
• PyInstaller Documentation

❤️ Credits

Developed by Muhammad Uzair Dedicated to providing free, open-source productivity tools for everyone.

Support

For support, email uzairrshahid@gmail.com or join our Discord Community Codemo Teams.