---
id: unoserver
version: "3.7"
license: MIT
license_treatment: permissive
maintenance: active
---

# unoserver — A server for file conversions with Libre Office

License: permissive · Maintenance: active · Downloads: 347.1K/mo

## What it is and what it does

Unoserver wraps LibreOffice's UNO interface to expose document conversion as a network service. Instead of spawning a new LibreOffice process for each conversion—which is slow and resource-intensive—unoserver starts one persistent LibreOffice instance that listens on a port and handles conversion requests from client scripts. This dramatically reduces CPU and memory overhead when converting many documents.

The package provides four command-line tools: `unoserver` (starts the listener), `unoconverter` (sends a document to convert), `unocompare` (compares two documents), and `unoping` (checks server status). It supports a wide range of input and output formats, filter options, and can run in daemon mode. Installation requires using the Python interpreter that LibreOffice itself uses, which the documentation helps you locate.

Use it for:

- Batch-convert hundreds of office documents to PDF in a CI/CD pipeline without restarting LibreOffice between files.
- Build a web service that accepts document uploads and returns converted PDFs or images on demand.
- Automate document format migration (e.g., XLSX to CSV, ODF to DOCX) in a long-running application.
- Compare two versions of a document and export the diff as a separate file.
- Monitor document conversion health in a production system using the `unoping` health-check command.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Unoserver runs LibreOffice as a persistent server to convert documents between formats (PDF, HTML, images, etc.) via command-line or programmatic clients, avoiding repeated startup overhead.

Yes, if you need to convert documents at scale and have LibreOffice available. The server model is a genuine efficiency win over repeated command-line invocations. Install friction is low (no Python dependencies), but you must use the LibreOffice-bundled Python, which requires upfront setup. No known vulnerabilities. Active maintenance and permissive license. Not suitable if you lack LibreOffice or cannot install packages into its Python environment.

## Install

pip install unoserver
uv add unoserver
poetry add unoserver

## Installing unoserver

Before you install: Low friction: pure Python wheel with no runtime dependencies. Requires LibreOffice itself to be installed and accessible to the same Python interpreter running unoserver; the documentation provides a helper script to locate compatible Python installations.

License in practice: MIT license permits unrestricted use, modification, and distribution in commercial and private projects with minimal obligations.

Quickstart:

# Install unoserver with the LibreOffice-compatible Python
$ /path/to/libreoffice/python -m pip install unoserver

# Start the server
$ unoserver --interface 127.0.0.1 --port 2003

# In another terminal, convert a document
$ unoconvert input.odt output.pdf --host 127.0.0.1 --port 2003

LibreOffice must be installed on the system and unoserver must be installed using the Python interpreter bundled with or used by that LibreOffice installation, not a generic system Python.

Verify before relying:

- Whether Windows and Mac support is now stable (documentation notes it was untested as of writing).
- Performance improvement magnitude (docs claim 50–75% CPU reduction but exact conditions unclear).
- Whether the package works with recent LibreOffice versions beyond what the classifiers indicate.

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 347.1K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

libreoffice document conversion server, batch convert documents to pdf, headless libreoffice automation, uno server document conversion, convert odt xlsx to pdf programmatically, document-conversion, libreoffice-automation, batch-processing

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