LibreOfficeKit Converter Plugin

A Flutter plugin that uses LibreOfficeKit to convert office documents directly on the device.

It allows you to transform DOC(-X), XLS(-X), PPT(-X) and many other formats into PDF (default) or another supported export format without external services, without internet, fully offline.

What is LibreOfficeKit?

LibreOfficeKit (LOK) is the API of LibreOffice that can load and export documents programmatically.

This plugin packages LibreOffice and exposes LibreOfficeKit as a simple Flutter API.

LibreOffice version

Platform builds are based on the following LibreOffice versions:

  • Android → LibreOffice 26.8
  • iOS → LibreOffice 24.8

Features

  • Convert documents fully offline
  • No Cloud / no upload
  • Works with many formats supported by LibreOffice
  • Simple API
  • Custom export filters supported

Supported conversions

Anything that LibreOffice itself can open and export.

Common examples:

  • DOC / DOCX → PDF
  • XLS / XLSX → PDF
  • PPT / PPTX → PDF
  • ODT / RTF → PDF
  • and many more

If LibreOffice can do it on desktop, LOK can do it here.

Installation

Add the dependency in pubspec.yaml.

dependencies:
  libre_office_kit_converter_plugin: ^x.y.z

API

init()

Initializes LibreOfficeKit.

Must be called once before any conversion.

Internally this boots the LibreOffice runtime, loads fonts, registries and prepares the engine.

await converter.init();

convert()

Converts a document into another format.

Parameters

Name Required Description
filePath yes Path to input document
outputFormat no Target format. Default: pdf
outputFilePath no Full-path for output file
outputFileName no Override file name (but with default path)
filterOptions no LibreOffice export filter string

Returns

Path to the produced file.

Important drawbacks

Single document at a time

LibreOfficeKit is not designed for parallel conversions in the same process.

If you start multiple conversions simultaneously, for example using Future.wait(), the documents will still be processed sequentially.

Application size

LibreOffice is huge.

Expect the final application size to grow by ~600 MB depending on ABI and packaging strategy.

This is the price for fully offline document rendering.

Startup time

Initialization may take noticeable time because fonts, configuration and registries must be loaded.

It is recommended to call init() early.

TODO / Roadmap

  • Ability to replace bundled compiled LibreOffice sources with custom builds
  • More detailed error reporting

When should you use this plugin?

Good if you need:

  • offline conversion
  • no dependency on cloud services
  • maximum format compatibility

Bad if:

  • app size is critical
  • you need parallel conversions
  • you only convert a very small subset of simple formats

License

LibreOffice core is licensed under MPL

Libraries

libre_office_kit_converter_plugin