The Liblouis software suite provides an open-source braille translator, back-translator and formatter for a large number of languages and braille codes. It is a set of libraries designed for use in any of a number of applications, both free and commercial. It is written in C so that it does not require a runtime environment and hence can be used in applications written in high-level languages such as Java and Python.


04 Jun 2018 Liblouis Release 3.6.0

This release contains the usual assortment of braille table improvements, cleanups and bug fixes. The most prominent change is the refactoring of the call APIs by Bert Frees that makes the code much more manageable and solid and will help us in the future to evolve the library.

05 Mar 2018 Liblouis Release 3.5.0

This release has a number of Braille table improvements, cleanups and meta data enhancements. The most prominent new feature however is probably the much improved test coverage. This has helped in tracing and fixing a number of long standing bugs.

04 Dec 2017 Liblouis Release 3.4.0

This release brings together a lot of work by lots of different people. Probably the most prominent fix is the work on output positions by Bue and Bert. NVDA should benefit from this. Then there are new and massively improved tables like the Lithuanian 6-dot table by Rimas or the improved back-translation for French by Michel and André-Abush to name just a few. There are too many contributors to name them here, thanks to them all.

Braille translator and back-translator

Liblouis is an open-source braille translator and back-translator named in honor of Louis Braille. It features support for computer and literary braille, supports contracted and uncontracted translation for many languages and has support for hyphenation. New languages can easily be added through tables that support a rule- or dictionary based approach. Tools for testing and debugging tables are also included. Liblouis also supports math braille (Nemeth and Marburg).

Liblouis has features to support screen-reading programs. This has led to its use in numerous open-source and proprietary screenreaders such as NVDA, Orca, BrailleBack and JAWS. It is also used in some commercial assistive technology applications for example by ViewPlus.

Liblouis is the translator of choice for Benetech’s Bookshare, providing braille access to more than 350,000 books to members worldwide. Bookshare currently offers titles in braille in more than a dozen languages, with the ability to quickly add new languages as translation tables become available.

Liblouis is based on the translation routines in the BRLTTY screenreader for Linux. It has, however, gone far beyond these routines. In Linux and Mac OSX it is a shared library, and in Windows it is a DLL.

Liblouis is free software licensed under the GNU Lesser GPL.

Language bindings

The software has interfaces to a number of programming languages. There are known bindings to C, Python, Java and Javascript.

Braille formatter

Liblouisutdml is an open-source braille formatter. The formatting can be configured via a style sheet. By incorporating Liblouis it provides the capability of translating any XML or plain text file into properly transcribed, embosser-ready braille. This includes translation into grade two, mathematical codes, etc.

Liblouisutdml is free software licensed under the GNU Lesser GPL.

Braille production

There are two braille production systems based on Liblouis and Liblouisutdml.

BrailleBlaster, a joint project between ViewPlus Technologies, American Printing House for the Blind and Abilitiessoft, is aimed at hands-on production where every detail of the Braille is controlled via a graphical user interface.

DAISY Pipeline, backed by the DAISY Consortium, is aimed at automated, hands-off, high-volume production on the server.