LEOS (Legislation Editing Open Software) is an open source
software designed to help those involved in draſting legislation, which in
itself is a complex knowledge-intensive process, by supporting efficient
online collaboration. Comments, suggestions, version control, co-edition,
everything is there. Regarding the structure, that is where we aim to be
as restrictive as possible and this is not because we are conservative,
but because this helps the draſters follow the rules and avoid mistakes.
Content is stored in an XML format, currently Akoma Ntoso V3.
LEOS (Legislation Editing Open Software) is a project
under [**Interoperable
Europe**](https://joinup.ec.europa.eu/interoperable-europe) initiative of
the European Commission for a reinforced public sector interoperability
policy, funded by the [Digital Europe
Programme](https://digital-strategy.ec.europa.eu/en/activities/digital-programme
"https://digital-strategy.ec.europa.eu/en/activities/digital-programme") (DIGITAL).
The LEOS project under Interoperable Europe focuses on supporting the
co-development co-design, and co-deployment of an ‘IT eco-system centred
on augmented LEOS’.
LEOS has been created to addresses the modernisation and digital transformation of the drafting and revising of legislation in Member States, EU Institutions, EU agencies and bodies. The aim is to:

• Improve the quality of legislation.
• Increase the efficiency of the legislative process across the Union.
• Facilitate interoperability and seamless cooperation between the

different actors in the legislative process in and between EU Institutions
and Member States.

• Improve transparency and accessibility and thus effectiveness of law.
• Explore and pilot the use of innovative technologies such as Artificial

Intelligence.
It is based on the Akoma Ntoso XML format an OASIS LegalDocML standard
(in particular, it supports the
AKN4EU
interinstitutional instantiation subschema of Akoma Ntoso) that
facilitates interoperability between **Member States and EU
institutions.**
The code of augmented LEOS is available for free under EUPL licence
(version 1.2 or – as soon they will be approved by the European Commission

• subsequent versions of the EUPL (the "Licence")), and the development

team paid attention to organise the code in a structured way to ease its
reusability (modules, plugins…).
The current modules of augmented LEOS can be found on code.europa.eu
(open source project repo from EU institutions):

• LEOS core and
• Annotations utils.

For more information on the EUPL licence, please visit
this link. 
Important to note that our journey started under ISA Programme with ISA
Action 1.13. LEOS - Legislation Editing Open Software, when we first
developed a better understanding of the way public administrations address
the issue of drafting their legislations, with a view to identify best
practices, improvements and areas where common efforts and developments
are possible. We also invested time on researching the best open standards
and tools so that we could be cost efficient and deliver open source for
our community. And we keep doing this every time we need to add new
features. Having identified an opportunity in the field, the project
delivered various proof of concepts and prototypes. Now we have an
execution phase every year where we constantly improve our tool. After ISA
Action 1.13, LEOS continued under ISA² Action **2016.38 Legislation
Interoperability Tools – LegIT** until the end of ISA² Programme.