Open Source Software



Free and Open Source Software is software released under licences that allow users of the software to use it, study its source code, re-distribute it and share improvements made to it. CERN has long served as a hub for the development of collaborative software for the high-energy physics community and beyond. Modern tools have allowed this development process to evolve towards true open source software with contributions from the worldwide community. CERN also serves as the host for the development of software for many of the experiments.


Goals at CERN (as stated in CERN's Open Science Policy)

CERN software is made available as open source wherever possible, applying a license approved by the Open Source Initiative (OSI). CERN handles its research-related software as an integral part of its research products. Analysis of the CERN experiments’ physics data must be possible with open-source software. CERN’s software expertise should be shared with other science disciplines. Software development processes are expected to follow best practices. CERN contributes to open-source software relevant to its mission through code contributions, participation in the evolution of software, and standardisation.


Services and activities

CERN has established the Open Source Programme Office to support the CERN community and external organisations dealing with Open Source Software.

Internally, the OSPO provides the following services:

  • Consult, advise and train CERN’s community on best practices, tools, licences, developments, etc. for Open Source projects; 
  • Provide recommendations for open-sourcing software;
  • Advise on questions and develop guidelines regarding contributions to non-CERN Open Source projects; 
  • Provide guidelines and best practices for the technical aspects of sharing code and designs, e.g. where to host, what services to use, appropriate use of CERN infrastructure, general tooling for Open Source such as licence compliance checks and how to set up testing; 
  • Facilitate due diligence for Open Source dissemination;
  • Identify and track where and how Open Source software is used through a centrally maintained inventory, in particular for critical services; and
  • Advise CERN management on Open Source matters with impact on the organisation.

Externally, the OSPO provides the following services:

  • Provide a public catalogue of CERN’s Open Source that is easily accessible from the OSPO website; 
  • Guide interested external parties to opportunities, projects and experts at CERN through the public catalogue, events, external communication, website etc.;
  • Support external inquiries to CERN’s management related to Open Source.


Key contacts at CERN