2XS (eXtra Small eXtra Safe) is a team of the LIFL laboratory of “Université de Lille”. Its research activities are focused on tools and languages for the performance and security of highly constrained devices. The team aims to provide solutions to enhance the adaptability and programmability of small devices starting from small sensors (IoT), smart cards to mobile phone. They mainly use two complementary fields: embedded operating systems and associated tools that are programming languages, formal proofs and automatic software processing and analysis. The team is directed by Pr. Gilles Grimaud and counts six permanent faculty members. The team has been involved in several national and European funded projects such as the EU CATRENE eGo project.