JWST is the largest space telescope ever built. Launched in space at the end of 2021 and in operation since summer 2022, it is the result of a partnership between NASA and the European Space Agency (ESA) and the Canadian Space Agency (CSA). It is equipped with a primary mirror of 6.2m diameter, and with 4 instruments operating all (essentially) in the infrared. Its exceptional instrumental capabilities make it the perfect tool for the atmospheric study of transiting exoplanets, including the planets discovered by our SPECULOOS project. Several members of the EXOTIC group are involved in JWST observing programs.