After the detection of more than 4,000 exoplanets in 3,000 different exoplanetary systems, our knowledge on the physical, dynamical and chemical characteristics of these objects is still limited, especially for the transitional objects, of radius intermediate between Earth and Neptune, which dominate the exoplanetary census. For these reasons, international and national agencies prioritize facilities totally or partly dedicated to exoplanets’ characterization, like JWST, ELT or ARIEL. This thematic school will train the community in data reduction, spectroscopy, dynamics, and chemistry to analyse and interpret these future observations.