The product we wish to present is an online platform for French speaking students to assess and improve their writing skills (expression and comprehension). Users are offered 16 skills to work on, ranging from vocabulary problems to text construction and discourse elaboration, via questions of syntax and grammatical morphology. For each of these skills, a set of tests is deployed, taking the form of fill-in-the-blank texts or multiple-choice questions, which the user goes through via an algorithm that adapts to his or her level of success. A system of tutorials accompanies the user in his self-training, providing detailed explanations, including a network of dedicated educational resources, organized around short videos, each developing a solving strategy for the problem addressed. The structure of the platform is based on a skills referential that has been developed from a corpus of some 4,000 pieces of data collected from writings produced or practiced on by students. This referential integrates more than 800 abilities and mobilizes a difficulty scale established on the basis of psychometric measures founded on testing campaigns. The demonstration will show how the platform operates, with a presentation of the referential and algorithm behind it, and with a simulation of a typical user path, including his or her stages of progress, and the types of tutorials provided.