This presentation gives an overview of the Ocsigen framework, which is used in particular to develop the Be Sport social network. Ocsigen is a set a tools to develop Web sites and applications. Amongst other things, it contains js_of_ocaml, a compiler to Javascript, and Eliom, a powerful Web framework that can be used for traditional server-side Web programming, but also to develop client-server Web and mobile distributed applications, fully in OCaml, using multi-tier programming. This programming style can save a huge amount of time.