=Cooperative threads Ocsigen is not using the usual preemptive threads model to handle simultaneaous requests. Instead of this, it is based on a model of //cooperative threads//. Ocsigen's cooperative threads are implemented in monadic style by Jérôme Vouillon, which makes them really easy to use. If you want to write an extension for Ocsigen or a Web site with Eliom, you must use this thread model. See [[wiki(21):|Lwt's documentation]].