The “Peer Community in” (PCI) is a non-profit scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field (i.e. unpublished articles deposited on open online archives like arXiv.org and bioRxiv.org). To a lesser extent, they may also recommend postprints (i.e. articles already published in journals). These specific communities are entitled Peer Community in X, e.g. Peer Community in Evolutionary Biology (PCI Evol Biol), Peer Community in Ecology (PCI Ecol), Peer Community in Paleontology (PCI Paleo) etc ... Once recommended by one or several of these PCIs on the basis of rigorous peer reviews, preprints become valid references and may be considered to be articles of high value. Recommended preprints can be used by scientists and cited in the scientific literature. There is no need for these recommended preprints to be submitted for publication in classic journals (although they can be, according to the authors’ preferences).