PhyML (Phylogenetic inference using Maximum Likelihood) is an algorithm and a software created in 2003 by Stephane Guindon and Olivier Gascuel. It implements a fast heuristic algorithm to build phylogenetic trees from the analysis of genetic sequences in a sound statistical framework. The code of PhyML is distributed under the GNU Public Licence
It is freely available on github (https://github.com/stephaneguindon/phyml). The two articles describing the main algorithms PhyML rely on have gathered more than 15,000 citations in total. Several online services providing user-friendly web interfaces to PhyML are also available, the main one being the IFB Grand Sud bioinformatics platform (http://www.atgc-montpellier.fr/phyml/) along with that of the phylogeny.fr web site.