ESMARConf is a FREE, online annual conference series dedicated to evidence synthesis and meta-analysis in R. Our aim is to raise awareness of the utility of Open Source tools in R for conducting all aspects of evidence syntheses (systematic reviews/maps, meta-analysis, rapid reviews, scoping reviews, etc.), to build capacity for conducting rigorous evidence syntheses, to support the development of novel tools and frameworks for robust evidence synthesis, and to support a community of practice working in evidence synthesis tool development. ESMARConf began in 2021 and is coordinated by the Evidence Synthesis Hackathon.