OGEE is an Online GEne Essentiality database. Gene essentiality is not a static and binary property, rather a context-dependent and evolvable property in all forms of life. In OGEE, we collect not only experimentally tested essential and non-essential genes, but also associated gene properties that contributes to gene essentiality. Note from the FAIRsharing team: we have classified the status of the resource as 'uncertain' because access to this resource appears to be insecure. We are making every effort to engage with the resource owners to understand if it is a temporary issue or if the resource is no longer active.