The GA4GH Beacon Specification is a web service for genetic data sharing that can be queried for information about specific alleles. It enables the secure sharing of genomic data from participants of genomic studies using Beacons web-servers that answer questions to which the Beacon must respond with yes or no, without referring to a specific individual. “Beacons” provide discovery services for genomic data in ELIXIR and the Beacon network, using the Beacon technology developed for the Global Alliance for Genomics and Health (GA4GH). The Beacon protocol defines an open standard for genomics data discovery, that provides a framework for public web services responding to queries against genomic data collections. Global Alliance for Genomics and Health provides responsible, voluntary and secure services for sharing of genomic & clinical data.