BlueTrace is an open-source application protocol that facilitates digital contact tracing of users to stem the spread of the COVID-19 pandemic. Initially developed by the Singaporean Government, BlueTrace powers the contact tracing for the TraceTogether app. Australia and the United Arab Emirates have already adopted the protocol in their gov apps, and other countries were considering BlueTrace for adoption. A principle of the protocol is the preservation of privacy and health authority co-operation.