Online hate speech is a growing problem in today’s digitalised societies. Women, Black people, Jews and Roma are often targets of online hate speech. Online hate proliferates where human content moderators miss offensive content. Also, algorithms are prone to errors. They may multiply errors over time and may even end up promoting online hate. This report presents the challenges in identifying and detecting online hate. Hate of any kind should not be tolerated, regardless of whether it is online or offline. The report discusses the implications for fundamental rights to support creating a rights-compliant digital environment.