The amount of data and the importance of simple, scalable and fault tolerant architectures for processing the data keeps increasing. Big Data being a highly influential topic in numerous businesses has evolved a comprehensive interest in this data. The Lambda as well as the Kappa Architecture represent state-of-the-art real-time data processing architectures for coping with massive data streams. This paper investigates and compares both architectures with respect to their capabilities and implementation. Moreover, a case study is conducted in order to gain more detailed insights concerning their strengths and weaknesses.