Payment systems are a fundamental element of trade and have developed over thousands of years. This development continues especially in times of globalisation in the current Information Age. An increasing sales volume in the online trade requires corresponding electronic payment systems. This paper explores the requirements for electronic payment systems, focusing on the most important criteria for merchants. In addition to costs, factors such as security, user-friendliness, reliability and customer acceptance play a major role. Based on these criteria an evaluation scheme with nine categories is created. Each category is divided into a four-level NPLF scale and shows whether the requirements for a payment system are completely, largely, partially or not fulfilled. The paper focuses on analysing existing online payment systems. The most common systems are examined in more detail and an assessment of the individual categories is carried out. This paper does not include a ranking of the individual systems, as there is no optimal payment system. Before implementing a payment system, traders must consider the factors of cost, time and security. As in a magic triangle all three factors can never be fulfilled to complete satisfaction but must be adapted to the respective field of application. Nevertheless, the paper comes to a conclusion: In order to achieve a high level of customer satisfaction and thus increase profit, it is recommended to implement a broad and differentiated range of payment options.