There is a new generation of cryptocurrencies gaining popularity; namely that of fast, feeless, minerless cryptocurrencies (I’ll use FFM for fast, feeless, and minerless from now on). At the moment, there are only a few to name, and IOTA and RaiBlocks are two of the most prominent ones at the moment. They differ quite vastly in how they implement FFM. This means they have different characteristics in how they perform, their complexity, and their robustness. I’ll go over these in the following sections.