INTRODUCTION Technology changes, constantly evolves and we, the users, must adapt to it. E-commerce in Spain it is growing at a very significant rate, around 20%, in 2016 it generated about 20,000 million euros only in Spain, although the figures are difficult to calculate. All this is possible thanks to technological advances and mainly due to the growth of means of payment. This is why we need to talk about Blockchain technology and effects that will have in the near future. Among this technological advance, we can highlight the blockchain technology on which some cryptocurrencies are based such as the well-known Bitcoin or Ethereum, Litecoin, etc. Although electronic commerce is very broad and great growth, we wanted to publish a blog where we talk about a very specific aspect, blockchain technology and cryptocurrencies. Cryptocurrencies have a variety of uses, from being a means of payment to being able to invest or even make Trade with them. We see that more and more companies accept these currencies as a means of payment, thus increasing the value and confidence of these currencies. We are experiencing a very strong appreciation of the most important currencies, even some analysts call it Currencies as a "safe haven" to diversify our investments in a situation of high uncertainty. As you know, before investing or using these currencies, whose price is usually very variable (volatile), we need to know what your "basics" would be, d. H. What technology are they based on, why are they accepted in companies, what economic effects that they can have, the security that they have and many questions that we are trying to answer in these instructions. This guide was created to spread knowledge about cryptocurrencies, as well as the technology behind them and their uses. In addition to the interesting thing about these novel tools, we need to know how they work before using or investing in them. Below we can read some questions answered by David Lanau, Blockchain Consultant. Data analyst and Director of Nodalblock