This tutorial is straightforward; its purpose is to help web developers understand the concept behind electronic cash and to encourage them to start building electronic cash platforms right away.
For many years, we have misunderstood cryptocurrencies, banking apps, and other payment platforms by equating them with electronic cash. In reality, these systems are based on accounts where balances are maintained as digital data—essentially numbers—stored on centralized servers. What they represent is not actual "cash" but records of value held by institutions or networks.
Electronic cash, on the other hand, is fundamentally different. It is a digital version of physical cash, meaning it exists as actual data stored on your personal device—similar to how paper money sits in your wallet. Unlike bank or crypto accounts, where spending reduces a number in a database, electronic cash doesn’t involve updating server-side balances. Instead, when you make a payment, the electronic cash data is split and issued directly to the recipient. The recipient then measures and merges the received data with their own electronic cash holdings.
Whether we like it or not, the world economy is rapidly evolving into a fully digital one — it's already happening. So why not be among the developers driving this transformation, turning money into truly digital cash? The idea of electronic cash isn’t new. For decades, innovators have been working to shift the economy toward a fully digital financial system, one that doesn’t rely on centralized servers — much like how physical cash functions independently. Over the years, electronic cash has gone through many iterations, from microcontroller PCB kits that issued data via infrared to systems that stored information on magnetic recorders.
You can use any method of data issue, similar to what we used in this tutorial. For example, we issued electronic cash information via QR codes. You can also issue data over a network or the internet. However, to demonstrate the potential of this electronic system, we’ll start with offline issues. Later on, you can enhance your platform to support both offline transactions for remote areas and online issues for international electronic cash transactions.
0.1. Getting Started
0.2. Installation
0.3. Offline
1.1. Received Information