Tokens have often been called Ethereum's "killer app". In this section, we learn about what the ERC20 token protocol is and how we can make and exchange our own tokens.
A Token-Powered Future on Ethereum - Simon de La Rouviere & Ashley Taylor, ConsenSys Media, 2015 [4 min read]
This blog post from ConsenSys gives a great overview as to what tokens are, what they can represent, and why they are useful.
ERC20 Tokens - Jordan Leigh, Decypher [18 min video]
Now that we understand what tokens are good for, let's learn how to build one. This video from Decypher.tv walks through making a brand new token from scratch conforming to the ERC20 standard.
EIP Breakdown: The ERC 223 Token Standard - Jordan Leigh, Decypher, 2017 [16 min video]
While the ERC20 Token standard took off quickly within the Ethereum ecosystem, it was not without flaws. One of the issues is that when tokens are sent to contract accounts that are not designed to handle them, these tokens are often lost forever. Dexaran (a developer) created an improvement to the Token standard to try to solve this problem. This video from Decypher TV explains this new token standard, how it works, and how it differs from the ERC20 standard.
Project 1: Create a Token - Nate Rush [Exercise]
Now let us try to build our own Token. This project from the UPenn Blockchain Club will serve as the spec to follow in creating your own token. Try to make it conform to the ERC223 standard while keeping compatability with the ERC standard as well. Please feel free to use external resources to help along the way.
Swap Protocol Q&A with Deepa Sathaye - ConsenSys Media YouTube, 2017 [30 min video]
One of the most valuable things about ERC20 token standard is the ability to design contracts that can interoperate with any token. One interesting use case for this interoperability is an on-chain exchange. In this video from Consensys Media, Deepa Sathaye explains the Swap Protocol, which allows two users to trade or "swap" different tokens.
Project 2: Create an Exchange - Nate Rush [Exercise]
Now that you've learned about the structure of the Swap protocol, let's try to build our own simple on chain token trading smart contract. In this exercise, designed by the UPenn Blockchain Club, you will use your knowledge of ERC20 and Inter-Contract Execution to create this very simplistic on-chain exchange.