In this chapter, we understood the most famous Ethereum token standard—ERC20. We looked into the different aspects of the standard, the function definition, and its usage, which a developer must know about. We discussed the approve() function, how front-running attacks are possible using that function, and how to protect your code against it. We also look at some of the advanced functions of the ERC20 implementations, which are not part of the standard. Many other token standards have been published; however, ERC20 is still used for basic token implementation. According to your contract architecture and requirements, you can use other token standards, but you need to ensure that the token standard at least follows ERC20 APIs as well.

In the next chapter, we will learn about the ERC721 non-fungible tokens standard, which is another popular token standard that's used for games and non-fungible items like digital crypto collectible cards.