What Is ERC20? A Guide to the Ethereum Token Standard

By Brian Nibley · November 08, 2022 · 7 minute read

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What Is ERC20? A Guide to the Ethereum Token Standard

ERC20 refers to a standard for creating and deploying smart contracts on the Ethereum blockchain. ERC20 tokens are digitized tokens that live on that blockchain and adhere to those standards.

The Ethereum blockchain was built specifically for smart contracts, which are virtual agreements that can be programmed to execute automatically when certain conditions are met. This functionality provides for the ability to create many kinds of new decentralized applications, so many other platforms and their tokens are built on top of the Ethereum blockchain.

Quite a few of the most popular utility tokens and decentralized finance (DeFi) applications are built on Ethereum. But there are certain standards (ERC20) that developers must follow if they want their tokens to be accepted by the network.

In this crypto guide, we will answer the question, What is ERC20?, as well as how it relates to tokens issued on the Ethereum blockchain.

What Is ERC20?

ERC20 is a standard for the creation and deployment of smart contracts on the Ethereum blockchain. ERC20 tokens are a form of token that can be issued on Ethereum (and only Ethereum) that also represent a set of standards that cryptocurrencies can adhere to.

The primary purpose of ERC20 tokens is to work with smart contracts and define a common list of rules that all tokens on the Ethereum blockchain abide by.

While Ether (ETH) is the native cryptocurrency of the Ethereum network, the ERC20 token represents a specific standard — or set of rules — that developers can follow to make Ethereum-based tokens. They are, in the truest sense, the standard-bearer for the Ethereum network.

This token standard is only for fungible tokens, and not non-fungible tokens (NFTs). As such, one ERC20 token can be exchanged with another, as they’d have equal value.

ERC20 smart contracts use ERC20 tokens to facilitate transactions when its protocol calls for it. Any smart contract that utilizes transaction functionality will therefore pay the user in the form of an ERC20 token. Many popular stablecoins, like USDC and DAI, are ERC20 tokens.

Which Tokens Are ERC20?

ERC20 has enabled the creation of many new tokens. These are the 10 largest and most popular ERC20 tokens by market cap, as of September 2022:

•   Binance USD (BUSD)

•   Multi-Collateral Dai (DAI)


•   Wrapped Bitcoin (WBTC)


•   Uniswap (UNI)

•   ChainLink (LINK)

•   Cronos (CRO)

•   ApeCoin (APE)

The largest, by both trading volume and market cap, is Binance USD, a stablecoin pegged to the U.S. dollar. Stablecoins are popular among traders looking to lock in profits quickly without converting to fiat currency, as well as those seeking to earn a yield on their crypto. They aim to be more “stable,” as the name implies, than other, often volatile cryptos.

A number of decentralized finance (DeFi) and metaverse tokens are ERC20 tokens as well.

Enjin Coin (ENJ) help users perform functions or create items in video games and virtual or augmented realities. Uniswap (UNI), the native token of one of the largest DeFi platforms, allows users to borrow and lend funds to one another.

How Does ERC20 Work?

ERC20 is a standard protocol, not a program or piece of software. The ERC20 protocol governs the creation of new tokens, ensuring that they meet the required technical specifications. If a token doesn’t conform to the appropriate technical standards defined by ERC20, it won’t fit the definition of an ERC20 token, and therefore, won’t be issued on Ethereum.

It may help to think of ERC20 as similar to HTTP, the Hypertext Transfer Protocol used for websites. HTTP defines how messages on the internet are formatted and transmitted, and how servers and browsers should react in response to various commands.

Similarly, ERC20 specifies the essential features that Ethereum-based tokens should have and how they should function. Tokens that don’t comply cannot be issued, traded, or listed on exchanges.

The ERC20 Standard

Smart contracts that want to use ERC20 tokens have to follow the appropriate ERC standards. There are currently nine rules in total, and six of them are mandatory. The other three are optional. These include:

Mandatory rules

Optional rules

Allowance Token Name
Approve Decimal (Max: 18)
TransferFrom Symbol

Here’s a brief rundown of how the mandatory standards apply to the creation of tokens.

TotalSupply: Outlines the total number of tokens to be created.

Approve: Helps to eliminate the possibility of counterfeit tokens being created by requiring approval of smart contract functions.

BalanceOf: Allows users to check their balances by returning the total number of tokens held by an address.

TransferFrom: Allows for the automation of transactions when desired.

Transfer: Allows for the transfer of tokens from one address to another, like any other blockchain-based transaction.

Allowance: When a smart contract wants to execute a transaction, it has to be able to see the balance held by the Ethereum wallet trying to transact. The allowance function allows the contract to carry out the transaction if the user has sufficient balance or cancel the transaction if they do not.

These six rules must be programmed into a token for it to be considered ERC20. Without clear instructions for these rules or standards, the token wouldn’t be able to interact with smart contracts effectively, which could cause numerous issues.

History of ERC20

“ERC20” actually stands for “Ethereum Request for Comments 20,” and was first proposed by Fabian Vogelsteller, a blockchain developer and programmer, back in 2015. At the time, it was a proposed standard that outlined common rules that could be implemented into the Ethereum network, mostly with the goal of ensuring that new projects or coins would function correctly when utilized on it.

That goal ultimately came to fruition, as the standards were adopted by the Ethereum network officially in 2017. Since then, ERC20 has served as a guiding light for Ethereum developers.

The Importance and Impact of ERC20

The ERC20 standard made many initial coin offerings (ICOs) possible in recent years, and the standard makes it easy for developers to create decentralized applications (dApps) on Ethereum.

To be more explicit, the standard makes implementing new tokens simpler for developers of decentralized applications (dApps) since there is a standard protocol to follow. ERC20 tokens can be made to offer high liquidity, and smart contract transactions are thought to be low-risk if the programming is done correctly.

How to Store ERC20 Tokens

To hold ERC20 tokens, users need an ERC20 wallet, as with any other crypto. But what’s important is to make sure that the crypto wallet in question supports tokens of this nature. Fortunately, some wallets have been specifically designed for the purpose of storing ETH and ERC20 tokens, including:

•   MetaMask

•   MyEtherWallet

•   Trust Wallet

•   Mist Wallet

•   Atomic Wallet

Wallets like these can also be used to interact with other blockchain-based platforms, such as DeFi apps and NFT marketplaces.

Remember, though, that when storing crypto in any wallet, it’s generally considered good practice to back up your private keys and seed phrase. Giving someone else access to your keys or phrase could allow them to take ownership of all the crypto in that wallet.

The Takeaway

ERC20 represents a set of standards and rules used on the Ethereum blockchain, and is also used for the creation of tokens issued on Ethereum. Many popular utility tokens are also ERC20 tokens, a list that includes Basic Attention Token (BAT), Shiba Inu (SHIB), and Crypto.com Coin (CRO).

The important thing to know about ERC20 is that it provides a set of standards on the widely-used Ethereum network. That, in some ways, helps the crypto space self-manage and continue to operate efficiently.


What is an ERC20 wallet?

An ERC20 wallet is a crypto wallet that is either compatible with, or specifically designed to hold and secure ERC20 tokens. There are numerous ERC20 wallets on the market, and they may come in a variety of forms, such as hardware, mobile, or desktop wallets.

What’s the difference between ETH and ERC20?

ETH, or “Ether,” is the native cryptocurrency of the Ethereum network, and is used to facilitate transactions on the Ethereum blockchain. ERC20 is the protocol standard for creating Ethereum-based tokens, which can be utilized and deployed in the Ethereum network.

Photo credit: iStock/fongleon356

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