Understanding ERC-20: The Ethereum Token Standard

What is ERC-20?

ERC-20 is a technical standard used for smart contracts on the Ethereum blockchain to implement tokens. This standard is widely adopted for creating fungible tokens, which are tokens that are identical and interchangeable with each other. ERC-20 defines a common list of rules that all Ethereum tokens must adhere to, ensuring compatibility and integration with various platforms, exchanges, and wallets.

Key Functions of ERC-20 Tokens

ERC-20 tokens operate through a set of mandatory and optional functions that developers must implement. These functions facilitate the creation, transfer, and management of tokens on the Ethereum network. Here are the main functions required for an ERC-20 token:

Mandatory Functions

  1. totalSupply(): Returns the total number of tokens in circulation.
  2. balanceOf(address account): Provides the token balance of a specific address.
  3. transfer(address recipient, uint256 amount): Moves tokens from the caller’s address to the recipient’s address.
  4. approve(address spender, uint256 amount): Allows an address to spend a certain number of tokens on behalf of the token holder.
  5. transferFrom(address sender, address recipient, uint256 amount): Facilitates the transfer of tokens on behalf of another address, based on the allowance mechanism.
  6. allowance(address owner, address spender): Returns the remaining number of tokens that a spender is allowed to spend from the owner’s balance.

Optional Functions

  1. increaseAllowance(address spender, uint256 addedValue): Increases the allowance granted to the spender.
  2. decreaseAllowance(address spender, uint256 subtractedValue): Decreases the allowance granted to the spender.

These functions ensure that tokens can be easily integrated and used across different Ethereum-based applications, enhancing interoperability within the ecosystem.

Advantages of ERC-20 Tokens

Standardization and Interoperability

ERC-20 tokens follow a standardized set of rules, ensuring that they can interact seamlessly with various wallets, exchanges, and decentralized applications (dApps). This standardization has led to widespread adoption and ease of integration across the Ethereum ecosystem​ .

Security and Transparency

ERC-20 tokens are built using smart contracts, which are self-executing contracts with the terms of the agreement directly written into code. This provides a high level of security and transparency, as all transactions are recorded on the blockchain and are immutable, reducing the risk of fraud and tampering​.

Ease of Development

The clear and well-defined ERC-20 standard simplifies the process for developers to create new tokens. This has lowered the barrier to entry for launching new projects and has fostered innovation within the blockchain space.

Popular ERC-20 Tokens

Several well-known cryptocurrencies are based on the ERC-20 standard. Some of these include:

  • Tether (USDT): A stablecoin pegged to the US dollar.
  • Chainlink (LINK): Used for decentralized oracles that provide external data to smart contracts.
  • Uniswap (UNI): The governance token for the Uniswap decentralized exchange.
  • Binance Coin (BNB): Originally an ERC-20 token before migrating to Binance’s own blockchain​.

Creating ERC-20 Tokens

Creating an ERC-20 token involves several steps:

  1. Writing a Solidity Smart Contract: Define the token’s behavior, including how it can be transferred and managed.
  2. Defining Token Properties: Set the token’s name, symbol, and total supply.
  3. Compiling the Smart Contract: Use a Solidity compiler to convert the code into bytecode executable on the Ethereum Virtual Machine (EVM).
  4. Deploying the Smart Contract: Deploy the compiled smart contract to the Ethereum blockchain.
  5. Interacting with the Token: Users can then interact with the token using wallets and dApps​.


The ERC-20 standard has been instrumental in the growth and development of the Ethereum ecosystem. By providing a clear framework for creating tokens, it has enabled a wide range of applications and innovations in the blockchain space. Its standardized functions and widespread adoption make ERC-20 tokens a cornerstone of the Ethereum network, fostering a robust and interoperable digital economy.

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