If you’ve ever bought anything other than Bitcoin, you’ve almost certainly dealt with an ERC-20 standard token. SHIBA, LINK, UNI, and the stablecoins USDT and USDC on Ethereum are all built on this foundation. But ERC-20 isn’t just a buzzword. It’s a technical specification that transformed Ethereum from just “another coin” into a global financial computer.
Let’s break down, without being boring, what it is and why this seemingly dull set of rules is worth billions of dollars.
What is ERC-20, really?
The main thing to understand is: ERC-20 is not a token. It’s a set of instructions for creating tokens.
Imagine you want to issue your own digital assets. ERC-20 (Ethereum Request for Comment #20) is a universal technical standard, like GOST or ISO, which describes what basic functions your token must possess for the entire Ethereum ecosystem to understand it.
It’s like the USB standard. Any USB flash drive will fit into any computer with a USB port. Similarly, any ERC-20 token will be automatically compatible with any wallet (MetaMask, Trust Wallet), decentralized exchange (Uniswap), or lending protocol (Aave) on the Ethereum network. Developers don’t need to write unique code for each new asset.
This universality sparked a revolution.
Anatomy of the Standard: 6 Commands That Changed the World
The magic of ERC-20 is contained in a set of six mandatory functions written into its smart contract. Understand them, and you’ll understand how all of DeFi works.
Basic Functions (simple and clear):
- totalSupply — Find out how many tokens have been issued in total.
- balanceOf — See how many tokens are in a specific wallet.
- transfer — Simply send tokens from one address to another.
The next two functions are the engine that powers the entire decentralized financial system.
Interaction Functions (DeFi Magic):
- approve — This command allows you to give permission to another address (for example, the Uniswap exchange smart contract) to spend a certain amount of your tokens. You don’t send tokens; you merely grant permission for them to be used.
- transferFrom — This function allows the smart contract, having received permission, to withdraw the approved amount of tokens from your wallet.
- allowance — Check how many tokens a smart contract is still allowed to spend from your address.
When you swap USDT for ETH on Uniswap, this is exactly what happens: you first `approve` the Uniswap contract to deduct your USDT, and then the contract uses `transferFrom` to take them and send you ETH in return. Without this linkage, there would be no automated exchanges, no farming, and no staking.
Why did ERC-20 become king?
Three simple, yet powerful reasons:
- Ethereum’s Network Effect. Ethereum was the first and remains the largest and most time-tested platform for smart contracts. Everyone started building here, which attracted more users, which attracted even more developers.
- Security. Your small token is protected by the full power of the decentralized Ethereum network with thousands of validators. Hacking an individual ERC-20 token is virtually impossible without hacking all of Ethereum.
- Low Barrier to Entry. You can launch your own ERC-20 token in literally half an hour with basic programming skills. This triggered the ICO boom in 2017-2018 and continues to fuel thousands of new projects today.
The Price of the Royal Crown: The Main Drawback
Everything has a price. The cost of ERC-20’s security and popularity has been gas fees.
Any operation with an ERC-20 token is a transaction on the Ethereum network, for which you have to pay. During periods of high network congestion, the cost of a simple transfer or swap can reach $50-$100 or more. This makes small operations meaningless and excludes a huge portion of the audience.
It was precisely this problem — high transaction costs — that became fertile ground for the emergence of its main competitors, such as TRC-20 and BEP-20, which offered the world the same thing, but cheaper. But that’s a completely different story.
Conclusion: ERC-20 is not just technology. It is an economic phenomenon that standardized the creation of digital assets and gave birth to a market worth hundreds of billions of dollars. Despite its drawbacks, it still remains the gold standard, and understanding it is a prerequisite for anyone who wants to seriously understand the world of cryptocurrencies.
