DeFi is not just a buzzword in the world of cryptocurrencies. It is a fundamental shift in how humanity thinks about money, trust, and the banking system.
Decentralized Finance is a set of financial instruments and services built on blockchain, where there are no intermediaries, no banks, and everything is controlled by code.
If we compare traditional finance to gasoline-powered cars, then DeFi is Tesla in a world of old engines. It runs on the energy of smart contracts, not on the “fuel” of bank permissions and commissions.
However, to drive this new car, you need to understand what it is made of. Let’s look at 10 key DeFi concepts that are essential for entering this exciting world.
Gas
Gas is the fee charged for executing a transaction on the Ethereum network.
Every action on the blockchain (whether it’s transferring tokens or launching a smart contract) requires computing resources. These resources are paid for in Gwei — fractions of the main cryptocurrency, Ether (ETH).
The price of gas varies depending on network congestion. During periods of high activity, it can skyrocket tenfold. This is why alternatives have emerged — Layer 2 solutions (such as Arbitrum, Optimism, Polygon) that reduce gas costs and speed up transactions.
Example: Transferring tokens on the Ethereum network can cost $5–20, while on Layer 2 it costs only a few cents.
Smart contracts
A smart contract is the heart of any DeFi protocol. It is a program on the blockchain that executes the terms of a transaction automatically, without human intervention.
If the contract is written correctly and has been audited, it cannot be forged, deleted, or “rewritten.” This makes the system transparent and trustless — you don’t need to trust anyone, you just need to trust the code.
Example: The Uniswap smart contract allows tokens to be exchanged directly between users, without intermediaries, simply according to a pre-written formula.
Important point: A poorly written contract can become a vulnerability. There have been cases in the history of DeFi where hackers have withdrawn millions of dollars due to errors.
Liquidity Pool
A liquidity pool is a reserve of tokens locked in a smart contract to enable trading on decentralized exchanges (DEX).
Each pool consists of two tokens, such as ETH and USDC. Users who add their assets to the pool become liquidity providers (LPs) and receive rewards in the form of commissions.
Example: You add ETH and USDC to a 50/50 pool. If other users make a trade, you receive a portion of the commission.
However, it is important to remember the risk of impermanent loss, when the price of one of the tokens changes and your income becomes less than if you had simply held the tokens.
APY — Annual Percentage Yield
APY (Annual Percentage Yield) shows how much interest an investor receives per year, taking into account interest capitalization.
The higher the APY, the greater the potential income, but also the higher the risk. In DeFi, APY can reach hundreds or even thousands of percent, especially on new, risky protocols.
Liquidity Mining
Liquidity mining is a way to earn money by providing liquidity.
Users lock their tokens in smart contracts, and the protocol rewards them with new project tokens. This stimulates network growth and user activity.
Example: You add liquidity to the Uniswap pool and receive not only a commission but also a UNI governance token.
However, keep in mind that liquidity mining is a growth tool for startups. It can be temporary, and the price of the reward token can be extremely volatile.
Yield Farming
Yield farming is the art and strategy of maximizing profits from your assets.
Farmers “transplant” their funds from one protocol to another in search of the most profitable APY. This requires experience, constant monitoring, and a clear understanding of the risks.
Farmers always consider:
- Entry/exit fees
- The security level of the smart contract
- The possibility of scams or token dumping
- The risk of the pool drying up during a mass withdrawal of funds
Example: An experienced farmer can earn 100% per annum, but lose everything if the smart contract is hacked.
Wallets
A wallet is your interface with the world of DeFi.
Let’s break down the types:
- Non-custodial wallets — you control your private keys (MetaMask, Trust Wallet).
- Custodial — keys are stored by a third party (exchanges, applications).
- Hardware wallets — physical devices for secure storage (Ledger, Trezor).
- Web3 wallets — browser extensions for quick connection to DEX.
Smart contract wallets — decentralized accounts with additional logic (Argent, Gnosis Safe).
The main rule of DeFi: “Not your keys, not your coins.”
Stablecoins
Stablecoins are cryptocurrencies whose price is pegged to stable assets, most often the US dollar.
They are needed to protect against volatility and serve as a bridge between traditional money and DeFi.
Types of stablecoins:
- Fiat-backed — backed by dollars in accounts (USDT, USDC).
- Crypto-backed — backed by other cryptocurrencies (DAI).
- Algorithmic (unbacked) — use algorithms to stabilize the price (high risk, example — the failure of TerraUSD).
Flash Loans
Flash loans are a unique invention of DeFi.
These are instant loans without collateral that must be repaid in a single transaction.
If the borrower does not return the money before the end of the block, the transaction is simply rolled back. This mechanism is ideal for arbitrage, refinancing, and liquidations.
Example: A trader takes out a flash loan, makes a profitable trade on another DEX, repays the loan, and keeps the profit. All this happens in seconds.
DAOs and governance tokens
Although DAOs are not always included in basic concepts, DeFi would not be possible without them. A DAO (Decentralized Autonomous Organization) is a form of protocol governance through tokens. Token holders can vote on updates, fees, and the direction of the project.
This creates a collective form of ownership where power is distributed among users.
Conclusion: Code is the new law
DeFi isn’t just changing finance. It’s changing the principles of trust.
While traditional banks were built on human agreements and legal contracts, DeFi is built on code and mathematics.
