The One-Sentence Answer

Decentralized finance (DeFi) is a collection of financial services, including lending, borrowing, trading, and earning interest, built on blockchain networks and governed by code instead of companies. No bank account required. No approval process. No business hours.

If traditional finance is a bank with tellers, vaults, and head office approval, DeFi is a vending machine: the rules are built in, it runs 24/7, and anyone with internet access can use it.

How DeFi Actually Works

DeFi runs on smart contracts, self-executing programs that live on a blockchain (most commonly Ethereum). A smart contract is like a legal agreement written in code: when conditions are met, it executes automatically, without anyone needing to approve or process anything.

Here's a simple example: a DeFi lending protocol might say, "If a user deposits ETH as collateral and requests a loan of less than 80% of that value in USDC, automatically release the USDC to them." That logic runs on-chain, permissionlessly, for anyone in the world.

Because smart contracts are open-source and auditable, anyone can verify exactly how a protocol works, something you cannot do with a traditional bank.

What Can You Do With DeFi?

DeFi vs. Traditional Finance: A Quick Comparison

The Real Risks of DeFi

DeFi offers genuine financial innovation, but it also comes with risks that don't exist in traditional banking. Be honest with yourself about these before putting real money in:

• Smart contract bugs: Code can have vulnerabilities. Exploits and hacks have cost DeFi users hundreds of millions of dollars. Even audited protocols get breached.
• Liquidity risk: In a market downturn, pools can dry up and slippage can be extreme. Your position might be worth far less than expected when you exit.
• Impermanent loss: When you provide liquidity to a DEX, price movements between the two tokens can leave you worse off than simply holding them.
• Rug pulls & scams: Not all DeFi projects are legitimate. Anonymous teams have launched projects, collected deposits, and disappeared overnight.
• No safety net: There is no CDIC insurance in DeFi. If funds are lost, through a hack or your own mistake, there is no recourse.
• Tax complexity: Every DeFi transaction (swap, deposit, reward) can be a taxable event in Canada. Keep meticulous records.

DeFi is not appropriate as a place to park emergency savings. Treat it as high-risk, high-education territory.

DeFi and Ethereum: Why They're Linked

The vast majority of DeFi activity runs on the Ethereum blockchain, or on Layer 2 networks built on top of it, like Arbitrum and Optimism. Ethereum's smart contract infrastructure was purpose-built for this kind of programmable money.

To use DeFi, you typically need:

1. A self-custody wallet like MetaMask (a browser extension or mobile app)
2. Some ETH to pay transaction fees (called "gas")
3. The token you want to use (e.g., USDC, DAI, ETH itself)

You connect your wallet to a DeFi app (called a dApp), approve transactions, and the smart contract does the rest. You stay in control of your private keys the whole time.

Should Beginners Use DeFi?

Honest answer: most beginners should start with centralized exchanges before touching DeFi. Here's why:

• DeFi has a steep learning curve. Mistakes (wrong address, wrong network) can be permanent
• Gas fees on Ethereum mainnet can be significant during busy periods
• The risk of scams is higher in DeFi than on regulated exchanges

A better starting path: buy crypto on a trusted exchange first, get comfortable with how wallets and blockchains work, and then explore DeFi once you understand what you're doing.

ChangeNOW is a great starting point: swap ETH and other assets instantly with no account or KYC required. Once you hold ETH in a self-custody wallet, you can begin exploring DeFi protocols at your own pace.

Key DeFi Terms to Know

• Smart contract: Self-executing code on a blockchain that defines the rules of a protocol
• dApp: Decentralized application: a website or app that interacts with smart contracts
• Liquidity pool: A pool of tokens locked in a smart contract to enable trading on a DEX
• TVL (Total Value Locked): The total amount of assets deposited across DeFi protocols: a measure of the ecosystem's size
• Gas: The fee paid to Ethereum validators to process your transaction
• Wallet address: Your public identifier on the blockchain: like an account number, but controlled by your private key
• Yield farming: Moving capital between DeFi protocols to maximize returns
• APY: Annual Percentage Yield: the annualized return including compounding