Quick answer
DeFi (decentralised finance) refers to financial services — trading, lending, borrowing, earning interest — that run on blockchains using smart contracts rather than through banks or brokers. Anyone with an internet connection and a crypto wallet can access DeFi, without accounts, credit checks, or geographic restrictions. The total value locked in DeFi protocols regularly exceeds $100 billion.
What is DeFi in simple terms?
Traditional finance involves intermediaries: banks hold your savings, brokers execute your trades, insurance companies underwrite your policies. Each intermediary charges fees, imposes requirements (credit scores, minimum balances, citizenship restrictions), and adds friction.
DeFi replaces these intermediaries with smart contracts — self-executing code on a blockchain. Instead of depositing into a bank account managed by HSBC, you deposit into a smart contract on Ethereum. Instead of trading stocks through a broker, you swap tokens directly on Uniswap. The financial logic — interest calculations, trade execution, loan management — is all handled by code.
The key properties of DeFi: permissionless (anyone can participate, no application required), transparent (all transactions and code are publicly visible), non-custodial (your funds stay in your wallet until you explicitly move them), and composable (different protocols can be combined like Lego bricks to create new products).
What can you actually do in DeFi?
- Decentralised exchanges (DEXs)
- Trade cryptocurrencies directly from your wallet without a centralised exchange. Uniswap, Curve, and dYdX let you swap tokens instantly at algorithmically-set prices. No account, no KYC, no withdrawal delays.
- Lending and borrowing
- Deposit crypto to earn interest (supply to Aave or Compound), or borrow against your crypto holdings as collateral. Interest rates adjust automatically based on supply and demand.
- Yield farming / liquidity provision
- Provide liquidity to DEX pools and earn a share of trading fees. Liquidity providers on Uniswap earn 0.01%-1% of every trade through their pool, paid continuously.
- Staking
- Lock up tokens to support network security or governance and earn rewards. Ethereum staking yields approximately 3-4% APY. Protocol staking (staking a project's governance token) can offer higher but more volatile rewards.
- Stablecoins
- Algorithmic or collateral-backed tokens pegged to fiat currencies (usually USD). DAI, USDC, and USDT are the most used. Essential for DeFi users who want to park funds without exposure to crypto price volatility.
- Derivatives
- On-chain options, futures, and perpetual contracts. Synthetix, GMX, and dYdX allow leveraged trading of crypto and even traditional assets like gold and equities without a broker.
- Asset management
- Automated strategies that compound yield, rebalance portfolios, or execute complex multi-protocol strategies automatically. Yearn Finance pioneered automated yield optimisation.
How big is DeFi?
DeFi grew from virtually nothing in 2019 to over $100 billion in Total Value Locked (TVL) at its peak in late 2021, declined sharply with the broader crypto bear market, and has re-established significant scale.
TVL measures the total value of assets deposited across DeFi protocols — lending markets, DEX liquidity pools, yield vaults, and similar. DeFiLlama, the main DeFi analytics platform, tracks hundreds of protocols across dozens of blockchains.
Key milestones in DeFi history: Compound launched yield farming in June 2020, triggering the 'DeFi Summer' boom; Uniswap's airdrop of 400 UNI tokens per wallet (worth over $1,000 at the time) to early users in September 2020; the collapse of Terra/LUNA in May 2022, wiping out $40+ billion and exposing algorithmic stablecoin risks; and the ongoing expansion across Layer 2 networks making DeFi accessible at minimal cost.
How does DeFi differ from traditional finance?
| Factor | Traditional Finance | DeFi |
|---|---|---|
| Access requirements | Bank account, credit score, ID, geography | Crypto wallet and internet connection |
| Custody of assets | Bank holds your money | You hold your crypto always |
| Transparency | Internal, opaque | All code and transactions publicly visible |
| Operating hours | Business hours, weekdays | 24/7/365 with no downtime |
| Reversibility | Transactions can often be reversed or disputed | Transactions are irreversible |
| Regulatory protection | FSCS, FCA, deposit insurance | None in most jurisdictions |
| Settlement time | 1-3 business days typically | Seconds to minutes |
| Counterparty | Bank, broker, institution | Smart contract code |
What are the risks of DeFi?
DeFi offers genuinely new financial capabilities, but the risk profile is materially different from traditional finance and in many ways more severe for ordinary users.
- 01
Smart contract risk
DeFi protocols run as code. If the code contains a bug, attackers can exploit it to drain funds. Even audited protocols have been hacked — the Euler Finance hack in 2023 lost $197M before most funds were returned; Ronin Bridge lost $625M in 2022. The more complex a protocol, the larger the potential attack surface.
- 02
No regulatory protection
DeFi sits largely outside the regulated perimeter. The FCA in the UK and SEC in the US have limited reach over decentralised protocols. There is no FSCS protection, no ombudsman, no compensation scheme if things go wrong.
- 03
Scams and social engineering
DeFi's permissionless nature makes it attractive for fraud. Fake tokens, exit scams, phishing sites, and honeypots are widespread. The FCA consistently warns that crypto is a primary vehicle for investment fraud.
- 04
Liquidation risk for borrowers
Borrowing in DeFi uses over-collateralisation. If the value of your collateral falls, your position can be automatically liquidated — you lose a portion of your collateral to repay the debt and cover a liquidation penalty. This can happen rapidly in volatile markets.
- 05
Complexity and user error
DeFi's user experience remains complex for new users. Sending to wrong addresses, approving malicious contracts, using the wrong network, and losing recovery phrases are common causes of permanent fund loss.
Frequently asked questions
Do I need a bank account to use DeFi?
No. DeFi is specifically designed to be accessible without a bank account. You need only a crypto wallet and internet access. However, to get your initial funds into crypto, you typically need a way to buy cryptocurrency — which currently often requires a bank account or card through a centralised exchange.
Can I earn passive income from DeFi?
DeFi offers multiple yield-generating activities: lending on Aave or Compound, providing liquidity on Uniswap, and staking. These can generate returns ranging from 2% to 20%+ APY depending on the asset and protocol. However, these yields come with risks — smart contract risk, liquidation risk, and impermanent loss (for liquidity providers). There is no truly 'passive' income in DeFi without accepting some risk.
Is DeFi legal?
Using DeFi protocols is generally legal in most jurisdictions including the UK and US, though regulations are evolving rapidly. Profits from DeFi are taxable in most countries. Some countries restrict access to specific DeFi front-ends. Always check the regulatory situation in your country and report DeFi income to relevant tax authorities.
What is TVL and why does it matter?
TVL stands for Total Value Locked — the total value of assets deposited in a DeFi protocol. It is the primary measure of a protocol's size and adoption. Higher TVL generally indicates more confidence from users and more liquidity for trading. DeFiLlama.com tracks TVL across all major protocols and chains.
What is impermanent loss in DeFi?
Impermanent loss occurs when you provide liquidity to an AMM pool (like Uniswap) and the price ratio between the two tokens changes significantly. Because the AMM automatically rebalances, you end up holding proportionally more of the asset that fell and less of the asset that rose. Your holdings in dollar terms may be less than if you had simply held the tokens. The 'impermanent' part: if prices return to their original ratio, the loss disappears.