What is DeFi in crypto? Decentralized finance explained

DeFi, short for decentralized finance, is the name for financial services that run on a blockchain through smart contracts instead of through banks, brokers or exchanges. With DeFi you can trade, lend, borrow and earn interest on crypto straight from your own wallet, and anyone with an internet connection can use it. The catch is that nobody stands behind it: if something goes wrong, there is no bank, regulator or deposit guarantee to help you.

What is DeFi in crypto?

DeFi in crypto is a set of open financial applications, called DeFi protocols, that replace traditional financial intermediaries with code. In traditional finance, banks and other traditional financial institutions hold your money, approves your loan and keeps the records. In decentralized finance, smart contracts on a public blockchain network do those jobs automatically, following rules anyone can read.

Most DeFi apps run on Ethereum, because it was the first blockchain built for programmable contracts. Others run on networks such as Solana or on layer 2 networks that make Ethereum cheaper to use. Together they form the DeFi ecosystem, where apps can plug into each other like building blocks.

DeFi vs centralized finance

DeFi is not the same as crypto. Crypto is the digital assets themselves; DeFi is what you can do with them. It is also not the same as a crypto exchange app: when you use a centralized exchange, you are in centralized finance (CeFi), with a company in the middle that holds your coins.

How does DeFi work?

DeFi works by letting you connect a self-custody wallet to a smart contract and interact with it directly. There is no account to open and usually no identity check. You keep complete control of your private keys, and all your financial transactions are recorded on the blockchain for anyone to see.

The main DeFi applications

These are the main types of DeFi protocols:

Most decentralized exchanges use an automated market maker: instead of matching buyers and sellers, a formula sets the price based on the tokens in the pool. Lending protocols ask for more collateral than you borrow, so the loan is covered even if prices move.

DeFi also has products that don’t exist in traditional financial systems. Flash loans, for example, let you borrow without collateral as long as you repay in the same transaction. If you don’t, the whole transaction reverts as if it never happened.

An example with euros

Say you want to borrow without selling your ether. You deposit €1,000 of ETH into a lending protocol as collateral and borrow €500 of a euro or dollar stablecoin. You pay a variable interest rate. If the price of ETH falls far enough, the protocol automatically sells part of your collateral to repay the loan, and you pay a penalty on top. This is called liquidation, and it happens within minutes, at any hour, with no phone call first.

How to start: DeFi wallets and your first transaction

Getting started takes a few steps, and every step has a cost.

To get your money out, you reverse the route: withdraw from the app, send the tokens to a licensed exchange, sell them for euros and transfer to your bank account.

Why DeFi is important, and what it means for you

DeFi is important because it shows that many traditional financial services can run without centralized institutions. Anyone can use it, it is open day and night, and you can check every rule and every transaction. For people without good access to banks, it can be a way to access capital or hold stable value.

For you as an EU investor, the key point is regulation. MiCA licenses crypto companies, but services provided in a fully decentralized way, with no company in between, fall outside it. So when you use DeFi:

• No investor protection. There is no licence holder that must keep your assets separate, no complaints procedure and no compensation scheme.
• No deposit guarantee. A stablecoin in a lending protocol is not a savings account, even if it pays interest.
• Taxes still apply. In Germany, swapping one token for another usually counts as a sale for tax purposes, so active DeFi activity can create many taxable events. In the Netherlands, your tokens count towards box 3 wealth. Keep your transaction history.

Regulators are watching DeFi closely because of money laundering risks, and regulatory developments could change how front-end apps work for EU users.

The risks involved in DeFi

The risks involved in DeFi are bigger than with a licensed exchange, and some are new. Before you put money in, understand these:

• Smart contract bugs and hacks. DeFi platforms have lost large sums to code flaws and attacks, and stolen funds are rarely recovered.
• Fake apps and phishing. Scam websites copy real DeFi apps and ask you to approve a transaction that empties your wallet. Bookmark official addresses.
• Liquidation. Borrowing against volatile crypto can cost you your collateral in a sharp fall in the crypto market.
• Impermanent loss. Liquidity providers can end up with less value than if they had simply held their tokens.
• Rug pulls. Anonymous teams can launch a token, attract deposits and disappear.
• Centralized components. Many “decentralized” apps still rely on a team with admin keys, a website or a price feed that can fail.

The bottom line

DeFi replaces banks and brokers with smart contracts, giving you open, round-the-clock access to trading, lending and borrowing from your own wallet. That freedom comes without a safety net. If you want to try it, use a small amount you can afford to lose, stick to well-known protocols, and keep most of your crypto on a licensed platform or in cold storage.

Related terms

• Smart contract
• DEX
• Liquidity Pool
• Yield Farming
• Impermanent Loss