What is DeFi?

What does decentralized finance actually mean?

Traditional finance runs through companies. A bank keeps your deposit, decides whether you qualify for a loan and settles your payments during business hours. DeFi tries to replace those middlemen with software. The software is a set of smart contracts — programs stored on a blockchain that execute automatically when someone sends them a transaction.

The Bank for International Settlements (BIS) puts it in one line: DeFi is financial applications run by smart contracts on a blockchain. ethereum.org, the official information site for the network where most DeFi lives, describes it as an open alternative to the current financial system that lets people borrow, save, invest and trade.

Three ingredients make it work. A public blockchain such as Ethereum records every balance. Tokens — often stablecoins pegged to the dollar — are the money that moves around. And a self-custody crypto wallet is how you sign transactions and prove the funds are yours.

How is DeFi different from a bank or a crypto exchange?

The clearest way to see DeFi is to compare who does what. A centralized crypto exchange looks similar on screen, but behind it a company holds your coins, just as a bank holds your deposit.

The trade-off runs both ways. Holding your own funds removes the risk that a company loses or misuses them, but it moves all of the operational risk onto you: lost keys, a wrong address or a malicious approval cannot be undone by a help desk.

What can you do with DeFi?

Most activity falls into a handful of building blocks, and each has its own guide on this site:

• Swapping tokens on decentralized exchanges, where a pool of tokens and a formula replace the order book.
• Providing liquidity to those pools in return for a share of trading fees — and exposure to impermanent loss.
• Lending and borrowing against crypto collateral, explained in how DeFi lending works.
• Reading outside data such as prices through oracles, which many lending and derivatives apps depend on.

A swap shows the basic pattern every DeFi action follows:

1. Connect a wallet. The app is just a website; it can only propose transactions.

2. Approve and sign. You authorize the contract to move a specific token, then sign the trade and pay a network fee.

3. The contract executes. It takes your tokens, applies its formula and sends the other token back in the same transaction.

4. Check the result on-chain. A block explorer shows exactly what happened.

Is DeFi really decentralized?

Less than the name suggests. In a 2021 analysis, BIS economists described a decentralisation illusion: code cannot anticipate every situation, so someone must still decide on upgrades, fees and emergency fixes. They note that every DeFi platform has some centralization, usually built around holders of governance tokens, who are often the developers themselves and vote much like shareholders.

The Financial Stability Board (FSB) found in 2023 that voting power across major DeFi protocols is extremely concentrated, so in practice a few actors can propose and pass changes. The securities regulators' body IOSCO draws the regulatory conclusion: whatever the label or technology, people who offer financial products should be subject to the applicable laws, and DeFi code is not self-implementing — humans with technical access still sit behind it.

What are the main risks of DeFi?

The same features that make DeFi open also make it fragile. The FSB says DeFi inherits — and may amplify — the classic weaknesses of finance: operational fragility, liquidity and maturity mismatches, leverage and interconnectedness. On top of those sit risks specific to code: bugs, faulty price oracles and hacks. The US Treasury's 2023 risk assessment adds that many DeFi services do not apply anti-money-laundering rules, which criminals and North Korean cyber actors have exploited.

None of this means every protocol will fail, but it does mean that losses are common enough that regulators keep publishing warnings. We go through each risk, with real cases, in the main risks of DeFi, and the size figures people quote are unpacked in what TVL really measures.

What mistakes do beginners make with DeFi?

• Assuming "decentralized" means "safe" or "regulated". Usually it means neither. There is typically no deposit protection and no complaints desk.
• Signing approvals without reading them. An approval can let a contract move your tokens later; see token approvals explained.
• Chasing the highest advertised yield. Every return comes from a source — fees, borrowers or newly issued tokens — and the highest numbers usually carry the most risk.
• Ignoring network fees and price impact. On small amounts, fees can wipe out any benefit.
• Using a fake front-end. Bookmark official sites; phishing copies of DeFi apps exist.