What Is DeFi? Decentralised Finance Explained, Risks Included

DeFi, short for decentralised finance, is a set of financial applications that run on public blockchains through smart contracts, aiming to offer services like trading, lending and borrowing without a bank or broker in the middle. You connect a wallet, interact with code, and the code moves the assets. That removes some intermediaries, but it also removes most of the protections that come with them.

This guide explains what DeFi is, how it works, what people use it for, how EU rules treat it and what can go wrong. It is meant to help you understand the space, not to sell it.

Key takeaways

• DeFi is financial software running on blockchains, mostly through smart contracts, that tries to replicate services like exchange, lending and borrowing without central institutions.
• The EBA and ESMA describe DeFi as niche: in their January 2025 report, value locked in DeFi protocols was about 4% of total crypto-asset market capitalisation.
• Services provided in a fully decentralised way fall outside MiCA, which means limited or no consumer protection.
• The main risks are smart-contract exploits, stolen keys and phishing, liquidation cascades, unclear disclosures and plain loss of funds with no one to complain to.

What is DeFi?

The European Banking Authority (EBA) and the European Securities and Markets Authority (ESMA) define DeFi as "a system of financial applications built on blockchain networks that aims to replicate some of the functions of the traditional financial system in a seemingly open and permissionless way, eliminating traditional financial intermediaries and centralised institutions."

Two words in that definition do a lot of work. "Replicate" means DeFi mostly rebuilds familiar services, such as exchanging one asset for another or borrowing against collateral, in software. "Seemingly" is a regulator's hint that the openness and decentralisation are not always as complete as the marketing suggests. Many protocols have development teams, admin keys or governance tokens concentrated in a few hands.

How does DeFi work?

DeFi applications are built from smart contracts: programs stored on a blockchain such as Ethereum that execute automatically when their conditions are met. A lending protocol, for example, is a set of contracts that hold deposited assets, track who borrowed what, and sell collateral automatically if its value drops too far.

You usually reach DeFi in one of three ways, according to the EBA and ESMA: through a DeFi application's web interface, through a self-custodial wallet, or through a centralised platform or other service provider that routes you into DeFi.

With a self-custodial wallet, you hold the private keys and sign every transaction yourself. Nobody can freeze your account, but nobody can reverse your mistakes or restore your access either. If you are new to how keys work, read how a crypto wallet works and custodial vs non-custodial wallets first.

What is DeFi used for?

The EBA and ESMA found that the main uses of DeFi are:

• Exchanging crypto-assets on decentralised exchanges, where smart contracts hold pools of tokens and set prices automatically.
• Lending and borrowing, where users deposit crypto as collateral to borrow other assets, or lend assets to earn interest from borrowers.
• Staking, locking crypto-assets to help run proof-of-stake blockchains in return for rewards.

Stablecoins are the common currency of much of this activity. Euro-denominated stablecoins, by contrast, remain negligible in DeFi markets, according to the same report. Our guide to what a stablecoin is covers how those tokens work.

How big is DeFi in the EU?

Smaller than the headlines suggest. The January 2025 EBA–ESMA report estimated:

• value locked in DeFi protocols at about 4% of total crypto-asset market capitalisation;
• 7.2 million DeFi users in the EU, of whom fewer than 15% seem to use DeFi regularly;
• DeFi lending and borrowing in the EU at roughly €1.8 billion, and DeFi staking at roughly €3.6 billion.

The same work found that EU banks have very limited engagement with DeFi, and that crypto lending or borrowing was being provided in 16 Member States and staking in 23, by both centralised firms and DeFi protocols.

DeFi vs a regulated crypto platform

Is DeFi regulated in the EU?

Partly, and the gap is important. MiCA regulates crypto-asset service providers: companies that provide custody, exchange, transfers and similar services. Services that are genuinely fully decentralised fall outside MiCA's scope. The joint consumer factsheet from the EBA, EIOPA and ESMA notes that not every unauthorised service is illegal, citing "fully decentralised" activity as an example of what is out of MiCA's scope.

What that means for you is spelled out in the same factsheet: if you use crypto-asset services that are not regulated under MiCA or other EU financial services law, "you may be exposed to significant risks and receive limited or no consumer protection."

MiCA asked the European Commission to report on developments including DeFi, and the EBA and ESMA fed their January 2025 report into that analysis. They said they would keep monitoring DeFi and did not make specific policy recommendations at that point.

One more rule worth knowing: under MiCA, issuers of e-money tokens such as USDC may not pay interest on them, and neither may crypto-asset service providers when providing services related to them. Yields on stablecoins advertised in DeFi come from somewhere else, usually lending to borrowers or protocol incentives, and carry the risks below.

What are the risks of DeFi?

The EBA and ESMA list several groups of risk. In plain terms:

Smart-contract and on-chain attacks. Bugs in contracts can be exploited, prices can be manipulated, and governance votes can be captured.

Off-chain attacks. Stolen private keys, phishing sites and fake front-ends. The regulators note recent attacks appear more successful when they exploit these off-chain weaknesses. Our guide to crypto scams covers common patterns.

Liquidation cascades. Borrowing against volatile collateral means a sharp price fall can trigger automatic sales, which push prices down further and trigger more sales across protocols.

Hidden costs and unclear terms. Users may get insufficient information on fees, yields, collateral changes and what the protocol can do with their assets. The regulators also highlight maximal extractable value (MEV), where block producers profit by reordering transactions at ordinary users' expense.

Staking risks. Prices can move during lock-up periods, liquid staking tokens can lose value, and penalties may not be clearly disclosed.

Concentration. The regulators found that 13 protocols account for 86% of the DeFi lending market.

Money-laundering exposure. Pseudonymous use makes DeFi attractive for laundering, which can lead to frozen funds or blocked transfers when assets later reach a regulated platform.

No safety net. No deposit guarantee, no investor compensation, often no company to complain to.

If you decide to try DeFi

Treat it as high risk and keep it small.

1. Only use money you can afford to lose entirely.
2. Learn self-custody first: back up your keys offline and never share a seed phrase.
3. Type addresses for interfaces yourself or use saved bookmarks. Do not follow links from messages or ads.
4. Read what you are signing. Wallet approvals can give a contract permission to move your tokens.
5. Prefer understanding over yield. A return you cannot explain is a risk you cannot price.
6. Keep records for tax. Swaps, rewards and loans can all have tax consequences; check with a tax adviser in your country.

Where Quppy fits

Quppy is not a DeFi product. Quppy Crypto is a custodial wallet and exchange: supported assets are held and administered by the applicable crypto-service provider, which in the EEA is Payhound Limited, a crypto-asset service provider authorised under MiCA by the Malta Financial Services Authority. Eligible users can hold, receive, send and exchange supported crypto-assets, and exchange them with EUR or GBP for supported pairs. Quppy's help centre does not describe lending, staking or yield features.

You can send supported assets from Quppy to a compatible external wallet, including one you use for DeFi. Before you do, read how to send crypto to an external wallet: the network must match, and blockchain transfers normally cannot be reversed.