Decentralised finance, or DeFi, is the part of crypto that replaces banks, brokers, and exchanges with code. Instead of asking a bank for a loan, you borrow from a pool of strangers through a smart contract. Instead of routing a transfer through Visa, you send stablecoins peer-to-peer. By Q3 2025, more than $237 billion was locked in DeFi protocols across Ethereum, Solana, and major Layer 2 networks.

This guide explains what DeFi is, how it works, what you can actually do with it, the benefits and risks involved, and how to get started without making the common beginner mistakes.

In this article

• What is decentralised finance?
• DeFi vs traditional finance
• How DeFi works
• The main parts of the DeFi ecosystem
• Benefits of DeFi
• Risks of DeFi
• How to get started with DeFi
• How Tothemoon fits into the DeFi landscape

What Is Decentralised Finance (DeFi)?

Decentralised finance (DeFi) is a system of financial services that runs on public blockchains instead of through banks and regulated intermediaries. Lending, borrowing, trading, saving, and insurance are all available, but they happen between users and smart contracts rather than through a central institution.

The defining feature is the absence of a gatekeeper. Anyone with an internet connection and a crypto wallet can use a DeFi protocol. There is no account application, no credit check, and no minimum balance. The protocol doesn't know who you are. It only sees a wallet address and a transaction.

DeFi is built almost entirely on Ethereum and chains compatible with it (Solana, BNB Chain, Polygon, Arbitrum, Optimism, Base). The reason is that smart contracts, the programmable code that runs DeFi, need a blockchain that can execute them. Bitcoin can hold value, but can't natively run the kind of logic DeFi requires.

DeFi vs Traditional Finance

The cleanest way to understand DeFi is to compare it with the centralised system most people already use.

• Custody. In a bank, the bank holds your money. In DeFi, your wallet holds your funds. You control the private keys.
• Access. A bank decides who can open an account. A DeFi protocol accepts any wallet that connects.
• Hours. Banks operate during business hours and rest days. DeFi runs continuously, every second of the year.
• Settlement. Wire transfers can take 1 to 5 business days across borders. A DeFi transaction settles in seconds to minutes.
• Transparency. Bank ledgers are private. DeFi balances and transactions are public, recorded on a chain that anyone can read.
• Intermediaries. A traditional loan goes through underwriters, branch managers, and compliance officers. A DeFi loan is a function call to a smart contract.
• Insurance. Bank deposits are usually insured up to a regulatory cap (FDIC in the US, MiCA-aligned schemes in the EU). DeFi has no equivalent. Losses from hacks or bugs are not reimbursed.

DeFi is faster, more accessible, and more transparent. It is also less forgiving. The user carries all the operational risk that a bank would normally carry.

How DeFi Works

DeFi rests on three building blocks: blockchains, smart contracts, and decentralised applications.

Public Blockchains

A blockchain is a shared ledger maintained by a network of computers. Every transaction is verified by validators and written to a block that becomes part of a permanent chain. Ethereum is the largest blockchain used in DeFi, followed by Solana, BNB Chain, and a wide set of Ethereum Layer 2 networks.

Smart Contracts

A smart contract is a small program deployed on a blockchain. Once it's live, it runs the moment its conditions are met. Nobody can stop it, change it, or override it without going through whatever upgrade process the contract defines. If the code says "swap 1 ETH for 2,500 USDC when the user calls this function," that's exactly what happens.

Decentralised Applications (dApps)

A dApp is a regular web interface plugged into a set of smart contracts. The interface looks like any modern fintech app. The difference is what happens when you click "approve." Instead of sending a request to a company server, the dApp asks your wallet to sign a transaction that talks directly to the contract on the chain.

A few of the largest dApps by usage:

• Uniswap. Decentralised exchange for swapping tokens.
• Aave. Lending and borrowing.
• Lido. Liquid staking for Ethereum.
• MakerDAO. Issues DAI, a crypto-collateralised stablecoin.
• Curve. Stablecoin swaps and liquidity pools.

The Main Parts of the DeFi Ecosystem

DeFi is not one product. It's a stack of services that compose with each other. Here are the categories that account for most of the activity.

Decentralised Exchanges (DEXs)

A DEX lets users swap tokens without an order book or a central operator. Most use a model called an Automated Market Maker (AMM), where prices are set by the ratio of tokens in a shared liquidity pool. Anyone can supply liquidity and earn a share of the trading fees. Uniswap, Curve, and PancakeSwap are the largest examples. https://blog.tothemoon.com/articles/market-takers-vs-market-makers 

Lending and Borrowing

DeFi lending protocols match lenders and borrowers without a credit officer. Lenders deposit assets into a pool and earn interest. Borrowers post collateral, usually more than 100% of the loan value, and draw funds against it. If the collateral drops below the required ratio, the smart contract liquidates it automatically.

Aave and Compound are the largest lending markets. Rates change every block based on supply and demand, which is why DeFi yields move much faster than bank deposit rates.

Stablecoins

Stablecoins are the dollars of DeFi. Most lending, trading, and yield activity is denominated in USDC, USDT, or DAI. Without stablecoins, every protocol would have to deal with the price swings of ETH or BTC. With them, users can earn yield, take loans, and settle trades in something that holds its value.

Yield Farming and Staking

Yield farming is the practice of moving funds between protocols to earn the highest available return. The yield comes from trading fees, lending interest, or token incentives that protocols pay to attract liquidity. Staking is more straightforward: lock a token into a validator (directly or through a liquid staking protocol like Lido) and earn a share of the network's block rewards.

Derivatives

DeFi derivatives include perpetual futures, options, and prediction markets, all running on smart contracts. Decentralised perp DEXs let traders go long or short with leverage without depositing to a centralised exchange.

Oracles

Many DeFi contracts need real-world data: the price of ETH, the result of an event, the value of a stock. Oracles, like Chainlink and Pyth, push that data on-chain so contracts can use it. Without reliable oracles, DeFi can't price collateral or settle derivatives, which is why oracle failures are one of the more common attack vectors.

Insurance and Risk Tools

DeFi insurance protocols like Nexus Mutual let users buy coverage against smart contract exploits, stablecoin de-pegs, and exchange failures. The cover pools are funded by capital providers who earn a yield in exchange for taking on the risk. It's not equivalent to FDIC, but it fills part of the gap.

Benefits of DeFi

DeFi exists because it solves real problems that traditional finance has not. The biggest ones:

Open Access

A wallet is the only requirement. There is no application, no KYC at the protocol layer, and no geographic restriction at the smart contract level. For users in countries with limited banking infrastructure, DeFi is often the most direct route to dollar-denominated savings, payments, and credit.

24/7 Markets

DeFi never closes. Lending rates update every block. A trade placed at 3 a.m. on Sunday settles the same way as one placed at 11 a.m. on Wednesday. For traders and treasurers operating across time zones, that continuous availability removes the weekend gap that traditional rails impose.

Composability

A DeFi protocol can plug directly into another DeFi protocol without permission. A lending market can use a DEX for liquidations. A yield aggregator can route funds through three protocols in a single transaction. This is why builders talk about DeFi as "money legos." Each piece is an open infrastructure that anyone else can build on top of.

Transparency

Every transaction, balance, and contract is visible on-chain. Auditors don't wait for a monthly statement. They query the blockchain directly. For institutional users, this turns reconciliation from a multi-day process into a real-time view.

Higher Yields for the Risk Taken

DeFi yields are often higher than bank deposit rates, especially for stablecoins. Some of that is the risk premium. Some of it is genuine efficiency from cutting out intermediaries. Either way, for users who understand the trade-offs, the return on capital can be materially better.

Risks of DeFi

The same properties that make DeFi powerful also make it risky. The biggest exposures:

Smart Contract Bugs

If the code has a flaw, the funds in the contract can be drained. The Wormhole bridge lost $325 million in 2022. The Ronin bridge lost $625 million the same year. The Euler Finance exploit cost $197 million in 2023. Audits help but don't eliminate this risk. In 2023 alone, attackers stole more than $1.1 billion from DeFi protocols.

Liquidation Risk

DeFi loans are over-collateralised. If the price of the collateral drops too fast, the contract liquidates the position automatically. Users can lose their collateral in minutes during a volatile market. There is no grace period and no call from a risk officer.

Stablecoin De-pegs

Most DeFi yield is denominated in stablecoins. If a stablecoin loses its peg, everything denominated in it loses value at the same time. USDC briefly dropped to $0.87 in March 2023 during the Silicon Valley Bank stress event. TerraUSD collapsed entirely in May 2022, wiping out roughly $40 billion in a week.

Oracle Manipulation

If an attacker can briefly distort the price feed a protocol uses, they can borrow against inflated collateral or trigger liquidations of others. Several DeFi exploits in the past three years have been oracle attacks rather than contract bugs.

Regulatory Uncertainty

Rules around DeFi are still being written. The EU's MiCA framework covers stablecoin issuers and centralised service providers, but leaves much of pure DeFi unaddressed. The US is moving toward clearer rules through the GENIUS Act and CLARITY Act. Tax treatment, KYC obligations for front-ends, and protocol-level compliance are all still in motion.

User Error

DeFi has no support line. A wrong address, a misclicked transaction, a phishing site, or a lost seed phrase can result in permanent loss. The largest single source of retail DeFi losses isn't hacks. It's user mistakes.

How to Get Started with DeFi

For users who want to try DeFi without taking on more risk than they can afford:

1. Start with a self-custody wallet. MetaMask, Rabby, and Phantom are the most common. Write down the seed phrase, store it offline, and never share it.
2. Fund it with a small amount. Buy ETH, USDC, or SOL on a regulated exchange and withdraw it to your wallet. Test the path before moving larger amounts.
3. Pick one protocol to learn. Don't farm five yield pools at once. Start with a major lending market (Aave) or a DEX (Uniswap) and understand how it works before adding complexity.
4. Use a Layer 2 for small transactions. Ethereum mainnet gas fees can make small DeFi trades uneconomical. Base, Arbitrum, and Optimism handle the same activity for cents.
5. Verify every transaction. Read what your wallet is about to sign. Most exploits at the user level are signed by the user.
6. Diversify. Don't put your full balance into one protocol or one stablecoin. DeFi rewards spread risk.

Conclusion

DeFi is finance rebuilt on public blockchains. It gives people open access, 24/7 markets, transparent settlement, and yields shaped more by real demand than by middlemen. But it also comes with serious risks: smart contract bugs, liquidations, stablecoin de-pegs, and fewer protections than traditional banking.