DeFi 101: 탈중앙화 금융

Source: Dev.to

Welcome back to the 60‑Day Web3 Journey. You’ve just deployed a smart contract on Ethereum and saw how code can live on a blockchain. Now comes the real question: what are people actually doing with these contracts? The answer is that they’re building an entirely new financial system—DeFi (Decentralized Finance)—where smart contracts become the backbone of trading, lending, borrowing, and earning without banks.

What Is DeFi, Really?

DeFi is finance without a middleman. Instead of a bank holding your money, a smart contract does. Instead of a broker matching your trade, an algorithm does. Instead of a lender deciding if you qualify, code does.

Core idea: take every financial service you know—trading, lending, borrowing, investing—and rebuild it as code that anyone can use, anytime, from anywhere.

Traditional Finance vs. DeFi

How DeFi Actually Works

1. Decentralized Exchanges (DEXes) – Swap Tokens Instantly

A DEX is like a vending machine for crypto: you put in one token, you get another token out—no human operator, no waiting, no fees to a company.

• Example: Uniswap – as of December 2025, over $5.7 B locked in it.
• How it works:
  1. A liquidity provider deposits two tokens into a smart contract (e.g., $1 M ETH + $1 M USDC).
  2. The contract creates a pool of both tokens.
  3. You send 10 ETH to the contract to swap for USDC.
  4. The contract automatically calculates the price and sends you USDC.
  5. The liquidity provider earns a tiny percentage of every swap.

Uniswap v4 (launched mid‑2025) hit $1 B TVL in just 177 days and processed over $1 T in annual trading volume.

2. Lending Protocols – Earn Interest, Take Loans

Deposit crypto and earn interest without a bank. The leading protocol is Aave.

• Aave stats (mid‑2025): > $60 B in deposits, $29 B in outstanding loans, ~60 % of the DeFi lending market.

• Deposit flow:

  1. Deposit 100 USDC.
  2. Aave lends it out; borrowers pay interest (e.g., 5 % APY).
  3. You earn that interest (minus a small protocol cut).
  4. Withdraw anytime with accrued interest.

• Borrow flow:

  1. Deposit collateral (e.g., 1 ETH ≈ $2,500).
  2. Borrow up to 70 % of collateral value (e.g., $1,750 USDC).
  3. Pay interest on the loan.
  4. Repay + interest to retrieve collateral.

In August 2025, Aave’s TVL grew by 55 %; Q2 2025 fees reached $122 M.

3. Yield Farming – Stake Tokens, Earn Rewards

Yield farming lets you lock tokens in a protocol and earn rewards, often in newly minted tokens.

• Example: Deposit ETH and USDC into Uniswap’s liquidity pool.
• Rewards: Share of trading fees plus UNI tokens as a bonus.

Protocols use these incentives to attract liquidity and borrowing activity.

Why Does This Matter? (2025 Context)

Scale

• 14.2 M wallets have used DeFi protocols (mid‑2025) – CoinLaw DeFi Statistics 2025.
• Total DeFi TVL: $123.6 B, a 41 % YoY increase – NASSCOM Blockchain Community.
• Weekly transaction volume: $48 B – TradeSanta DeFi Trends 2025.
• Avg. DeFi user: 11.6 transactions/month – CoinLaw DeFi Statistics 2025.

Adoption

• Gen Z (18‑25) accounts for 38 % of first‑time DeFi wallet users (2025) – Brave New Coin.
• Mobile DeFi wallet usage up 45 %, now 58 % of all users – CoinLaw DeFi Statistics 2025.
• Google Trends DeFi interest: 92/100, highest in 18 months – CoinLaw DeFi Statistics 2025.
• Active DeFi users: 20 M unique wallets globally, a 2,000 % increase since 2021 – CoinLaw Crypto Demographics 2025.

Institutional Money

• Real‑world asset (RWA) lending surged to $1.9 B for commodity‑backed tokens – CoinGecko RWA 2025 Report.
• Tokenized private credit exceeds $12 B TVL (Mar 2025), > 50 % of the RWA market – Antier Solutions.
• Aave founder Stani Kulechov’s Horizon platform (RWA‑backed lending) surpassed $500 M in deposits – Chainlink Today.

DeFi is no longer a niche experiment; it’s becoming core financial infrastructure.