Cryptografy

In traditional finance, you deposit money at a bank, the bank lends it out, and you get a fraction of the interest. In DeFi, you cut out the bank entirely. A smart contract handles everything - matching lenders and borrowers, setting interest rates, and enforcing repayment. No humans in the loop.

Sounds futuristic? It has been running in production since 2020 with billions of dollars flowing through it every day.

How It Works, Step by Step

1. Lenders deposit crypto. You deposit ETH, stablecoins, or other supported tokens into a lending protocol. Your funds go into a shared pool.

2. Borrowers take loans. Someone who wants to borrow puts up collateral (usually 150% or more of what they want to borrow) and draws a loan from that pool.

3. Interest accrues automatically. The smart contract calculates interest rates based on supply and demand. More demand to borrow means higher rates for lenders.

4. Repayment or liquidation. If the borrower repays, they get their collateral back. If their collateral drops below the minimum ratio, anyone can liquidate the position - the protocol sells the collateral to repay lenders.

Why Would Anyone Borrow If They Need More Collateral Than They Borrow?

This is the question everyone asks first, and it is a good one. The answer comes down to a few scenarios:

Tax efficiency - Borrowing against your ETH is not a taxable event. Selling it is.
Leverage - Borrow stablecoins, buy more ETH, deposit that ETH as more collateral, borrow more. Risky but common.
Liquidity without selling - You believe ETH will go up but need cash now. Borrow against it instead of selling.
Short selling - Borrow an asset, sell it, buy it back cheaper later. Profit on the price drop.

The Major Protocols

Top DeFi Lending Protocols

Protocol	TVL	Chains	Key Feature
Aave	$10B+	Ethereum, Arbitrum, Polygon, others	Flash loans, multi-chain
Compound	$2B+	Ethereum, Base	Simple, battle-tested
MakerDAO (Sky)	$8B+	Ethereum	Issues DAI stablecoin against collateral
Morpho	$3B+	Ethereum, Base	Peer-to-peer matching layer
Spark	$4B+	Ethereum	MakerDAO's lending front-end

Aave's governance token AAVE$115.97AAVE$115.9724h+0.01%7d-6.80%30d-10.70%1y-46.26%MCap: N/AVol: N/Avia Statility is the largest pure lending protocol by market cap.

Typical Interest Rates

Rates fluctuate constantly based on utilization (how much of the pool is being borrowed). Here is what you might see on a typical day:

Sample DeFi Lending Rates

Asset	Supply APY	Borrow APY	Typical Utilization
USDC	3-8%	5-12%	70-85%
ETH	1-3%	3-6%	50-70%
WBTC	0.5-2%	2-5%	30-50%
DAI	4-9%	6-13%	75-90%

Compare this to your bank savings account (probably 0.01-4%) and you can see the appeal. But higher returns come with higher risk.

The Risks You Need to Know

Smart contract risk. If there is a bug in the code, funds can be drained. This has happened. Aave★★★★★4.4Aaveservice★★★★★4.4/51 AI reviewAave is a decentralized finance (DeFi) protocol that allows users to lend and borrow cryptocurrencies without interme...via Rexiew Aave and Compound★★★★☆4.1Compoundservice★★★★☆4.1/51 AI reviewCompound is a decentralized finance (DeFi) protocol on the Ethereum blockchain that allows users to lend and borrow c...via Rexiew Compound have been audited extensively and have operated safely for years, but "audited" does not mean "risk-free."

Liquidation risk (for borrowers). If your collateral drops too fast, you can lose it. During the May 2021 crash, over $600 million was liquidated across DeFi in a single day.

Oracle risk. Lending protocols rely on price feeds (oracles) to determine collateral values. If the oracle reports a wrong price, incorrect liquidations can happen.

Regulatory risk. Governments are still figuring out how to classify and regulate DeFi lending. Rules could change.

DeFi lending is not a savings account. It is a financial tool with real risk. The returns reflect that risk - if they seem too good to be true, look harder at what could go wrong.