PlainCoin
Chapter 4 DeFi basics Medium risk

How DeFi lending and borrowing work

How lending pools supply interest, why people borrow against crypto collateral, and what triggers liquidation.

The short version
  • Lending: deposit into a smart-contract pool, earn variable interest, get receipt tokens that accrue value.
  • Borrowing: post crypto as collateral, receive stablecoins — but fall below the ratio and the protocol auto-liquidates you.
  • Rates move with market demand; chaotic markets paying more is a warning sign, not a selling point.
  • Three risks to know: smart contract bugs, governance changes, oracle price-feed failures during crashes.

DeFi lending protocols let users deposit assets into smart-contract pools to earn interest, or borrow against crypto collateral without a traditional credit check.

01

Lending

Deposit stablecoins or major crypto into a protocol (e.g. Aave, Compound). Borrowers draw from the pool and pay variable interest. You receive receipt tokens representing your share, which accrue value as interest flows in.

Interest rates fluctuate with supply and demand. Higher rates during volatile markets often signal elevated borrower desperation — not necessarily a safe opportunity.

02

Borrowing

Common use case: hold ether long-term, deposit it as collateral, borrow stablecoins for liquidity without selling (avoiding taxes or maintaining exposure).

Loans are overcollateralized — deposit $150 of ETH to borrow ~$100 of USDC. If collateral value falls below the required ratio, the protocol liquidates automatically: sells your collateral, often with a penalty.

03

Risk summary

RiskWhat it means
Smart contractCode holds funds; audits reduce but don’t eliminate bugs
GovernanceProtocol parameters can change via token-holder votes
OraclePrice feed failures during crashes can trigger unfair liquidations
⚑ One honest flag

Simulate a 30% price drop on your collateral before borrowing. If liquidation at that level would cause significant loss, reduce position size or avoid borrowing entirely.

If this cleared something up, you can buy me a coffee.

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