The two-sentence version
Yield farming = lending or providing liquidity in DeFi protocols, in exchange for rewards. Think of it as putting your savings to work in code-mediated investments instead of letting them sit in a bank account at 0.01%.
How it actually works
There are roughly four ways to earn yield in DeFi:
1. Lending
You deposit a token. Borrowers pay interest to use it. You earn a slice of that interest. Simple and well-understood — Aave and Compound pioneered this model.
2. Liquidity providing (LP)
You put two tokens into a "pool" that lets others trade between them. Every trade pays a small fee, and that fee is shared with you (the LP). PancakeSwap and Uniswap work this way.
3. Staking
You lock your tokens to help secure a blockchain (Proof of Stake networks). The network pays you rewards. Examples: ETH staking on Ethereum, BNB staking on BNB Chain.
4. Yield aggregators
A smart contract automatically moves your funds between the highest-yielding strategies, harvesting and re-depositing rewards. Yearn Finance pioneered this.
What does APY actually mean?
APY = Annual Percentage Yield. It tells you how much you'd earn in a year if the current rate held constant.
Be skeptical of huge APYs:
- 5-15% on stablecoins from blue-chip lending = sustainable
- 50%+ requires a real revenue source (high trading volume, scarce liquidity, etc.) — possible but verify the source
- 1000%+ on a brand-new token = ponzi-shaped, almost always
The risks nobody mentions
- Impermanent loss — for two-token LP positions, you can lose value vs just holding the tokens. Doesn't apply to stablecoin-only pools.
- Smart contract risk — the code can be exploited. Always check audits and renouncement status.
- APY decay — high yields attract competitors. The 50% APY today might be 10% in 6 months.
- Token volatility — if you're farming a volatile token's price drop can wipe out your earnings.
How to evaluate any yield source
Three questions, every time:
- Where does the yield actually come from? Real fees? Token inflation? New deposits? (The last one is a red flag.)
- Is the smart contract verified and renounced? Verify on a block explorer.
- What happens if no new users join tomorrow? If the yield depends on growth, it's unsustainable.