Compound is a DeFi lending protocol that allows users to earn interest on their cryptocurrency by depositing it into one of the multiple liquidity pools supported by the platform.

When users deposit tokens into the Compound pool, they receive CTokens in return. These Ctokens represent an individual's stake in the pool and can be used at any time to redeem the underlying cryptocurrency originally deposited in the pool. For example, by putting ETH in the pool, you will receive cETH in return. Over time, the exchange rate of these Ctokens against the underlying asset rises, meaning you can use them to redeem more of the underlying asset than you originally put in, and that's how the interest is distributed.

On the other hand, borrowers can obtain secured loans from any Compound pool by depositing collateral. Maximum loan-to-value (LTV) ratios vary by mortgage asset, but currently range from 50 to 75 per cent. Interest rates paid vary for borrowed assets, and borrowers may face automatic liquidation if their collateral falls below certain maintenance thresholds.

Since main Compound launched in September 2018, the platform's popularity has skyrocketed, with a total lock-in value of more than $10 billion.