What Is Aave? How the Leading Lending Protocol Works

Aave is a decentralized lending protocol that lets users supply crypto assets to shared liquidity pools to earn interest, and borrow against posted collateral, with interest rates set algorithmically based on each pool's supply and demand rather than negotiated between individual lenders and borrowers.

Aave is one of the largest protocols in DeFi by total value locked, and it's frequently used as the reference example when explaining how on-chain lending works generally — see our broader DeFi lending explainer for the fundamentals this piece builds on.

How supplying assets works: aTokens

When you deposit an asset into an Aave pool, you receive a corresponding aToken (for example, aUSDC for supplied USDC) at a 1:1 ratio. This aToken isn't just a receipt — it's a live, interest-accruing representation of your deposit. Its balance increases in your wallet in real time as interest accrues, rather than requiring you to claim rewards separately, and it can generally be transferred or used elsewhere in DeFi (as collateral in some integrations, for instance) while still earning yield. Redeeming your original asset is as simple as returning the aToken to the protocol.

How borrowing works

To borrow, a user first supplies collateral, then borrows up to a percentage of that collateral's value — governed by a Loan-to-Value (LTV) ratio set individually for each asset based on its liquidity and volatility. More volatile or thinly-traded assets get lower LTVs (allowing less borrowing per dollar of collateral) as a risk-management measure; more liquid, lower-volatility assets like major stablecoins typically allow higher LTVs.

If the value of a borrower's collateral falls (or their borrowed amount grows via interest) enough that their position crosses a separate, more conservative liquidation threshold, the position becomes eligible for liquidation — a third party can repay part of the debt in exchange for a discounted slice of the collateral, protecting the pool's solvency. See our DeFi lending explainer and the liquidation glossary entry for how this mechanism generally works.

Variable vs. stable interest rates

Aave has historically offered borrowers a choice between two rate structures:

• Variable rate, which moves continuously based on a pool's current utilization — the ratio of borrowed funds to total supplied liquidity. As utilization rises toward a pool's target, rates increase to both compensate suppliers for scarcer available liquidity and discourage further borrowing; as utilization falls, rates ease back down.
• Stable rate (offered on some versions and markets, though its availability has changed over protocol versions), which locks in a rate largely insulated from short-term utilization swings, at the cost of typically being somewhat higher than the prevailing variable rate at the time of borrowing.

This utilization-driven model is the core mechanism that keeps Aave's pools functioning without a centralized rate-setter — rates are a direct, automatic response to real-time supply and demand for each asset.

Feature	Supplying	Borrowing
What you receive/provide	aTokens (interest-accruing)	Debt position against posted collateral
Rate driver	Pool utilization	Pool utilization (variable) or fixed at open (stable, where offered)
Risk	Smart contract risk, depeg risk on volatile collateral	Liquidation risk if collateral value falls

Risk management features

Aave uses several mechanisms to protect the protocol's overall solvency: a reserve factor that diverts a portion of interest paid by borrowers into a protocol-owned safety reserve; isolation mode, which restricts newer or riskier assets to being borrowed against in limited, contained ways rather than freely across the whole protocol; and a "safety module" where AAVE token stakers can back the protocol against shortfall events, in exchange for additional rewards and the risk of their stake being slashed if a shortfall actually occurs.

What actually determines your risk as a user

The clearest sources of risk on Aave are the same as most lending protocols: smart contract risk (bugs in the code, mitigated but never eliminated by audits and the protocol's long track record), oracle risk (if a price feed is manipulated or lags real market prices, it can trigger incorrect liquidations — see our DeFi oracles explainer), and market risk (a sudden, sharp price move in your collateral asset can trigger liquidation faster than you can react, especially if you're borrowing near the maximum LTV). Keeping a meaningful buffer below the maximum borrowable amount is the simplest way to manage this last risk.

How Aave compares to alternatives

Aave isn't the only lending protocol, and its specific interest rate model and risk parameters are worth comparing directly against alternatives like Compound — see our Aave vs. Compound comparison for a side-by-side look, and our Morpho explainer for how newer protocols have built optimization layers on top of pools like Aave's.

Bottom line

Aave lets you earn interest on supplied assets and borrow against collateral through algorithmic, utilization-driven interest rates rather than negotiated terms — but every position carries smart contract, oracle, and liquidation risk that scales with how close to the maximum LTV you choose to borrow. Check current yield rates and a specific asset's LTV and liquidation threshold directly on the protocol before opening any leveraged position.