DeFi lending explained: how it works and how to use it safely

DeFi lending is what banking looks like when you replace the bank with a smart contract. Lenders deposit crypto into a pool; borrowers pledge other crypto as collateral and take loans from that pool; interest flows back to lenders automatically. The whole arrangement settles in seconds, no application, no underwriter, no manager. It also means the protocol (not a human) decides when to liquidate, freeze, or repay.

How does DeFi lending work?

Most DeFi lending sits in one of two patterns:

Money-market pools (Aave, Compound, Morpho)

1. Lenders deposit an asset (USDC, ETH, etc.) into a shared pool. They receive a yield-bearing receipt token (aUSDC, cUSDC, etc.).
2. Borrowers deposit collateral into the same protocol (often a different asset than what they want to borrow).
3. Borrowers borrow against the pool, up to a fraction of their collateral’s value (the loan-to-value).
4. Interest accrues continuously. The rate floats with utilization.
5. Liquidation engine watches every borrow. If a borrower’s collateral drops below the liquidation threshold, any liquidator can call a function to sell the collateral and repay the loan, taking a small bounty.

Peer-to-peer lending (Teller Protocol, NFTfi, others)

Loans are matched one-to-one between a specific lender and a specific borrower at a fixed rate and a fixed term. No pool, no utilization curve, just an order book. Best for fixed-rate certainty and for collateral that pools don’t list.

DeFi pool vs CeFi lender vs marketplace loan

“Crypto lending” covers three structurally different products, and the differences matter more than the rates:

The marketplace column is how the unsecured path through Teller works: partner lenders underwrite you on income, credit tier, and on-chain signals, then disburse cash directly. What that underwriting actually looks at is covered in the unsecured crypto loan requirements guide, and for a head-to-head between a money market and a marketplace, see Teller vs Aave.

Why do rates change in DeFi lending?

Every pool has an interest-rate model, usually a curve that’s roughly linear up to a target utilization (say 80%), then steep above it. The model has three jobs:

• Reward lenders proportional to demand. More borrowing → higher rates.
• Discourage 100% utilization. If a pool runs out of supply, lenders can’t withdraw. The kink in the curve makes the last 20% of utilization expensive.
• Self-correct. High rates pull in new lenders and push borrowers to repay; low rates do the opposite.

What are the risks for lenders?

• Smart-contract risk. A bug, exploit, or upgrade gone wrong can drain a pool. Audits help; insurance products (Nexus Mutual, Sherlock) exist but are imperfect.
• Oracle risk. Lending pools price collateral using on-chain oracles. A manipulated or stale oracle can make undercollateralized loans look healthy until the pool takes a loss.
• Liquidity risk. If utilization spikes to ~100%, you may not be able to withdraw immediately. Funds aren’t lost; they’re just locked until borrowers repay.
• Governance risk. Protocols can change parameters (rate curves, supported assets, liquidation thresholds) through token-holder votes. Pay attention.

What are the risks for borrowers?

• Liquidation. The defining risk. Your collateral can be sold without warning if its price drops below the threshold.
• Rate spikes. A variable-rate loan can become uneconomic if utilization in the pool jumps.
• The other risks lenders face (smart-contract, oracle, governance) apply to borrowers’ collateral too.

Our dedicated crypto-backed loans guide walks through the borrower-side mechanics in depth.

What are the alternatives to centralized crypto lenders?

If you want to lend or borrow without handing assets to a company, you have three real alternatives: non-custodial DeFi pools (your assets sit in a contract you can verify, not on a company’s balance sheet), peer-to-peer protocols with fixed terms, and, for borrowing specifically, a regulated marketplace loan paid out as cash to your bank account with no crypto pledged at all.

The bear-market record is the honest filter here. The platforms that failed in past cycles shared a structure, not a logo: they took custody of customer assets, lent them out opaquely, and promised yields that their books couldn’t support. The structures that kept operating through the same stress shared the opposite traits:

• Overcollateralization enforced by code. Pools that require more collateral than debt don’t depend on any borrower’s promise to stay solvent.
• Transparency you can verify. On-chain positions, open-source contracts, and proof-of-reserves beat quarterly assurances from a company treasury.
• Non-custodial design. If the operator disappearing can’t take your deposit with it, an operator failure is an inconvenience rather than a loss.

So instead of asking “which brand is safe,” ask whether the structure has those three properties. How US rules treat each of these models is changing fast; the US crypto lending regulation guide maps the landscape. And whatever you pick, screen it against the red flags in our loan-scam guide; the collapse-prone and the fraudulent tend to advertise the same way.

How do I get started with DeFi lending?

1. Get a non-custodial wallet. See our wallet guide.
2. Fund it with stablecoins on a Layer-2. Base, Arbitrum, and Optimism keep gas low.
3. Pick a pool or an offer. Teller surfaces live lending opportunities and borrow offers from across protocols on the home tab.
4. Start small. Deposit or borrow a fraction of your stack to learn the UX. Scale once you’ve been through one full cycle.
5. Track your positions. Health factor / LTV / utilization are the numbers that matter; monitor them.

The short version

DeFi lending is open, fast, and global. The yield comes from real on-chain demand, not from a bank’s spread. The price is that nothing is forgiving. If the contract triggers a liquidation, there’s no one to call. Used carefully it’s one of the best tools in crypto; used recklessly it’s a fast way to lose a position.

Where to start

If you want to lend, start small in an established non-custodial pool and track your position through one full cycle before scaling. If you want to borrow and would rather not pledge collateral or risk liquidation at all, see whether you pre-qualify for a marketplace loan: a soft check of about four minutes, no hard credit pull, and any approved loan is paid out by a partner lender as USD to your own bank account.