Wallet
Software or hardware that stores your private keys and allows you to interact with blockchains. To use DeFi lending, you need a non-custodial wallet like MetaMask, Ledger, or Coinbase Wallet.
Your wallet is your identity on a blockchain. It doesn't store coins the way a leather wallet stores cash — it stores the private key that proves you own whatever is recorded on-chain. Lose the key, lose the assets. Full stop.
For crypto lending, the wallet is the front door. Every time you deposit collateral on Aave, borrow against your ETH on a CeFi platform, or approve a smart contract to move your funds, that action is signed by your wallet. No wallet, no access.
How It Works
A wallet generates two things: a public address (like a bank account number — share it freely) and a private key (like a PIN that controls everything — share it with no one). Your public address is where funds arrive. Your private key is what authorizes them to move.
Non-custodial wallets — MetaMask, Ledger, Coinbase Wallet — mean you hold the private key yourself. Custodial wallets, like the one inside a centralized exchange, mean the platform holds the key on your behalf. That distinction is everything in lending.
When you connect a non-custodial wallet to a DeFi protocol like Compound, you're not logging in — you're authorizing a smart contract to interact with your address. The protocol never takes custody. Your collateral moves on-chain, governed by code, not a company.
Why It Matters
In DeFi lending, your wallet is also your credit file, your loan application, and your closing table — all at once. The protocol reads your on-chain balance, calculates your loan-to-value ratio, and executes the loan, all through a single wallet connection. There's no underwriter in the middle.
What is Smart Contract?
Self-executing code on a blockchain that automatically enforces the terms of an agreement. All DeFi lending protocols operate through smart contracts that handle deposits, loans, interest, and liquidations.
Full glossary entryBill's Take
In 25 years of mortgage lending, the borrower's identity was always verified by a third party — a title company, a notary, a bank. In DeFi, the wallet IS the identity. There's no fallback if something goes wrong. That's not a criticism — it's a structural fact you need to understand before you put real money in.
What to Watch
Custodial versus non-custodial is the single most important wallet distinction for lenders and borrowers. If your funds sit in an exchange wallet, the exchange controls the keys — and can freeze withdrawals, restrict access, or become insolvent. Celsius, Voyager, and BlockFi all held customer keys. All three froze withdrawals in 2022.
Seed phrase security is the other half of this. Your 12- or 24-word recovery phrase regenerates your private key on any device. Anyone who has it owns your wallet — no password, no 2FA, no customer support call can stop them. Store it offline, physically, in more than one location.
Custody Risk
Not your keys, not your coins. It's a cliché because it's true. If you're using a non-custodial wallet for DeFi lending, the security of your entire position — collateral, loans, yield — depends on one piece of information you wrote down on paper. Treat it like a bearer bond.
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