Use Compound v3 to Lend
How to deposit and borrow on Compound v3: per-market design, supply-only assets, and COMP rewards.
What you'll need (prerequisites)
- Self-custodial wallet (MetaMask, Rabby, etc.)
- ETH or native gas token
- Tokens to lend with
- Familiarity with transaction approvals
Recommended for this tutorial
Tools and accounts referenced in the steps below:
Step-by-step
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Step 1: Connect a self-custodial wallet
Open Compound's official site (verify the URL — phishing fakes are common). Click "Connect Wallet" and choose your wallet (MetaMask, Rabby, WalletConnect, hardware). Approve the signature request — this does not move funds.
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Step 2: Select the correct network
Confirm your wallet is on the network Compound expects (Ethereum mainnet, Arbitrum, Base, Polygon etc.). Wrong-network connections are the #1 source of UX confusion.
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Step 3: Acquire the input tokens
Most Compound actions require both a token and ETH (or the chain's native token) for gas. Hold a small buffer (~$10-20) for transaction fees.
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Step 4: Approve token spend
For ERC-20 tokens, the first interaction requires an "approve" transaction granting Compound permission to move that token. Approve the exact amount (not unlimited) when possible to limit downside if Compound is ever exploited.
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Step 5: Execute the lend transaction
Enter the amount and review the transaction details. Click confirm and approve in your wallet. Wait for on-chain confirmation.
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Step 6: Verify on-chain
Open the transaction on Etherscan / Arbiscan / Basescan. Confirm the balance change matches expectations. Save the transaction hash for tax records.
Common errors and fixes
- Transaction reverted. Most reverts are slippage exceeded, allowance not set, or insufficient gas. Increase slippage marginally and retry, or check Tenderly for the revert reason.
- Stuck pending transaction. Speed up with a higher gas price (replace-by-fee) or cancel by sending a 0-value tx to yourself with the same nonce and higher gas.
- Approved a malicious contract. Immediately revoke at revoke.cash. Move remaining tokens to a fresh wallet if you suspect ongoing compromise.
- Wrong network. Switch chains in your wallet. If funds were sent cross-chain to a contract that doesn't exist on the destination, contact the bridge support.
- Slippage too high. For thin-liquidity tokens, split the swap into smaller chunks or route via an aggregator (1inch, CoW Swap, Matcha) which finds better paths.
FAQ
Is Compound safe?
Compound is one of the most widely used and audited protocols in DeFi. As with any smart-contract platform, residual risk includes: smart-contract bugs, oracle failure, governance attack, and economic exploits. Diversify across protocols and never deposit more than you can afford to lose.
What are the fees for Compound?
Protocol-level fees vary by action and chain. Network gas adds another $0.50-50 depending on chain congestion (much cheaper on L2s than Ethereum mainnet). Always preview fees before confirming.
Can I undo the transaction?
On-chain transactions are irreversible. Always test with small amounts first, double-check addresses and amounts, and use simulation tools (Tenderly, Pocket Universe) to preview the outcome.
Does Compound have an audit?
Yes — Compound has been audited by tier-1 firms (typically Trail of Bits, OpenZeppelin, ChainSecurity, Zellic, Spearbit). Audit reports are linked from the official docs. Audits reduce but never eliminate risk.
What is impermanent loss / liquidation risk?
For LP positions, impermanent loss is the difference between holding the LP vs holding the underlying tokens — it grows with price divergence. For lending positions, liquidation risk grows as collateral price falls; maintain a health factor well above 1.