Stack Bitcoin.
Automatically.
Deposit dollars, ETH or Bitcoin. Your principal stays put – the interest turns into Bitcoin automatically.
New to crypto? How to get your money onto Base →- ✓ Withdraw any time
- ✓ Fees on-chain
- ✓ No token of our own
How it works
Three steps. The hamster does the rest.
Deposit
Sign in with Face ID or your fingerprint. No seed phrase, no extension. Dollars, ETH or Bitcoin – buy directly by card.
Earn interest
Your principal is lent out on Aave, one of the largest DeFi protocols. No token of our own, no make-believe yield.
Collect Bitcoin
The interest turns into Bitcoin (cbBTC) automatically. Watch your cheek pouches fill up every day.
Want more Bitcoin?
Park your dollars with the hamster. Your money stays in dollars – no price risk on your principal. Only the interest turns into Bitcoin, every day. Stack sats without putting your savings on the line.
- ✓ Principal stays in dollars
- ✓ Withdraw any time
- ✓ Interest arrives as Bitcoin
- ✓ ≈ 4.7 % per year in Bitcoin
What's in it for me?
Do the math yourself – with today's interest rates.
Example values – live rates appear once the vaults are connected. What does it cost?
Crypto-Café Tax creates your tax report automatically – including DeFi vaults like Hamstr.
Pick your hamster
Every vault pays its yield in Bitcoin.
Dollar Hamster
Your dollars stay dollars. Only the interest becomes Bitcoin.
- Deposit
- USDC
- Yield in
- cbBTC
- Source
- Aave lending
- Yield p.a. (example)
- 5.2 %
No price risk on your principal. Smart contract risk at Aave and Hamstr.
ETH Hamster
Your ETH stays ETH. Only the interest becomes Bitcoin.
- Deposit
- ETH
- Yield in
- cbBTC
- Source
- Aave lending
- Yield p.a. (example)
- 1.4 %
ETH price risk remains. Smart contract risk at Aave and Hamstr.
Full Hamster
For believers: Bitcoin in, more Bitcoin out.
- Deposit
- cbBTC
- Yield in
- cbBTC
- Source
- Aave lending
- Yield p.a.
- –
Until then: park dollars – the interest turns into Bitcoin.
Cute, not naive
How we protect your money – and what you should know.
You stay in control
Non-custodial: your balance sits in the smart contract, not with us. You can withdraw any time – even while the vault is paused.
Fees capped in code
At most 20 % performance fee – fixed in the contract. Every change is announced 2 days ahead through a timelock.
A careful start
During the beta, deposits are capped per person and in total. An emergency multisig can pull everything out of the strategy.
Open and verifiable
Built on audited OpenZeppelin code. The source code is public. External audit status: pending.
Checked by us. Verifiable by you.
Before anything goes live, the contracts run through automated tests and a static security analysis. You can check every number here yourself.
- 73 / 73
- tests passed
- 1,536
- random scenarios per test run (fuzzing)
- 29
- tests against the real Base network with Aave, Uniswap and Chainlink
- 0
- critical findings in the Slither analysis
- 8 / 8
- contracts publicly verified (Basescan & Sourcify)
More than 20 full test runs during development, most recently on 26 Oct 2026. 64 medium-level hints were reviewed one by one; none of them is exploitable.
Read the full report ↗Slither is an automated tool and does not replace an audit. Trail of Bits has not reviewed Hamstr and is not affiliated with us. An external audit will follow before the limits go up.
Security status
Our contracts
- Dollar Hamster
- ETH Hamster
- Turbo Hamster
- Timelock (admin)
Behind the scenes (4)
- Dollar strategy (Aave)
- ETH strategy (Aave)
- Bitcoin swap
- Turbo swap
Built on
- Aave V3 ↗Lending – where the interest comes from
- Uniswap V3 ↗Swapping the interest into Bitcoin
- Chainlink ↗Market prices that protect the swap
- cbBTC (Coinbase) ↗Bitcoin on Base, backed 1:1 by Coinbase
- Base ↗The blockchain Hamstr runs on
Hamstr is an independent project. We use these projects' public protocols but have no partnership with them.
Questions
Where does the yield come from?+
From interest paid by people who borrow on Aave. Not from new deposits and not from a token of our own. The interest is swapped to Bitcoin on Uniswap – only at a price close to the Chainlink market price.
What does it cost?+
Depositing and withdrawing are free. We keep 10 % of the interest – only when you earn, never from your principal. The yield shown is already after this fee. The 20 % cap is fixed in the smart contract, and every change is announced 2 days ahead.
What is cbBTC?+
Bitcoin on the Base blockchain, backed 1:1 by real Bitcoin held by Coinbase. You can hold it, swap it or redeem it for regular Bitcoin at Coinbase any time.
Can I lose money?+
Yes. Smart contracts can have bugs, protocols like Aave can run into trouble, and prices move. Only deposit what you can afford to lose – especially during the beta.
Why a hamster?+
Because hamsters stash food in summer so they get through the winter. That's exactly what we do with Bitcoin.
Winter is coming. It always does.
Start stacking today – from $10.