Hyperliquid API wallets: what an agent key can and cannot do
An API wallet is how you let software trade your Hyperliquid account without giving it your wallet. Hyperliquid also calls it an agent; Helmsman calls it a trading key.
In private testing: the trading engine is not live yet. The console you can open today shows sample data and nothing is traded. These pages describe how Helmsman is built to work.
What it is
A separate key pair that your main wallet approves with one off-chain signature. No gas is spent. From then on, orders signed by that key are accepted as yours.
What it can and cannot do
It can
Place and cancel orders, change leverage and margin mode, move margin into an isolated position.
It cannot
Withdraw, transfer, approve another API wallet, or approve a builder fee. Those need your main wallet.
How long it lasts and how many you get
An approval can be given an expiry of up to 180 days. After that every action fails until you approve a new one.
An account has room for one unnamed API wallet and up to three named ones. If other apps already use yours, remove one at app.hyperliquid.xyz → More → API before approving another.
Revoking one
Remove it on the same API page. The app that held it is locked out immediately. A well-behaved app generates a fresh key for every approval and never reuses an old address.
What to watch for
- An API wallet cannot take funds out, but it can lose them by trading. Permissions are all-or-nothing: there is no “cancel only” key.
- No legitimate app needs your main wallet’s private key or seed phrase to set one up.
- Check the domain in the signature request matches the site you are on.