How does it work?
You are able to fund your perpetual positions using USDT. When depositing USDT, your USDT is automatically converted to USDC using Curve liquidity pools. When withdrawing funds as USDT, the USDC in your perpetual account is then converted back to USDT on Curve. Curve is a stable-coin swapping protocol on Ethereum.
Can I set a custom slippage?
The expected conversion amounts are shown as you type in the input box, but you can also set custom slippage in the deposit and withdrawal modals.
Are there any fees for this conversion?
dYdX does not take any fees on this conversion. A small fee is taken by the Curve contracts itself (currently 4 bps). You will also have to pay the Ethereum gas fees to execute these deposits and withdrawals.
I don't trust USDT, is there any additional risk?
If you don't want to use USDT, there is no additional risk or exposure to USDT. All funds held in the BTC-USD perpetual are still held as USDC.
Can I deposit USDT for margin-trading?
No. One roundabout way to do this is to convert it into the perpetual and then withdraw and deposit the USDC into your margin account.