Perpetual swaps, also known as perpetual futures or perpetual contracts, are a type of futures contract that has no expiration date. This means that the contract remains active indefinitely, with no settlement date or expiration date, unless the trader chooses to close the position or the exchange terminates the contract.

Perpetual swaps are similar to traditional futures contracts in that they:

1. Obligate the buyer and seller to buy and sell an underlying asset at a predetermined price.

2. Allow traders to speculate on price movements or hedge against potential losses.

3. Offer leverage, enabling traders to control large positions with relatively small capital.

However, perpetual swaps differ from traditional futures contracts in that they:

1. Have no expiration date, allowing traders to hold positions indefinitely.

2. Typically have a funding rate or interest rate component, which is exchanged between the buyer and seller periodically (e.g., daily or weekly).

3. May have a variable price or rate, which is adjusted based on market conditions or the underlying asset's price movement.

Perpetual swaps are popular in cryptocurrency markets, particularly for Bitcoin and other digital assets, as they offer traders the ability to speculate on price movements without the need to roll over positions or worry about expiration dates. However, it's essential to understand the unique characteristics and risks associated with perpetual swaps, including the funding rate, leverage, and market volatility.