Perpetual swaps, also known as perpetual futures, account for an estimated $40‑50 trillion in annual trading volume and are a major leveraged product used by professional traders, hedge funds and retail speculators to gain exposure to bitcoin and other cryptocurrencies without owning the underlying assets. The product evolved from traditional futures contracts, which expire at set dates, creating basis and rolling challenges in crypto markets. BitMEX, launched in 2014, shortened contract expirations to address these issues, before introducing perpetual swaps in 2016. These swaps have no expiry, allowing positions to remain open indefinitely. To align the swap price with the spot price, exchanges apply a funding rate every eight hours. Traders on the long side pay the opposite side when the swap trades above spot, and receive payments when it trades below. The rate increases with the size of the price deviation, creating a self‑correcting pressure. Market makers offset premiums by shorting the swap and buying the spot asset. Leverage is a core feature, with platforms offering positions many times the trader's margin. BitMEX previously offered up to 100× leverage. To protect exchanges from large losses, automated liquidation systems close positions once margin is depleted. The speed of these engines has become a competitive factor. Perpetual swaps now dominate price discovery in crypto, often leading spot price movements. Their structure has attracted regulatory interest, with U.S. regulators examining the use of perpetual swaps for traditional assets such as equities. The product, originally a solution to the limitations of crypto futures, is now one of the most widely traded financial instruments in the cryptocurrency market.