A perpetual future is a contract that tracks an asset's price with no settlement date. Because it never expires, there is no delivery to force convergence with spot, so the mechanism is a periodic payment called funding: when the contract trades above the underlying index, longs pay shorts; when it trades below, shorts pay longs. The payment makes the crowded side progressively expensive to hold, which is what pulls the contract back towards spot.
The design has made perpetuals the dominant instrument in crypto trading. They offer leverage, they require no roll, and they are available on more venues and in more pairs than any other product. Aggregate perpetual volume routinely exceeds spot volume by a large multiple, which has a consequence worth stating plainly: for much of the time, price discovery happens in the derivative and spot follows.
Funding is therefore a readable measure of positioning. Persistently positive funding means longs are paying to keep their exposure, which is a directional bet being expressed with borrowed money and a running cost. It is not a contrarian signal on its own — funding can stay positive through an entire trend, and the payment is small relative to the move — but extreme readings mark a market where one side is heavily crowded and paying for the privilege, and such markets unwind faster than they build.
Open interest is the companion figure and answers a different question: how much notional is outstanding. Price rising with open interest rising means new positions are opening into the move, which is participation. Price rising while open interest falls means the move is being driven by positions closing — a short squeeze rather than an accumulation. The distinction is not visible in the price chart at all, and it changes the interpretation of an identical candle.
The mechanism that makes all of this matter to holders who never touch a derivative is liquidation. Leveraged positions are closed automatically when margin is exhausted, and the closing is a market order. A cluster of positions with similar liquidation levels becomes, in effect, a queue of forced orders waiting at a price. When price reaches it, the liquidations execute into the spot and perpetual books, moving price further and triggering the next cluster. The resulting cascades are the sharp, deep wicks that appear on the chart and retrace within hours: they are the derivative market clearing itself through the spot book.
For a reader, three readings are worth following alongside price, and all three are published: funding rates across major venues, aggregate open interest, and liquidation volumes when a move happens. Together they distinguish a move driven by new capital from a move driven by existing positions being closed — which is the difference between a repricing and a squeeze, and it is invisible in the price alone.