What the screener actually catches
Twelve kinds of signal, grouped by the feed they read. For each: what happened on the exchange, which stream shows it, and how to read it. None of them is an indicator — everything below is an event in the trade tape, in the order book, or on derivatives.
From the trade tape
The tape is the stream of completed trades: price, size, side, time. Four of the five signals here read it directly; the fifth reads the shape a move leaves behind over a window.
Momentum — a price spike
A move that clears a change threshold inside its own timeframe. The only scanner that also works in the grid, meaning you can sort the whole board by it rather than only receive it in the feed.
Large trade
A single order big enough to matter. The threshold is set in money and set per exchange: a print that moves price on a thin market goes unnoticed on Binance.
Book sweep
Aggression that took several levels off one side in a row. It differs from a large print in what matters — not the size of one order but how many levels went, which is the price somebody agreed to pay to get in immediately.
Algo activity — the bot detector
Repeated trades of one size at an even cadence: one participant working an order, not a crowd. It is the earliest sign that somebody is building or unloading a position in pieces.
Whipsaw
Out and back inside one window: the shape that takes out stops on both sides. Measured by its swing rather than by its net change, so a coin that went and came back does not look calm.
From the L2 book
The book is the trades that have not happened yet: intentions visible before they become price. Not every exchange streams it, and the app lists the ones it is reading right on the walls board.
Liquidity wall
Resting size in the book near price, large enough to hold or to be broken. Distance from the mid counts as much as size: the same wall three percent away and three tenths of a percent away are two different events.
Absorption
Price is being hit and does not move: somebody is taking it all quietly. The signal is precisely the mismatch between aggression and result — heavy one-sided volume and almost no displacement.
Spoof
A wall that appeared and vanished without ever being traded. A separate kind rather than a sub-case of a wall, because it reads the opposite way: a pulled order is usually a pulled intention.
From derivatives
Perpetual futures carry three streams spot does not have: forced closes, the funding rate, and open interest.
Liquidation
A position closed by the exchange by force, and cascades of them. A long liquidation reaches the tape as a sell and a short liquidation as a buy; every string in the product is written in positions rather than orders, because that is how a trader reads it.
Funding
A rate running hot into settlement. Exchanges settle differently — usually every eight hours, sometimes every four or every hour — so the product normalises a rate to eight hours when two venues need comparing.
Open-interest shift
Positions opened or closed, read against the price move to say which. Measured in position size rather than notional, so a coin that merely got more expensive produces nothing — which is exactly how it was broken while the metric differenced dollars.
Across venues
Divergence
The same coin priced materially differently in different places. Spot and perpetuals are compared separately: a perp trading above spot is funding doing its job, not a price dislocation.
What all twelve have in common
Every signal carries the venue, the side, the size and the event time — and a judgement on execution: machine or person. The tape can be kept to bots only or people only, which is the first filter anyone reaches for when the book gets noisy.
Thresholds are set per scanner and per exchange. A move big enough to deserve interrupting you is tagged VIP: it changes the signal’s severity, its place in the list, and whether it is spoken out loud.