A large player shows up in the order book before their move shows up on the chart: first someone places the size, then the price follows. HookScreener connects directly to the trade and order-book streams of 10 crypto exchanges and watches them around the clock for four footprints of large capital — liquidity walls, trading robots, liquidity sweeps and price pushing. From the event on the exchange to the alert in your terminal takes 3–5 seconds. Here is exactly how that works.
The path of a signal
Four steps every market event passes through. Seconds separate the first from the last.
One persistent WebSocket connection per stream: the trade feed and the order book. We do not poll a public REST API on a schedule — the exchange pushes us every change the moment it happens. That is where seconds instead of minutes come from.
For every pair we keep a full copy of the book and update it with each delta the exchange sends. That means we see more than the current snapshot: we see a level's history — when a wall appeared, whether it grew, and whether it was eaten or pulled.
Every trade and every book update passes through four independent detectors. They do not look for "big numbers" — they look for specific structures: resting limit size, the rhythm of an algorithm, a sweep with a return, a wall being replaced higher.
Most of what we find never reaches you — and that is the system's main job. Market-maker grids, repeats of the same event, and orders sitting hundreds of percent away from price are removed by filters. The rest goes to the terminal in real time, with no manual moderation.
Why it's fast
Most screeners work by polling: every 5, 30 or 60 seconds they hit an exchange's REST API and compare snapshots — some state their refresh interval in minutes outright. Anything that starts and finishes inside that interval does not exist for that screener. And a liquidity sweep lives for seconds: it fits entirely inside the gap between two polls.
HookScreener holds persistent WebSocket connections to all 10 exchanges at once. The exchange sends each trade and each book change as it happens. Our detectors receive the same stream the exchange's own trading terminal does — so an event that lasted a second is still one we see in full.
3–5 secfrom the event on the exchange to the alert in your terminal
The detectors
Four detectors run in parallel and independently. Below is the signal each one decides on. What each signal means for a trader, and how to read it, is covered under Signals.
This detector tracks the size resting at every level of the book and flags limit orders that stand out sharply against the pair's remaining liquidity. It weighs more than dollar size: how many minutes the wall has been standing, whether it is growing or melting, how far it sits from the current price, and how much volume the pair actually turns over. An order parked hundreds of percent away from the market never reaches you.
Key tell: large size that stays put
An algorithm gives itself away by rhythm, not by size. This detector looks for series in the trade feed with a repeating period and a stable slice size — something a human does not do by hand. Three kinds are distinguished: steady periodic flow, flow with a drifting size but a strict cadence, and a fast burst of identical trades in a row.
Key tell: an identical rhythm, not an identical amount
This detector works at tick level. It registers a price move of 2% or more within seconds, then waits to see whether price comes back at least halfway. No return means a trend, not a sweep — and no signal. It also checks that real volume was behind the move, rather than a single trade on a thin book.
Key tell: not the size of the move, but its speed and return
The most structural of the four. The detector remembers a large wall, waits for aggressive trades to touch it for the first time, and then watches for a new density appearing just beyond it on the same side. If one appears, somebody is walking the price along. Market-maker grids are excluded separately: mirrored, equal-size orders on both sides of the book are ordinary quoting, not pushing.
Key tell: the wall gets touched — and propped up by a new one
Real and unreal
Placing a large limit order costs nothing, and it can be pulled a second before price reaches it. So the bare fact that "there's a million sitting in the book" means very little on its own — what matters is how that size behaves over time.
We keep the history of every level, so we see how a wall ended: eaten by trades, or pulled untouched. Market-maker grids are recognised separately — when both sides of the book hold mirrored, equal-size orders, that is not a fight over a level but routine quoting, and those events never reach you. In the alert we show how many minutes the order has already been standing, so you can judge it yourself.
~53 : 1events the detectors discard for every one they publish
Coverage
The same set of detectors runs across every venue at once — from the largest pairs down to illiquid coins nobody watches by hand. Spot and futures are processed separately: their mechanics differ, and so does the meaning of the same level on each.
SpotFutures
Trading
Clicking a level in the book places an order at that price. No switching to the exchange and hunting for the pair again: you see the wall and trade against it in the same window.
A $50,000 account in your browser. Orders fill against the real order book, but nothing reaches the exchange. No keys needed, and you can reset the account at any time.
On by default, no keys required
Your own Binance API keys — futures and spot. The order goes to the exchange in your name, and positions and balance come back from the exchange's own response. HyperLiquid and Bybit futures are opening gradually. You pick the mode — the terminal starts in demo.
Binance Futures · Binance Spot
Your keys stay yoursThe API key is encrypted with your passphrase and stored only in this browser. It never reaches our server — we physically cannot read it, which means we cannot trade on your behalf. After a reload you enter the passphrase to unlock it.
HyperLiquid, Bybit and other exchanges — comingReal orders currently run on Binance — futures and spot. HyperLiquid and Bybit futures are opening gradually: once they are on for you, they appear in the “API — exchanges” window. Other venues are being added as they are ready; demo mode already works on every card.
The live terminal is open to everyone for 10 minutes a day with no signup. A free account removes that limit for good: no card, no paid plans, and no trial period either — there is nothing to pay for.
Create a free accountHonest about the limits
We show facts about market structure, not opinions about it. Worth saying plainly, because screeners are often expected to do otherwise.
The order book is the live list of every limit order to buy and sell a coin, with prices and sizes. A wall (or "density") is a large order that stands out clearly against the rest of the liquidity. While it is there, price struggles to pass through it: it acts as a barrier, and for traders as both a reference point and a magnet.
HookScreener connects directly to the trade and order-book WebSocket streams of 10 exchanges — no middlemen, no aggregators, no scheduled REST polling. The exchange pushes an event the moment it happens; from event to alert in the terminal takes 3–5 seconds.
A normal screener works with finished candles: price, volume, change over a period. It sees the result of a move. HookScreener works one layer below — with the orders and the trade feed themselves — so it sees the cause: who placed size, who pulled it, who is pouring volume with an algorithm. Those events are often over before a one-minute candle even closes.
Binance, Bybit, OKX, Gate.io, Bitget, MEXC, KuCoin, Kraken, HyperLiquid and AsterDEX — spot and futures, over 9,600 coins in total. Spot and futures markets are processed separately.
Because most of what it finds is noise. Market-maker grids, repeats of a single event, and orders sitting hundreds of percent from the current price are filtered out before publication. The job is not to show as much as possible — it is to remove what isn't worth your attention.
No. HookScreener shows facts about market structure: where size is resting, where an algorithm is working, where liquidity was swept. The decision stays with you. We deliberately give no buy or sell recommendations and make no price forecasts.
No — the terminal runs straight in the browser, the same on Windows, macOS and Linux. There is nothing to install, and signals are also delivered through the Telegram bot.
HookScreener is completely free right now: no trial period and no paid plans. Without an account the terminal is open 10 minutes a day, and a free account removes that limit permanently — no card required.
Yes, if you are willing to learn how to read an order book. The signals describe market structure rather than ready-made trades, so they pay off more once you understand what resting limit size means. Our blog guides are a good starting point — they are written without jargon.
Next
Full guides on reading the order book and on each signal type live in the blog.
The terminal runs in your browser — nothing to install.
Create a free accountOr open the terminal without signing up
