Building VisualHFT Terminal: the observability and decision terminal for quantitative and electronic trading desks.
Miami, FL
Joined November 2023
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Price follows the side of the book that refuses to refill.
When aggressive flow hits a book, depth rarely replenishes symmetrically.
VisualHFT's Market Resilience Bias tile tracks queue refill asymmetry in real time, firing a directional arrow the second one side refuses to stand.
visualhft.com/blog/from-sign…
VisualHFT retweeted
The same reject message can mean slow down or stop.
Euronext, on throttling: "In FIX, clients receive Reject (3) messages". Breach the limit badly and you "won't be allowed to reconnect for 3 seconds".
The FIX 4.2 dictionary says a Reject "indicates a serious error that may be the result of faulty logic in either the sending or receiving application".
Coinbase Exchange: "Your FIX 5 session is disconnected if your messages exceed 200 messages per second".
Send your handler a Reject (3) with tag 373=26. Does it back off or stop?
More in chapter 24 of my book, The Electronic Trading Stack.
AMZN, 22 Aug 2023: sell pressure went from -22 to -98.6 in seconds. The scale stops at -100.
VisualHFT Terminal puts the sellers' push in one number, -100 to +100, so you size quotes to the market you are in.
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The NFLX mid ticked up with zero trades on the tape. New bids at the touch moved it.
VisualHFT Terminal shows OFI turning positive with book and tape on one screen, so you see a quote-only move before you lean on displayed size.
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VisualHFT retweeted
How Do I Design High-Frequency Trading Systems and Its Architecture.
Part 1 of 3
(this is a 2026 Update from a previous post)
The architectural principles still hold in 2026. What has shifted is the protocol landscape, the C++ memory toolkit, and a couple of LOB-layout refinements.
electronictradinghub.com/how…
Buyers crossed the spread, and the price did not move.
Delta of Trades jumps on buys at the offer while OFI stays near zero, and the offer holds. The Desk in VisualHFT Terminal shows the tape pushing and the book standing still, so you see it before you chase.
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AMZN, 22 Aug 2023: sellers ended 10 seconds net 6,778 shares through the bid. Here is the tape.
Delta of Trades in VisualHFT Terminal nets buy-taker against sell-taker size, and its footer shows how much had a side, so you know which side is paying the spread now.
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VisualHFT retweeted
Hudson River Trading has started trading on prediction markets
It's not touching sports and its trades have included up-down markets so far. HRT was also an investor in Kalshi's latest $1b fundraising round.
Scoop today with @DavidPan_1 and @KatLeighDoherty: bloomberg.com/news/articles/…
CVD reads positive while sellers do the hitting, and both are true at once.
The sign is the session and the slope is now. The CVD tile in VisualHFT Terminal shows both, so an early buying run never hides who is selling into you now.
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Mid: unchanged. Book: already leaning up.
OFI in VisualHFT Terminal plots the lean at the best bid and ask against the mid on one time axis. When it turns against the quote you are resting, you decide to stay or pull while the price still holds.
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Nine seconds of AMZN bids building, then six cents gone in 1.3 seconds. Watch OFI flip red.
OFI in VisualHFT Terminal swung from green to red on the way down, so you stop leaning on size that already left.
#visualhft
Sellers hit the bid, OFI drops through zero, and the AMZN mid falls 15 cents.
VisualHFT Terminal's Order Flow Dynamics Desk shows the book's lean and the tape in one view, so you see both turn down together before you place a quote.
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79.7%: how often the side of the last trade called the direction of the next mid change on held-out NASDAQ data.
It beat a last-tick reversal rule by more than 40 points.
The Order Flow Dynamics Desk is live in VisualHFT Terminal: taker flow beside the book's lean.
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We could have sold you a pull-your-orders trigger. Our hold-out data said no.
Read causally, the fill-cost effect flipped sign, so TTO in VisualHFT Terminal does the job it earned: putting the sweep on your screen while it happens.
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25 orders for every trade. That was Vertex's book while the price fell 16 cents in 7.6 seconds.
One Trigger Engine rule in VisualHFT Terminal turns that spike into a webhook, so your system widens its tolerances on its own.
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VisualHFT retweeted
Kraken status
Kraken has an unresolved service issue. Monitoring for a confirmed resolution.
When the book churns, the size on the offer is a guess.
Hasbrouck and Saar showed a large share of limit orders are fleeting: cancelled within seconds, never traded. OTR in VisualHFT Terminal flags that churn, so widen your tolerances while it lasts.
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VisualHFT retweeted
OTR spikes, then above-normal mid volatility: 69.8% of the time on held-out symbols. Random moments: 49.9%.
A churning book warns you about the next 10 seconds, and VisualHFT Terminal shows the risk before the quotes start to fly.
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Orders churn and nothing prints: OTR climbs. Prints eat displayed depth: TTO jumps.
Keep both tiles side by side in VisualHFT Terminal and know whether the book you quote into is being quoted or traded through.
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Quiet tape lights the TTO tile 2.7% of the time. Sweeps: 22.4%.
Across 14 NASDAQ symbols and one full day, TTO in VisualHFT Terminal reached its daily top 10% and held there, so many sweeps stand out at a glance.
#visualhft
OTR spikes, then above-normal mid volatility: 69.8% of the time on held-out symbols. Random moments: 49.9%.
A churning book warns you about the next 10 seconds, and VisualHFT Terminal shows the risk before the quotes start to fly.
#visualhft