Start here
Eighty terms is a lot to walk into. This is the order I would read them in, and the reason for the order. Six entries, perhaps an hour. After that the rest of the site stops being a wall of vocabulary.
Almost every confusion further along traces back to one of the first three being half-understood. They are worth going slowly on.
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01
The aggressor
Start here because every order flow measurement is an attempt to answer one question: which side crossed the spread. Every trade has exactly one aggressor and one participant who was already waiting. Separating those two roles is the whole discipline.
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02
Bid and ask
The two nearest standing intentions in the market, and the gap between them. Not the price of the instrument — there is no trade at all until one side agrees to the other’s terms. Once this is clear, limit and market orders stop being jargon and become two obvious choices.
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03
Delta
Volume traded at the ask minus volume traded at the bid. This is where most people first go wrong, because it measures net aggression rather than net buying, and net buying is impossible — every contract bought was simultaneously sold. Get this right and half the internet’s order flow commentary becomes visibly confused.
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04
The footprint chart
Everything above, made visible. A footprint does not add information to the tape; it rearranges it so the distribution of activity within a bar stops being discarded. Once you can read one cell, imbalance, absorption and exhaustion are all descriptions of patterns across cells.
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05
Contract specification
A change of subject, and a necessary one. What a futures contract actually specifies, what a tick is worth, and what margin really is. These are the numbers that turn a chart into money, and they differ for every instrument. Skipping them is expensive.
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06
Premium
The entry point to options. What you are paying for, split into the part that has value now and the part that is a price on uncertainty. From here, moneyness, time decay and implied volatility all follow naturally.
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07
Dealer hedging
One step past options, and the mechanism the whole options flow section rests on. A dealer who takes the other side of your trade does not want your view, so they offset it in the underlying and keep adjusting. That obligation is mechanical, and it is large.
Then what
Take the sections in this order: The Tape, The Contract, The Right, The Hedge. Options flow depends on options, which depend on contract mechanics, which are easiest to see in futures.
The Feed can be read at any point and is worth reading earlier than feels natural. It covers where the numbers come from and why two platforms disagree about the same session, which will save you from a category of confusion that otherwise takes months to resolve on its own.
Two things to read once
The Column explains why this site publishes no strategies, and why that refusal is the useful part rather than a limitation. The Pitch covers the industry that has grown up around retail trading, what makes a method profitable in the first place, and the standard ways a backtest lies.
Neither will tell you what to do. That is the point.
How the entries are written
Every one opens with a one-sentence definition that stands alone, then explains what the thing measures, then how it is calculated, then where it misleads. That last section is not a formality. A measurement you understand the failure modes of is a tool; the same measurement without them is a superstition with a chart attached.
If you only ever read one part of each page, read the limitations.