The Runtime Theory
medium · 4h · 8 steps

High-Frequency Trading Intermediate

Matching engines, market data feeds, and order book dynamics — building the systems that power modern trading venues.

Curriculum (8 steps)

1

A market where buyers and sellers exchange assets. Learn about exchanges, order books, bids, asks, and how prices are discovered.

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2

Limit orders vs market orders, how they fill, and how the order book depth works.

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3

Visual map of an order book showing bids, asks, spread, and depth at multiple price levels.

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4

Follow a market order as it arrives at the exchange, matches against the top of the order book, and produces a trade.

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5

Given a sequence of market orders and an order book state, determine which orders fill at which prices.

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6

How exchanges match buy and sell orders using price-time priority, pro-rata allocation, and lock-free data structures.

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7

How exchanges broadcast real-time market data, the FIX and ITCH protocols, and how feed handlers parse data at line rate.

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8

The difference between taking and making liquidity, why latency matters in microseconds, and the concept of marketable vs non-marketable orders.

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