/trade/chain is the options chain — the wall of numbers professional options traders stare at all day. Calls on the left, puts on the right, strikes ascending in the center, delta and IV readings at every strike. It looks like a flat data dump and is actually a structured information graph; learning to read it is the difference between gambling on options and trading them.

An options chain is the complete map of what's tradeable for a stock at a given expiration. Every row is a strike price; every column is a piece of information at that strike (bid, ask, volume, open interest, implied volatility, delta, gamma, theta, vega). Calls are tabulated on one side; puts on the other; strikes sit in the middle, sorted ascending.

In-the-money strikes (calls below spot, puts above spot) are highlighted because they have intrinsic value; out-of-the-money strikes are time-value-only.