selection_key

What it is

A selection_key identifies one outcome within a market, such as one team, the draw, or one side of a line. It is stable while the selection's name, player, line, direction and period do not change, and it is the same key the WebSocket uses in changes.

label is for display (Carlton Blues -6.5); the key is for joining.

It is one scheme everywhere: the key is a hash of the market and the selection's identity after every book's wording is matched to it, so "PHI Phillies" and "Philadelphia" share a key. The same key appears on /odds, /history and the WebSocket, and it does not change when the event finishes. Join a /history series to a closing price on it.

Markets and selections

• market is a stable key such as head_to_head or line: the same key means the same bet on every book.
• Inside a market, every book's price for one outcome sits under one selection, keyed by book in prices.
• When a line moves (say -6.5 to -7.5) that is a different selection with a different key.