02 / SCHEMA

Know what each row means before it enters a model.

A compact field reference for the four tables used in a typical Polymarket BTC 5m / 15m order-book backtest.

Ticks / best quotes

A ticks row is written when all four best quotes exist and at least one best quote changes. It is event-driven, not a fixed-frequency sample.

Field	Meaning
`ts / ts_sec / datetime`	Collection timestamp in multiple convenient forms.
`event_slug`	Market event key used to join all related records.
`poly_up_bid / ask`	Best bid and ask for the UP token.
`poly_down_bid / ask`	Best bid and ask for the DOWN token.
`up_mid / down_mid`	Midpoint derived from the corresponding best bid and ask.
`up_spread / down_spread`	Best ask minus best bid.
`window_start_ts / window_end_ts`	Market window boundaries; 5m uses 300 seconds and 15m uses 900 seconds.
`offset_s`	Seconds relative to the market window start.

Depth rows describe one outcome and one side at one price level. A complete snapshot can contain two outcomes × two sides × up to 20 levels.

Field	Meaning
`event_slug`	Market key used to join metadata and outcomes.
`outcome`	UP or DOWN.
`side`	BID or ASK.
`level`	1-based book level; level 1 is the best available level.
`price`	Displayed token price at this level.
`size`	Displayed token size, not guaranteed execution volume.
`window_start_ts / window_end_ts`	Market window boundaries.
`offset_s`	Seconds relative to the market window start.

market_outcomes contains post-event labels: winner_side and target, where UP maps to 1 and DOWN maps to 0.

seen_markets contains market_id, condition_id, UP/DOWN asset IDs, and the window timing needed to connect an event to its market records.

Do not use winner_side or target as a predictive feature. They are labels available only after the market resolves.