Market mapping - OpenPX

A prediction market on the unified surface. Prices are YES probabilities in [0, 1]. Every field is one of three entry types — direct (taken from upstream), synthetic (computed by OpenPX), or omitted (not exposed upstream).

Coverage

Exchange	Direct	Synthetic	Omitted
kalshi	13	8	4
polymarket	18	7	0

Field crosswalk

Unified field	Type	kalshi source	polymarket source	Notes
`openpx_id`	string	synthetic	synthetic	kalshi: Composite key `\{exchange\}:\{ticker\}`. polymarket: Composite key `\{exchange\}:\{ticker\}`.
`exchange`	string	synthetic	synthetic	kalshi: Literal string `"kalshi"`. polymarket: Literal string `"polymarket"`.
`ticker`	string	`Market.ticker`	`Market.slug`	kalshi: Native Kalshi market ticker. polymarket: Polymarket slug; stable, human-readable identifier (numeric id lives in `numeric_id`).
`numeric_id`	string?	omitted	`Market.id`	kalshi: Kalshi has no separate numeric id surface. polymarket: Polymarket numeric DB id used for REST deep-links.
`event_ticker`	string?	`Market.event_ticker`	synthetic	kalshi: Native Kalshi event ticker. polymarket: Read from the embedded `events[0].slug` (falls back to `events[0].id`).
`title`	string	synthetic	`Market.question`	kalshi: Composed as `\{yes_sub_title\} \| \{no_sub_title\}`. polymarket: Polymarket market question text.
`rules`	string?	synthetic	`Market.description`	kalshi: Composed as `\{rules_primary\} \| \{rules_secondary\}`. polymarket: Polymarket market description.
`status`	MarketStatus	synthetic	synthetic	kalshi: Mapped from Kalshi’s `status` enum (initialized/active/closed/determined/…) to unified `MarketStatus`. polymarket: Combined from the `active`/`closed`/`archived` booleans into unified `MarketStatus`.
`market_type`	MarketType	synthetic	synthetic	kalshi: Mapped from Kalshi’s `market_type` enum (binary/scalar) to unified `MarketType`. polymarket: Derived from `outcomes.len()` — binary if 2, otherwise categorical.
`outcomes`	array	synthetic	synthetic	kalshi: Two entries (`Yes`/`No`); price computed from `yes_ask_dollars`/`last_price_dollars`. polymarket: Zipped element-wise from the stringified-JSON arrays `outcomes`, `outcomePrices`, `clobTokenIds`.
`condition_id`	string?	omitted	`Market.conditionId`	kalshi: Kalshi has no CTF condition id. polymarket: On-chain CTF condition id.
`volume`	number (double)	`Market.volume_fp`	`Market.volumeNum`	kalshi: FixedPointCount string parsed to f64 USD. polymarket: Lifetime volume in USD.
`volume_24h`	number? (double)	`Market.volume_24h_fp`	`Market.volume24hr`	kalshi: FixedPointCount string parsed to f64 USD. polymarket: 24-hour volume in USD.
`last_trade_price`	number? (double)	`Market.last_price_dollars`	`Market.lastTradePrice`	kalshi: Fixed-point dollar string parsed to YES probability in [0, 1]. polymarket: Already a YES probability in [0, 1].
`best_bid`	number? (double)	`Market.yes_bid_dollars`	`Market.bestBid`	kalshi: Fixed-point dollar string parsed to YES probability in [0, 1]. polymarket: Already a YES probability in [0, 1].
`best_ask`	number? (double)	`Market.yes_ask_dollars`	`Market.bestAsk`	kalshi: Fixed-point dollar string parsed to YES probability in [0, 1]. polymarket: Already a YES probability in [0, 1].
`tick_size`	number? (double)	`Market.price_ranges`	`Market.orderPriceMinTickSize`	kalshi: Smallest `step` across all tiers in the `price_ranges` array. polymarket: Single scalar tick size.
`min_order_size`	number? (double)	synthetic	`Market.orderMinSize`	kalshi: 1.0 by default, 0.01 when `fractional_trading_enabled`. polymarket: Polymarket minimum order size in contracts.
`open_time`	string? (date-time)	`Market.open_time`	`Market.startDate`	kalshi: RFC3339 string parsed to UTC. polymarket: ISO 8601 string parsed to UTC.
`close_time`	string? (date-time)	`Market.close_time`	`Market.endDate`	kalshi: RFC3339 string parsed to UTC. polymarket: ISO 8601 string parsed to UTC.
`created_at`	string? (date-time)	`Market.created_time`	`Market.createdAt`	kalshi: RFC3339 string parsed to UTC. polymarket: ISO 8601 string parsed to UTC.
`settlement_time`	string? (date-time)	`Market.settlement_ts`	`Market.closedTime`	kalshi: RFC3339 string parsed to UTC. polymarket: On-chain settlement time, populated only after the market resolves.
`neg_risk`	boolean?	omitted	`negRisk` (spec gap)	kalshi: Kalshi has no neg-risk concept. polymarket: Spec gap: `negRisk` is present on every live `/markets` row but undeclared on `Market` in the gamma OpenAPI.
`neg_risk_market_id`	string?	omitted	`negRiskMarketID` (spec gap)	kalshi: Kalshi has no neg-risk concept. polymarket: Spec gap: present on every live `/markets` row but undeclared on `Market` in the gamma OpenAPI.
`result`	string?	`Market.result`	synthetic	kalshi: Native Kalshi resolution enum string. polymarket: Winning `outcomes[i]` where `outcomePrices[i] == 1.0` after settlement.

Source specs

kalshi · schema/upstream/kalshi.openapi.yaml
polymarket · schema/upstream/polymarket-gamma.openapi.yaml

Tables are auto-generated from schema/mappings/. CI fails if any direct ref no longer resolves in the cached upstream spec; the daily upstream-refresh PR surfaces drift here.