fill_id | string | Fill.fill_id | Trade.transactionHash | kalshi: Kalshi-issued unique fill id. polymarket: Polygon transaction hash; doubles as fill id since one trade lands per tx. |
order_id | string | Fill.order_id | omitted | kalshi: Kalshi-issued order id that produced this fill. polymarket: Public-tape Trade does not expose order ids; live WebSocket events do via liquidity_role. |
market_ticker | string | Fill.ticker, fallback Fill.market_ticker | Trade.conditionId | kalshi: Prefers canonical ticker, falls back to legacy alias market_ticker. polymarket: On-chain condition id; Position.market_ticker (slug) intentionally diverges from this surface. |
outcome | string | Fill.side | Trade.outcome | kalshi: Title-cased from the YES/NO side field (buy/sell lives on action). polymarket: Outcome label as published by Polymarket. |
side | OrderSide | Fill.action | Trade.side | kalshi: Buy/Sell sourced from action (the YES/NO side field is unrelated). polymarket: BUY/SELL enum, 1:1 with unified OrderSide. |
price | number (double) | Fill.yes_price_dollars, fallback Fill.no_price_dollars | Trade.price | kalshi: Outcome-aware: uses yes_price_dollars on YES fills and no_price_dollars on NO fills. polymarket: Decimal probability for the row’s outcome token in [0, 1]. |
size | number (double) | Fill.count_fp | Trade.size | kalshi: FixedPointCount string parsed to f64. polymarket: Non-negative size in contracts. |
is_taker | boolean | Fill.is_taker | omitted | kalshi: Boolean: true if the fill removed liquidity, false if it added. polymarket: Public tape lacks per-fill maker/taker flag; the WebSocket user channel carries liquidity_role. |
fee | number (double) | Fill.fee_cost | omitted | kalshi: Per-fill fee in FixedPointDollars. polymarket: Polymarket does not expose a per-fill fee on the Data API; defaults to 0.0. |
created_at | string (date-time) | Fill.created_time | Trade.timestamp | kalshi: RFC3339 string parsed to UTC. polymarket: Unix seconds (not milliseconds) parsed to UTC. |
