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The full, machine-generated changelog is on GitHub. This page summarizes user-facing releases.

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Unreleased

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Breaking

  • market_id parameter renamed to market_ticker across the REST surface. Every trait method, request struct (OrderbookRequest, PriceHistoryRequest, TradesRequest, OrderbookHistoryRequest, MidpointRequest, UserTradesRequest, NewOrder, FetchOrdersParams), and unified output model (Order, Position, Fill, MarketTrade, Orderbook, OrderbookSnapshot, UserTrade) now uses market_ticker to make explicit that the value is a unified ticker (Kalshi market ticker / Polymarket slug) — never a numeric id. WebSocket layer keeps market_id (WsUpdate::{Snapshot,Delta,Clear}, SessionEvent::BookInvalidated, ActivityTrade, ActivityFill) since the streamed value is the parent condition_id on Polymarket, not a ticker. FetchMarketsParams.tickers renamed to market_tickers for the same reason. Polymarket.neg_risk_market_id is unchanged (Polymarket-specific internal id).
  • fetch_event, fetch_events, fetch_series, fetch_series_one removed; replaced by fetch_market_lineage(ticker) -> MarketLineage { market, event, series }. One call returns the market plus its parent event and series; event and series are Option, so a dangling parent reference yields None rather than failing the whole call. Kalshi pays 1–3 sequential round-trips (market → event → series); Polymarket pays 2 (the event payload embeds the parent series).
  • Event and Series identifier rename — id/slug collapsed into ticker; Polymarket numeric REST ids move to numeric_id. Matches the discipline already in place on Market. Also: Event.series_id → Event.series_ticker; Event.market_ids → Event.market_tickers. Numeric event/series ids on Polymarket now live on numeric_id (None on Kalshi).
  • EventsRequest and SeriesRequest removed along with the four trait methods; ExchangeInfo flags has_fetch_event, has_fetch_events, has_fetch_series, has_fetch_series_one collapsed into has_fetch_market_lineage.
  • fetch_market removed; fetch_markets now handles single- and multi-ticker lookups. Pass tickers: ["…"] (a Vec<String> of Kalshi tickers or Polymarket slugs) for an explicit lookup — single round-trip, no pagination. Kalshi calls /markets?tickers=…; Polymarket calls /markets?slug=…&slug=….
  • FetchMarketsParams.series_id renamed to series_ticker. Slug-semantic on both venues. Kalshi continues to filter by series ticker upstream; Polymarket ignores this field for now and will gain support via a future series_numeric_id field that maps to Polymarket’s numeric series id.
  • FetchMarketsParams.event_ticker is slug-only on Polymarket. Numeric event ids are no longer accepted and will be supported via a future event_numeric_id field. Kalshi event tickers are unchanged.
  • Polymarket CLOB V2 + pUSD migration (cutover 2026-04-28 ~11:00 UTC) — no V1 backward compatibility. The OpenPX Polymarket adapter now depends on polymarket_client_sdk_v2 = "=0.5.1" and signs orders against the V2 EIP-712 domain (version: "2"). The order struct drops nonce, feeRateBps, and taker; adds timestamp (ms), metadata (bytes32), and builder (bytes32). Trading collateral is now pUSD (not USDC.e); approvals + balance reads target 0xC011a7E12a19f7B1f670d46F03B03f3342E82DFB. V1 builder-promotion (HMAC headers on order signing) is removed; builder attribution moves into the signed order’s builder field via SdkConfig::builder().builder_code(...). Relayer POLY_BUILDER_* HMAC headers are preserved for gasless tx auth (per the Polymarket migration guide). (#54)

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Added

  • core: 14 new unified Exchange trait methods scaffolded (default Err(NotSupported)); per-venue impls land in follow-up PRs. New surface: fetch_events, fetch_event, fetch_series, fetch_series_one, fetch_market_tags, fetch_orderbooks_batch, fetch_midpoint, fetch_midpoints_batch, fetch_spread, fetch_last_trade_price, fetch_open_interest, fetch_user_trades, cancel_all_orders, create_orders_batch. New models: Event, Series, SettlementSource, Tag, Spread, LastTrade, UserTrade. New request types: EventsRequest, SeriesRequest, MidpointRequest, UserTradesRequest, NewOrder. (#56)
  • core: Exchange::fetch_server_time() returns each venue’s wall-clock as DateTime<Utc> for clock-skew correction in signing-sensitive paths. ExchangeInfo gains has_fetch_server_time: bool. (#26)

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Fixed

  • sdk: TypeScript models.d.ts was a 13-line empty stub; the codegen now emits all 35+ interfaces (ExchangeInfo, Market, Fill, WsUpdate, OrderStatus, and more). (#34)

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0.2.6 — 2026-04-24

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Breaking

  • Polymarket Market.id is now the condition_id hex string (e.g. 0x311d0c4b…), not the numeric REST id. Callers that need the numeric id should read Market.native_numeric_id instead.

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0.2.5 — 2026-04-23

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Breaking

  • WsUpdate::Snapshot.market_id and Delta.market_id carry the parent condition ID on Polymarket (not the CLOB token). Consumers keying by market_id expecting a token should switch to the new asset_id field.
  • Kalshi fetch_markets cursor format changed. Old 0.2.3 cursors are rejected; restart pagination after upgrading.

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Added

  • New WsUpdate::Clear variant with InvalidationReason for per-market book invalidation on the same stream as Snapshot/Delta.
  • Reconnect parity across all exchanges.

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Fixed

  • Kalshi fetch_markets rewritten on /markets + /historical/markets.

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0.2.0 — 2026-04-22

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Breaking

  • WebSocket surface rewritten. Per-token orderbook_stream(token_id) and activity_stream(token_id) are gone. Consumers now read ws.updates() (multiplexed WsUpdate) and ws.session_events() (connection-level SessionEvent).
  • Both stream methods are take-once — calling either twice returns None (Rust) or raises (Python/TS).
  • WsUpdate::Raw removed. Untyped escape-hatch variant retired.
  • Timestamps unified to u64 millis on the entire WS surface.
  • Python WS variants are real classes (Snapshot, Delta, Trade, Fill, Connected, Reconnected, Lagged, BookInvalidated, SessionError) — not dicts. match and isinstance work directly.
  • tokio::sync::broadcast replaced with async-channel plus explicit Lagged + BookInvalidated signaling.

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Earlier versions

See the full changelog on GitHub for 0.1.x and 0.2.1 – 0.2.4.