feat: add batch 4 API updates - UserOrders WS channel, subaccount filters, market_id

- Add UserOrders WebSocket channel with UserOrderData and UserOrderEventType
  for real-time order update streaming (created, updated, canceled, executed)
- Add subaccount filter to ListRfqsParams for per-subaccount RFQ queries
- Add subaccount parameter to order group read endpoints (GetOrderGroupsParams,
  get_order_group) and get_order_group_for_subaccount() client method
- Add market_id field to IncentiveProgram

Author: pbeets

API_CHANGES_TODO.md

@@ -323,99 +323,31 @@ pub enum MarketResult {
 
 ---
 
-## BATCH 4: January 30 – February 5, 2026
+## ~~BATCH 4: January 30 – February 5, 2026~~ ✅ DONE
 
-### 4.1 — Queue Position Fixed-Point Field
+### ~~4.1 — Queue Position Fixed-Point Field~~ ✅
 
-**Changelog**: Jan 30, 2026 — "Order queue position returns fixed point field"
+Already implemented in batch 1 (`queue_position_fp` on `QueuePosition` and `OrderQueuePositionResponse`).
 
-**What changed**: `queue_position_fp` field added to queue position responses.
+### ~~4.2 — Subaccount Support for RFQs~~ ✅
 
-**What to do**:
-- Add `queue_position_fp: Option<String>` to queue position response types in order-related models
-- Check `OrderQueuePositionResponse` and `QueuePositionsResponse`
-
-**Files to modify**: `src/models/order.rs` (or wherever queue position types live)
-
----
-
-### 4.2 — Subaccount Support for RFQs
-
-**Changelog**: Feb 2, 2026 — "Subaccount support for RFQs"
-
-**What changed**:
-- `POST /communications/rfqs` accepts optional `subaccount` parameter
-- `GET /communications/rfqs` accepts optional `subaccount` query parameter
-
-**What to do**:
-- Add `subaccount: Option<i32>` to `CreateRfqRequest` in `src/models/communications.rs`
-- Add `subaccount: Option<i32>` to RFQ list query params
+`CreateRfqRequest.subaccount` was implemented in batch 2. Added `subaccount` filter to `ListRfqsParams`.
 
-**Files to modify**: `src/models/communications.rs`, `src/api/communications.rs`
+### ~~4.3 — Subaccount Support for RFQ Quotes~~ ✅
 
----
-
-### 4.3 — Subaccount Support for RFQ Quotes
-
-**Changelog**: Jan 22, 2026 — "Subaccount support for RFQ quotes"
-
-**What changed**: `POST /communications/quotes` accepts optional `subaccount` parameter.
-
-**What to do**:
-- Add `subaccount: Option<i32>` to `CreateQuoteRequest` in `src/models/communications.rs`
+Already implemented in batch 2 (`CreateQuoteRequest.subaccount`).
 
-**Files to modify**: `src/models/communications.rs`
+### ~~4.4 — User Orders WebSocket Channel~~ ✅
 
----
+Added `UserOrders` channel, `UserOrderData`, `UserOrderEventType`, message parsing.
 
-### 4.4 — User Orders WebSocket Channel
+### ~~4.5 — Order Group Read Endpoints Subaccount Parameter~~ ✅
 
-**Changelog**: Feb 3, 2026 — "User orders WebSocket channel"
+Added `subaccount` to `GetOrderGroupsParams` and `get_order_group()` API function. Added `get_order_group_for_subaccount()` to client.
 
-**What changed**: New `user_orders` channel streams real-time order updates (created, updated, canceled, executed) for authenticated users. Supports optional `market_tickers` filter and dynamic `update_subscription` commands.
-
-**What to do**:
-- Add `UserOrders` variant to `Channel` enum in `src/ws/channel.rs`:
-  - Wire name: `"user_orders"`
-  - Requires auth: yes
-  - Does NOT require market ticker (supports optional tickers)
-- Add `UserOrderData` struct in `src/ws/message.rs`:
-  - Should mirror the `Order` REST type or have relevant order fields
-  - Include event_type (created, updated, canceled, executed)
-- Add `UserOrder(UserOrderData)` variant to `StreamMessage`
-- Update message parsing
-- Update `Channel::requires_auth()`
-- Export new types
-
-**Files to modify**: `src/ws/channel.rs`, `src/ws/message.rs`, `src/lib.rs`
-
----
-
-### 4.5 — Order Group Read Endpoints Subaccount Parameter
-
-**Changelog**: Feb 3, 2026 — "Order group read endpoints support optional subaccount parameter"
-
-**What changed**: `GET /portfolio/order_groups` and `GET /portfolio/order_groups/{id}` accept optional `subaccount` query parameter.
-
-**What to do**:
-- Add `subaccount: Option<i32>` to order group list params
-- Add optional `subaccount` query param to single order group get
-- Update `src/api/order_groups.rs` and `src/client.rs`
-
-**Files to modify**: `src/models/order_group.rs`, `src/api/order_groups.rs`, `src/client.rs`
-
----
-
-### 4.6 — `market_id` on Incentive Programs API
-
-**Changelog**: Feb 5, 2026 — "market_id added to Incentive Programs API"
-
-**What changed**: `GET /incentive_programs` now returns `market_id` field.
-
-**What to do**:
-- Add `market_id: Option<String>` to `IncentiveProgram` in `src/models/incentive_program.rs`
+### ~~4.6 — `market_id` on Incentive Programs API~~ ✅
 
-**Files to modify**: `src/models/incentive_program.rs`
+Added `market_id: Option<String>` to `IncentiveProgram`.
 
 ---
 

CHANGELOG.md

@@ -83,6 +83,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `with_selected_markets()` constructor on `CreateMarketInCollectionRequest` and
   `LookupTickersRequest`.
 - `lookback_seconds` filter on `GetLookupHistoryParams`.
+- New `UserOrders` WebSocket channel for real-time order update notifications
+  (`UserOrderData`, `UserOrderEventType`). Requires authentication, supports
+  optional `market_tickers` filtering.
+- `subaccount` filter on `ListRfqsParams` for per-subaccount RFQ queries.
+- `subaccount` filter on `GetOrderGroupsParams` for per-subaccount order group
+  queries. New `get_order_group_for_subaccount()` method on `KalshiClient`.
+- `market_id` field on `IncentiveProgram`.
 
 ### Fixed
 

src/api/order_groups.rs

@@ -27,8 +27,16 @@ pub async fn create_order_group(
 pub async fn get_order_group(
     http: &HttpClient,
     order_group_id: &str,
+    subaccount: Option<i32>,
 ) -> Result<GetOrderGroupResponse> {
-    let path = format!("/portfolio/order_groups/{}", encode_id(order_group_id));
+    let path = match subaccount {
+        Some(sub) => format!(
+            "/portfolio/order_groups/{}?subaccount={}",
+            encode_id(order_group_id),
+            sub
+        ),
+        None => format!("/portfolio/order_groups/{}", encode_id(order_group_id)),
+    };
     http.get(&path).await
 }
 

src/client.rs

@@ -1021,7 +1021,21 @@ impl KalshiClient {
     /// println!("Orders: {:?}", response.orders);
     /// ```
     pub async fn get_order_group(&self, order_group_id: &str) -> Result<GetOrderGroupResponse> {
-        order_groups::get_order_group(&self.http, order_group_id).await
+        order_groups::get_order_group(&self.http, order_group_id, None).await
+    }
+
+    /// Get an order group by ID for a specific subaccount.
+    ///
+    /// # Arguments
+    ///
+    /// * `order_group_id` - The ID of the order group to retrieve
+    /// * `subaccount` - Subaccount number (0 for primary, 1-32 for subaccounts)
+    pub async fn get_order_group_for_subaccount(
+        &self,
+        order_group_id: &str,
+        subaccount: i32,
+    ) -> Result<GetOrderGroupResponse> {
+        order_groups::get_order_group(&self.http, order_group_id, Some(subaccount)).await
     }
 
     /// List all order groups with default parameters.

src/models/communications.rs

@@ -417,6 +417,10 @@ pub struct ListRfqsParams {
     /// Filter by creator user ID.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub creator_user_id: Option<String>,
+    /// Filter by subaccount number. When omitted, returns RFQs across all subaccounts.
+    /// When provided (including 0), filters to that specific subaccount.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub subaccount: Option<i32>,
 }
 
 impl ListRfqsParams {
@@ -462,6 +466,13 @@ impl ListRfqsParams {
         self
     }
 
+    /// Filter by subaccount number.
+    #[must_use]
+    pub fn subaccount(mut self, subaccount: i32) -> Self {
+        self.subaccount = Some(subaccount);
+        self
+    }
+
     #[must_use]
     pub fn to_query_string(&self) -> String {
         use crate::models::query::QueryBuilder;
@@ -472,6 +483,7 @@ impl ListRfqsParams {
         qb.push_opt("limit", self.limit);
         qb.push_opt("status", self.status.as_ref());
         qb.push_opt("creator_user_id", self.creator_user_id.as_ref());
+        qb.push_opt("subaccount", self.subaccount);
         qb.build()
     }
 }

src/models/incentive_program.rs

@@ -36,6 +36,9 @@ pub struct IncentiveProgram {
     /// Target size for the program.
     #[serde(default)]
     pub target_size: Option<i64>,
+    /// The market ID associated with this incentive program.
+    #[serde(default)]
+    pub market_id: Option<String>,
 }
 
 /// Response from GET /incentive_programs.

src/models/order_group.rs

@@ -196,6 +196,10 @@ pub struct GetOrderGroupsParams {
     /// Number of results per page.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub limit: Option<i32>,
+    /// Filter by subaccount number. When omitted, returns across all subaccounts.
+    /// When provided (including 0), filters to that specific subaccount.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub subaccount: Option<i32>,
 }
 
 impl GetOrderGroupsParams {
@@ -217,11 +221,19 @@ impl GetOrderGroupsParams {
         self
     }
 
+    /// Filter by subaccount number.
+    #[must_use]
+    pub fn subaccount(mut self, subaccount: i32) -> Self {
+        self.subaccount = Some(subaccount);
+        self
+    }
+
     #[must_use]
     pub fn to_query_string(&self) -> String {
         let mut qb = QueryBuilder::new();
         qb.push_opt("cursor", self.cursor.as_ref());
         qb.push_opt("limit", self.limit);
+        qb.push_opt("subaccount", self.subaccount);
         qb.build()
     }
 }

src/ws/channel.rs

@@ -23,6 +23,8 @@ pub enum Channel {
     MarketLifecycle,
     /// Order group lifecycle events (requires authentication)
     OrderGroupUpdates,
+    /// Real-time user order updates (requires authentication)
+    UserOrders,
     /// Multivariate collection lookup notifications
     Multivariate,
 }
@@ -32,7 +34,11 @@ impl Channel {
     pub fn requires_auth(&self) -> bool {
         matches!(
             self,
-            Self::Fill | Self::MarketPositions | Self::Communications | Self::OrderGroupUpdates
+            Self::Fill
+                | Self::MarketPositions
+                | Self::Communications
+                | Self::OrderGroupUpdates
+                | Self::UserOrders
         )
     }
 
@@ -58,6 +64,7 @@ impl Channel {
             Self::Communications => "communications",
             Self::MarketLifecycle => "market_lifecycle_v2",
             Self::OrderGroupUpdates => "order_group_updates",
+            Self::UserOrders => "user_orders",
             Self::Multivariate => "multivariate",
         }
     }