API Changelog - API Documentation

You can subscribe to the RSS changelog at /changelog.rss if you’d like to stay ahead of breaking changes. You can reference the pending API spec under the “version” dropdown menu at the top left. When the actual API is upgraded to this new version, you will see the version marked as “Stable” in the drop-down menu and become the new default on the landing page. This changelog is a work in progress. As always, we welcome any feedback in our Discord #dev channel!

Recent Updates

Jan 22, 2026

Added order_group_updates WebSocket channel to stream order group lifecycle updates (created, triggered, reset, deleted, limit_updated). Payloads include contracts_limit_fp for created and limit_updated events.New channel:

order_group_updates

Release date: January 29, 2026

Jan 21, 2026

The client_order_id and updated_client_order_id fields in amend order requests are now optional.Behavior changes:

You can now amend orders without providing client_order_id fields by using only the order_id from the URL path
If you provide an updated_client_order_id, the order can be found by the exchange and the client_order_id updated just on order_id alone

Affected endpoint:

POST /trade-api/v2/portfolio/orders/{order_id}/amend

Example:

{
  "ticker": "MARKET-TICKER",
  "side": "yes",
  "action": "buy",
  "count_fp": "50.00",
  "yes_price": 30
}

This will amend the order identified by order_id without requiring client_order_id fields.Release date: January 28, 2026

Jan 29, 2026

Release date: January 29, 2026

Jan 29, 2026

Added an endpoint to update the contracts limit for an order group (rolling 15-second window). If the updated limit would immediately trigger the group, all orders in the group are canceled and the group is triggered.New endpoint:

PUT /portfolio/order_groups/{order_group_id}/limit

Response updates:

GET /portfolio/order_groups
GET /portfolio/order_groups/{order_group_id}

Both now include contracts_limit and contracts_limit_fp.Release date: January 29, 2026

Jan 22, 2026

Added *_fp fixed-point contract count fields in the WebSocket AsyncAPI spec and examples (orderbook, ticker, trades, fills, positions, communications). See the AsyncAPI spec.Release date: January 22, 2026

Jan 21, 2026

Added updated_time to Market responses and min_updated_ts filter to GET /markets, which filters for only markets updated later than the provided unix ts.Affected endpoints:

GET /markets/{ticker}
GET /markets.

Jan 20, 2026

Currently, a market settled to a scalar result will return "" in the market_result field. Starting in the next release, this value will read "scalar" instead.Affected endpoints:

GET /markets/{ticker}
GET /markets

Release date: January 28, 2026

Jan 21, 2026

Added manual trigger support for order groups.New endpoint:

PUT /portfolio/order_groups/{order_group_id}/trigger

Release date: January 22, 2026

Jan 16, 2026

Maker RFQ client order IDs now use the format quote:<hash>:<quote_id>, where hash is an 8-character hash segment and the maker’s quote ID is added as a suffix.Release date: January 22, 2026

Jan 16, 2026

Added include_latest_before_start parameter to the single market candlesticks endpoint for price continuity.When set to true, prepends a synthetic candlestick that:

Uses the close price from the most recent candlestick before start_ts
Sets previous_price to enable continuous price charting

Affected endpoint:

GET /series/{series_ticker}/markets/{ticker}/candlesticks

Release date: January 22, 2026

Jan 15, 2026

Added *_fp string fields for contract counts across REST API requests and responses.Example order response:

{
  "count": 10,
  "count_fp": "10.00",
  "fill_count": 5,
  "fill_count_fp": "5.00"
}

See Fixed-Point Contracts for migration details.Release date: Jan 22, 2026

Jan 13, 2025

RFQ creator IDs will be exposed only after the RFQ is closed/executes. Accordingly the RFQ creator ID is removed entirely from related websocket messages that are created before this point (RFQCreated, QuoteCreated).Release date: Jan 15, 2025

Jan 13, 2025

Settlement value on component legs are now reported when pulling MVEs.Release date: January 13, 2025

Jan 12, 2026

Added sharding support to the communications WebSocket channel for high-throughput RFQ/quote consumers.New subscription parameters:

shard_factor (int): Number of shards to divide messages across (e.g., 4)
shard_key (int): Which shard this connection receives (0 to shard_factor-1)

Messages are sharded by market_ticker using consistent hashing. Clients can run multiple connections with different shard_key values to distribute load while ensuring complete coverage.Validation:

shard_factor must be > 0 when provided
shard_key must be >= 0 and < shard_factor
shard_key requires shard_factor to be set

Example subscription:

{
  "id": 1,
  "cmd": "subscribe",
  "params": {
    "channels": ["communications"],
    "shard_factor": 4,
    "shard_key": 0
  }
}

No breaking changes: When these parameters are omitted, all messages are received as before. Existing integrations are unaffected.

Jan 9, 2026

New endpoints for managing subaccounts within a user’s portfolio.New endpoints:

POST /portfolio/subaccounts - Create a new subaccount
GET /portfolio/subaccounts/balances - Get balances for all subaccounts
POST /portfolio/subaccounts/transfer - Transfer funds between subaccounts
GET /portfolio/subaccounts/transfers - Get paginated history of subaccount transfers

Note: Transfers require a unique client_transfer_id for idempotency.

Jan 9, 2025

On GET /markets, responses may bear is_provisional: true, indicating that the market will be removed from the API if it has no activity by settlement time.Notes:

Historical and existing markets are unaffected, this change only applies going forward.
A market will never transition into the provisional state if it was not created as provisional.

Expected release date: January 9, 2025.

Jan 6, 2026

Added optional volume field to Series responses showing total contracts traded across all events in the series.Affected endpoints:

GET /series - Added include_volume query parameter (default: false)
GET /series/{series_ticker} - Added include_volume query parameter (default: false)

When include_volume=true, the response includes the volume field with the total contracts traded.Release date: January 15, 2026

Jan 6, 2026

Cent-denominated price fields will be removed from Market responses.Affected endpoints:

GET /markets
GET /markets/{ticker}
GET /events
GET /events/{ticker}

Fields to be removed:

response_price_units, notional_value, yes_bid, yes_ask, no_bid, no_ask, last_price, previous_yes_bid, previous_yes_ask, previous_price, liquidity → Use *_dollars equivalents (e.g., yes_bid_dollars)
tick_size → Use price_level_structure and price_ranges

Release date: January 15, 2026

Jan 5, 2026

The deprecated fields category and risk_limit_cents will be removed from Market responses.Affected endpoints:

GET /markets
GET /markets/{ticker}

Release date: January 8, 2026

Dec 22, 2025

Search endpoints now accept lowercase query parameters for improved flexibility and consistency.Release date: December 22, 2025

Dec 19, 2025

Added settlement_ts field to GET /markets and GET /markets/{ticker} responses.Release date: December 25, 2025

Dec 16, 2025

The Market response object now documents all possible status values: initialized, inactive, active, closed, determined, disputed, amended, finalized.

Dec 13, 2025

In GET /markets, markets that have been paused by an administrator will be available under new the paused status filter.

Dec 11, 2025

GET /portfolio/settlements will return each settled position’s Event Ticker. Release Date: December 18, 2025

Dec 18, 2025

API keys now support a scopes field. Valid scopes are read and write. Keys default to full access if not specified. All existing API keys will have both scopes.Release date: December 18, 2025

Dec 5, 2025

GET /portfolio/positions will only return unsettled positions. For fetching settled market positions, switch to GET /portfolio/settlements.Release date: December 11, 2025

Dec 2, 2025

Breaking Change: GET /events excludes multivariate eventsRelease date: December 4, 2025

Dec 1, 2025

Release date: December 4, 2025

Dec 1, 2025

DELETE /portfolio/orders/batched is now generally available. Advanced API access is no longer required. (The Nov 14th update only applied to POST.)Release date: December 4, 2025

Nov 29, 2025

GET /live_data/{type}/milestone/{milestone_id} and GET /live_data/batch now returns milestone_id in the response.Release date: December 4, 2025

Nov 23, 2025

Updates to filtering in GET /markets

Inactive markets during tradable hours will returned in the open selector.
Inactive markets during tradable hours no longer appear in the closed selector.
Restricting to a single status filter allowed per request (previously announced).

Release date: November 27, 2025

Nov 21, 2025

Subpenny fields yes_bid_dollars and no_bid_dollars available on the Get Quote API. Affected endpoints:

GET /communications/quotes
GET /communications/quotes/{quote_id}

Nov 27, 2025

Adds new endpoint GET /markets/candlesticksRetrieve candlestick data for multiple markets in a single API call. Supports up to 10,000 candlesticks total across all requested markets.Expected release: November 27, 2025

Nov 21, 2025

Breaking changes to order expiration and immediate-or-cancel (IoC) handling:

Past expiration timestamps now rejected: Orders with expiration_ts in the past will be rejected with error “Expiration timestamp must be in the future” instead of being automatically converted to IoC orders.
IoC + expiration_ts combination rejected: Orders cannot specify both time_in_force: "immediate_or_cancel" and expiration_ts. This will be rejected at the API level with error “Cannot specify both immediate_or_cancel and expiration_ts”.
IoC orders no longer support expiration: The IoC order type is now independent and does not accept an expiration timestamp.

Migration guide: If you were previously using past expiration_ts values to indicate IoC behavior, you must now explicitly set time_in_force: "immediate_or_cancel" instead.Expected release: TBD

Nov 20, 2025

‘Pending’ is being removed from the status enum on ordersExpected release: November 27, 2025

Nov 14, 2025

POST /portfolio/orders/batched will now be generally available. Advanced API access is no longer a prerequisite.Release date: November 20, 2025

Nov 14, 2025

Added created_time to GET /markets && GET /market responses.Release date: November 20, 2025

Nov 11, 2025

Breaking changes planned to GET /markets endpoint for performance reasons: Timestamp filters will be mutually exclusive from other timestamp filters and certain status filters.

Compatible Timestamp Filters	Additional Status Filters
min_created_ts, max_created_ts	`unopened`, `open`, empty
min_close_ts, max_close_ts	`closed`, empty
min_settled_ts, max_settled_ts	`settled`, empty

Nov 11, 2025

Added new timestamp filters for the GET /markets endpoint:

min_created_ts
max_created_ts
min_settled_ts
max_settled_ts

Nov 7, 2025

GET /portfolio/positions will no longer return resting_orders_count in both the event_positions and market_positions field.
The resting_order_count filter on GET /portfolio/positions will no longer be supported. Requests specifying this filter will return a 400 error.

Expected release: November 13, 2025

Nov 13, 2025

GET /portfolio/settlements now returns the sum of trade fees paid by the user on a settled market position.

Nov 6, 2025

Fixed two issues with the GET /events endpoint’s limit parameter:

Default increased: The default limit is now 200 (previously 100) to return more results per page
Parameter: Requests with with_nested_markets=true now properly respect limit=200 instead of being capped at 100

Nov 6, 2025

The GET /portfolio/positions endpoint now includes total_cost_shares, which tracks the total number of shares traded on an event (including both YES and NO contracts).

Nov 6, 2025

Added comprehensive support for multivariate events (combos) with new API endpoints and enhanced filtering:New Endpoint and deprecation of multivariate events in GetEvents endpoint

GET /events/multivariate - Retrieve multivariate events with filtering by series and collection ticker.
GET /events will EXCLUDE multivariate events upon the next release (November 13th). Please use the new endpoint!

Enhanced Market Filtering:

GET /markets now supports mve_filter parameter:
- "only" - Returns only multivariate events
- "exclude" - Excludes multivariate events
- No parameter - Returns all events (default behavior)

Expected release: November 6th, 2025

Oct 24, 2025

Fixed batch order creation to return proper error details when post-only orders cross the market. The response now includes:

Error code: "invalid order"
Error details: "post only cross"

This makes the batch endpoint consistent with single order creation and provides clear feedback on why post-only orders were rejected.

Oct 20, 2025

The GET /portfolio/orders endpoint’s event_ticker parameter now supports filtering by multiple events using comma-separated values.Example usage:

GET /portfolio/orders?event_ticker=EVENT1,EVENT2,EVENT3

Backward Compatible:

Single event ticker queries continue to work as before
Multiple event tickers return orders from all specified events

Oct 19, 2025

Fixed missing fields in Quote responses: rfq_target_cost_centi_cents, rfq_creator_order_id, and creator_order_id are now properly included in all Quote-related endpoints.

Oct 16, 2025

The GET /events endpoint now supports an optional flag, with_milestones, that includes all milestones related to the returned events.Expected release: October 16, 2025

Oct 14, 2025

The order returned by create order is now the same model as the model returned by get order.

Oct 13, 2025

The GET /v2/incentive_programs and GET /incentive_programs endpoints now return a series_ticker field for each incentive program.Expected release: October 13, 2025

Oct 10, 2025

The price_level_structure field has been moved from the event level to the market level. Each market now has its own price_level_structure field.Affected endpoints:

GET /trade-api/v2/events
GET /trade-api/v2/events/:event_ticker
GET /trade-api/v2/markets
GET /trade-api/v2/markets/:ticker

Note: The price_level_structure field on event objects is now deprecated and will be removed. Please use the field on individual market objects instead.Expected release date: Oct 15th, 2025

Oct 13, 2025

Fixed the GET /series endpoint’s tags parameter to properly support tags containing spaces. Previously, the parameter would split on both commas AND spaces, breaking searches for tags like “Rotten Tomatoes”.Breaking Change:

The tags query parameter now only splits on commas (,), not spaces
Tags with spaces (e.g., “Rotten Tomatoes”) now work correctly
Multiple tags must be comma-separated: ?tags=Rotten Tomatoes,Television

Before (broken):

GET /series?tags=Rotten Tomatoes
// Was incorrectly parsed as: ["Rotten", "Tomatoes"]
// Result: No matches found

After (fixed):

GET /series?tags=Rotten Tomatoes
// Correctly parsed as: ["Rotten Tomatoes"]
// Result: Returns series with the "Rotten Tomatoes" tag

GET /series?tags=Rotten Tomatoes,Television
// Correctly parsed as: ["Rotten Tomatoes", "Television"]
// Result: Returns series with either tag

This change may affect integrations that relied on space-separated tags. Please update to use comma-separated tags only.

Oct 8, 2025

Fixed routing inconsistency where certain collection endpoints required trailing slashes, causing unnecessary 301 redirects for requests without them.Endpoints now returning 200 for requests without trailing slash (previously returned 301):

GET /milestones
GET /structured_targets
GET /multivariate_event_collections
GET /series
GET /api_keys
POST /api_keys

Note: Requests with trailing slashes (e.g., /milestones/) will now receive a 301 redirect to the version without the trailing slash, which is the opposite of the previous behavior.

Oct 9, 2025

Subpenny fields have been added to orders (taker_fees_dollars, maker_fees_dollars), as well as to public trades (yes_price_dollars, no_price_dollars).Endpoints affected:

GET /trade-api/v2/portfolio/orders
GET /trade-api/v2/markets/trades

Oct 9, 2025

Fields have been added to all RFQ and quote messages to support subpenny pricing via the dollar normalized price fields. For more info reference:

Oct 7, 2025

Enhanced the existing GET /portfolio/balance endpoint to include a portfolio_value field that provides the total portfolio value (available balance plus current market value of all positions), both in cents.

Oct 1, 2025

The GET /series/fee_changes endpoint now returns user-facing fee type names (quadratic, quadratic_with_maker_fees, flat) instead of internal fee structure names. This change also applies to CustomerIO notifications for scheduled series fee updates.Expected release: October 1, 2025

Sep 25, 2025

Repeated subscriptions on the same websocket call will no longer error. If passing the same market tickers as before, no action will be taken. If passing new market tickers, they will be added to your existing subscription.Additionally, the user may supply WS Command list_subscriptions to view their existing subscriptions.Expected release: October 1, 2025

Sep 25, 2025

For optimization purposes, partial fills generated by self-crossing FoK orders are not rolled back. If a FoK order self-crosses, order execution proceeds based on self_trade_prevention_type:

taker_at_cross: the taker is canceled, execution stops. Any partial fills are executed.
maker: the maker is canceled, execution continues. After execution, remaining taker quantity is canceled. Any fills are executed.

This fixes a bug where partially filled FoK orders with Maker STP entered into the book after self-crossing. Expected enforced date: Oct 1, 2025.

Sep 22, 2025

User seeking a simple way to determine the direction of their fill should reference purchased_side. Both BUY YES or SELL NO result in purchased_side = YES. The addition of this field is the first step in standardizing the fills websocket and REST endpoints, which have different conventions for the interpretation ‘side’ and ‘user_action’.Expected Enforce Date: deprecation date for existing fields not yet scheduled.

Sep 21, 2025

Added new public API endpoint for getting all of a series’ scheduled fees:

GET /series/fee_changes - Get a series’ fee changes. If query string parameter show_historical is set to true, ALL fee changes previous and upcoming will be shown. If set to false, only upcoming fee changes will be shown

Sep 25, 2025

Specifying order_type is no longer required and only limit type orders will be supported. Price must be supplied based on the underlying market structure. Example usage:

{"yes_price": 99, "side: "yes"} // buy yes or sell no at market price
{"no_price": 99, "side: "no"} // buy no or sell yes at market price

Expected enforce date: Sep 25, 2025

Sep 18, 2025

WebSocket connections per user are limited by usage tier. The default limit begins at 200 and increases based on API usage tier.

Sep 18, 2025

A new WS channel is being introduced for streaming information related to pre-trade communications (RFQs and quotes).

Sep 15, 2025

Additional metadata is being added to RFQs on multivarate events (MVEs) that break down their component parts explicitly. Market payloads are also being expanded with these new optional fields that are filled only for MVE markets.

Sep 15, 2025

Added new public API endpoint for event candlesticks:

GET /candlesticks - Get candlesticks for all markets associated with an event. If the # of candlesticks exceeds 5000, paginate the results and return an adjustedEndTs which should be used as the start_ts for your next request.

Sept 11, 2025

The TypeScript SDK is now available through NPM! Install with npm install kalshi-typescript.Documentation and examples available at docs.kalshi.com

Sep 11, 2025

Added new public API endpoint for forecast percentiles history:

GET /forecast_percentiles_history - Get percentile history of a event forecast

Sep 10, 2025

Added new public API endpoint for incentive programs (not yet live):

GET /incentive_programs - List incentive programs with filtering options (by market ticker, active status, payout status)

Sep 9, 2025

Subpenny pricing fields have been added to websocket messages. Any message bearing price in cents will now also bear an equivalent fixed-point dollars field.For more info, see Subpenny Pricing.

Sep 9, 2025

Both the individual and batch GET events endpoints now also return available_on_brokers which indicates that they are available on intermediate platforms/ brokers.

Sep 6, 2025

The python SDK is being generated from our OpenAPI spec and is available through pip with pip install kalshi-python. Docs for the new SDK are available on docs.kalshi.com/python-sdk.

Aug 31, 2025

Subpenny pricing fields have been added to APIs involving price, fees, and money in general. E.g. next to a field called "price": 12 (representing 12 cents), you will also see "price_dollars": "0.1200", which is a string bearing a fixed-point representation of money accuate to at 4 decimal points.For now, this change is read-only, meaning that the minimum allowable tick size for orders is still 1c. Eventually, we will introduce sub-penny pricing on orders. For now, please prepare for an eventual migration to the higher granularity price representation.For more info, see Subpenny Pricing.

Sep 2, 2025

The market payload has been updated to include two new fields that describe markets which are part of Multivariate Events.

Sep 2, 2025

The market payload has been updated to include two new fields that describe markets which are part of Multivariate Events.

Aug 21, 2025

The MVE payload has been expanded to support more flexible structures. Several fields that are now redundant are deprecated, but not yet removed.

Aug 21, 2025

The Settlements API now includes the settlement value for a yes contract.

Aug 21, 2025

The get_milestones endpoint now uses case-insensitive matching for the category parameter, resolving inconsistent filtering behavior between “Sports” and “sports”.

Aug 14, 2025

Filtering events by close ts and series by tags supported in the API.

Aug 13, 2025

The batch order endpoints are now available to all API users in the demo environment:Affected Endpoints:

POST /portfolio/orders/batched (BatchCreateOrders)
DELETE /portfolio/orders/batched (BatchCancelOrders)

Changes:

Basic tier users can now access batch endpoints in demo environment
Production environment remains unchanged - Advanced tier or higher still required
Rate limits still apply based on user tier

This change enables developers to test batch order functionality without needing Advanced tier access in the demo environment.

Aug 13, 2025

The error messages when an incorrect API signature is passed have been improved

Aug 9, 2025

The OpenAPI specification for the Kalshi API is now available at https://docs.kalshi.com/openapi.yaml. This allows developers to easily generate client libraries and integrate with the API using OpenAPI-compatible tools.

Aug 8, 2025

Added client_order_id field to orderbook delta WebSocket messages. This field appears only when you caused the orderbook change and contains the client_order_id of your order that triggered the delta.WebSocket Message Enhancement:

New field: client_order_id (string, optional)
Present only when the authenticated user’s order causes the orderbook change
Contains the client-provided order ID of the triggering order

See the WebSocket documentation for implementation details.

Aug 1, 2025

Added GET /portfolio/orders/queue_positions endpoint for retrieving queue positions of multiple resting orders.Request Parameters:

market_tickers (optional): Array of market tickers to filter by
event_ticker (optional): Event ticker to filter by

Note: You must specify one of market_tickers and event_ticker in the request.

July 31, 2025

We are migrating our API documentation to a new platform:

RSS feed moved from https://trading-api.readme.io/changelog.rss to https://docs.kalshi.com/changelog/rss.xml
Documentation site trading-api.readme.io is now deprecated
New documentation home: https://docs.kalshi.com
Historical changelog entries will not be backfilled to the new RSS feed

Please update your bookmarks and RSS subscriptions.

July 31, 2025

The GetEventMetadata endpoint has been expanded to include settlement sources.

July 29, 2025

The GetApiVersion endpoint has been removed. API versioning will not be available for the time being.

​Recent Updates

Recent Updates