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Overview

In order to scale capacity, Kalshi will be splitting trading across multiple matching engines. Exchange instances will correspond to a specific category (e.g. “crypto” exchange, a “combos” exchange). Kalshi plans to add shards incrementally to maintain a healthy balance of traffic.

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Timeline

Initially, Kalshi will migrate combos from the “default” exchange instance to shard 1.
  • August 6, 2026: intra-exchange instance transfers enabled to exchange index 1.
  • August 10, 2026: KXMVECROSSCATEGORY-SHARD1-R multivariate event collection created with support for all combos.
  • August 17, 2026: combos created over legacy collections KXMVESPORTSMULTIGAMEEXTENDED-R, KXMVECROSSCATEGORY-R will be created on shard 1.
  • August 24, 2026: support for KXMVESPORTSMULTIGAMEEXTENDED-R, KXMVECROSSCATEGORY-R is dropped.

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Balance Management

Kalshi’s collateralization checks will continue to run within the matching engine. Programmatic traders must preallocate collateral on a given exchange shard before order placement. API changes:
  • POST /portfolio/intra_exchange_instance_transfer: Given a source and destination exchange index, Kalshi will transfer funds for the user without clearing delay.
  • GET /portfolio/balance: Kalshi provides a breakdown of account balance per exchange instance.

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Order routing

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Market Data

exchange_index is provided on GET /markets, GET /events, and via the WebSocket stream for newly created events and markets.

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REST

The exchange_index parameter is available on a per-endpoint basis.
  • If omitted: defaults to 0.
  • Else if -1: routes to the target exchange for the provided market ticker.
  • Else if >= 0: routes directly to the target exchange.

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FIX

The ExDestination parameter (FIX Tag 100) is available on a per-message basis.
  • If omitted: defaults to 0.
  • Else if -1: routes to the target exchange for the provided Symbol (FIX Tag 55).
  • Else if >= 0: routes directly to the target exchange.

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FAQ

  • All child markets of an event will live on the same exchange instance.
  • Providing ExDestination / exchange_index is unnecessary for combo requests, which are routed internally by Kalshi.
  • Automatic routing will incur an additional latency cost.
  • Subaccount balances are local to a specific exchange instance.
  • Order groups do not function across exchange instances.
  • KXMVECROSSCATEGORY-SHARD1-R is live in demo for testing.