Documentation Index
Fetch the complete documentation index at: https://docs.kalshi.com/llms.txt
Use this file to discover all available pages before exploring further.
Endpoints
Host: Provided with your margin FIX credentials| Purpose | Port | TargetCompID | Description |
|---|
| Order Entry (without retransmission) | 8228 | KalshiNR | Submit, modify, and cancel orders; no message persistence or retransmission. Supports Listener Sessions for read-only streaming |
| Order Entry (with retransmission) | 8230 | KalshiRT | Order entry with message retransmission. Supports Listener Sessions for read-only streaming. Contact institutional@kalshi.com for access |
| Drop Copy | 8229 | KalshiDC | Request-response queries for historical execution reports |
Host: margin-fix.demo.kalshi.co| Purpose | Port | TargetCompID | Description |
|---|
| Order Entry (without retransmission) | 8228 | KalshiNR | Submit, modify, and cancel orders; no message persistence or retransmission. Supports Listener Sessions for read-only streaming |
| Order Entry (with retransmission) | 8230 | KalshiRT | Order entry with message retransmission. Supports Listener Sessions for read-only streaming. Contact institutional@kalshi.com for access |
| Drop Copy | 8229 | KalshiDC | Request-response queries for historical execution reports |
Session Configuration
All connections use FIXT.1.1 with application version FIX50SP2.
| Parameter | Value |
|---|
| SenderCompID | Your FIX API key (UUID format) |
| TargetCompID | One of KalshiNR, KalshiRT, or KalshiDC |
| Session ID | TargetCompID + SenderCompID |
SSL/TLS
You must use TLS 1.2 or higher (not plain TCP) to connect to the margin FIX gateway. Cipher suites follow AWS Network Load Balancer TLS policies. If your FIX implementation does not support native TLS connections, use a local proxy such as stunnel.
To obtain the server certificate for pinning on the initiator side:
openssl s_client -showcerts -connect <host>:<port> < /dev/null | openssl x509 > kalshi-fix.pem
Private Connectivity
For participants requiring network-level isolation, Kalshi supports private connectivity via AWS PrivateLink. With PrivateLink, FIX traffic is routed entirely within the AWS backbone and never traverses the public internet.
Contact institutional@kalshi.com to provision a PrivateLink endpoint for your AWS account.
Rate Limits
- Limit: Your account-level rate limits are applicable
- Scope: Application messages only (from client to server)
- Excluded: Logout (35=5), Heartbeat (35=0), TestRequest (35=1)
- Logon (35=A) is rate-limited.
Maintenance Window
See Maintenance and Pauses for scheduled maintenance times and the difference between trading pauses and exchange pauses.
Sessions may be disconnected during the maintenance window. Kalshi does not initiate sequence number resets during maintenance; clients should reset sequence numbers on their side when reconnecting.
KalshiRT sessions retain message continuity across the maintenance window. If your KalshiRT session is disconnected, you can request retransmission of any messages missed during the downtime after reconnecting.
CancelOrderOnPause
To control what happens to your resting orders during a pause, set tag 21006 (CancelOrderOnPause) on your New Order Single (35=D) messages:
| Value | Behavior |
|---|
| Y | Order is automatically cancelled when a trading or exchange pause begins |
| N (default) | Order remains resting on the book and resumes when activity reopens |
