> ## 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.
# Connectivity
> Endpoints, transport configuration, and rate limits for the Kalshi Margin FIX API
## Endpoints
**Order Entry Host:** `margin-mm.fix.elections.kalshi.com`
**Market Data Host:** `margin-marketdata.fix.elections.kalshi.com`
| Purpose | Port | TargetCompID | Description |
| ------------------------------------ | ---- | ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Order Entry (without retransmission) | 8228 | KalshiNR | Submit, modify, and cancel orders; no message persistence or retransmission. Supports [Listener Sessions](/fix-margin/listener-sessions) for read-only streaming |
| Order Entry (with retransmission) | 8230 | KalshiRT | Order entry with message retransmission. Supports [Listener Sessions](/fix-margin/listener-sessions) for read-only streaming. Contact [institutional@kalshi.com](mailto:institutional@kalshi.com) for access |
| Drop Copy | 8229 | KalshiDC | Request-response queries for historical execution reports |
| Market Data | 8233 | KalshiMD | Order book snapshots and incremental updates. Available only on market data host |
**Order Entry Host:** `margin-fix.demo.kalshi.co`
**Market Data Host:** `margin-marketdata.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](/fix-margin/listener-sessions) for read-only streaming |
| Order Entry (with retransmission) | 8230 | KalshiRT | Order entry with message retransmission. Supports [Listener Sessions](/fix-margin/listener-sessions) for read-only streaming. Contact [institutional@kalshi.com](mailto:institutional@kalshi.com) for access |
| Drop Copy | 8229 | KalshiDC | Request-response queries for historical execution reports |
| Market Data | 8233 | KalshiMD | Order book snapshots and incremental updates. Available only on market data host |
## 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`, `KalshiDC`, or `KalshiMD` |
| Session ID | `TargetCompID + SenderCompID` |
Only one FIX connection is allowed per API key. Separate API keys are required for concurrent connections.
## 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](https://docs.aws.amazon.com/elasticloadbalancing/latest/network/create-tls-listener.html#describe-ssl-policies). If your FIX implementation does not support native TLS connections, use a local proxy such as [stunnel](https://www.stunnel.org/).
To obtain the server certificate for pinning on the initiator side:
```bash theme={null}
openssl s_client -showcerts -connect : < /dev/null | openssl x509 > kalshi-fix.pem
```
## Private Connectivity
For participants requiring network-level isolation, Kalshi supports private connectivity via [AWS PrivateLink](https://docs.aws.amazon.com/vpc/latest/privatelink/what-is-privatelink.html). With PrivateLink, FIX traffic is routed entirely within the AWS backbone and never traverses the public internet.
Contact [institutional@kalshi.com](mailto:institutional@kalshi.com) to provision a PrivateLink endpoint for your AWS account.
## Rate Limits
* **Limit**: FIX application messages use the same token model, token costs, and margin Read/Write buckets as the equivalent REST API operations.
* **Scope**: Application messages only (from client to server)
* **Excluded**: Logout (35=5), Heartbeat (35=0), TestRequest (35=1)
* Logon (35=A) **is** rate-limited.
* Order-entry messages use the margin Write bucket. See [Rate Limits and Tiers](/getting_started/rate_limits) for tier budgets and token-cost behavior.
* Mass Cancel Request (35=q) is limited to 1 request/second.
## Maintenance Window
See [Maintenance and Pauses](/getting_started/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](/getting_started/maintenance_and_pauses), 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 |