Kalshi

CFTC-regulated US event-contract exchange. Connect with one line.

Kalshi is the CFTC-regulated US event-contract exchange. Markets are binary (YES / NO) priced 1–99 cents per contract. Authentication is RSA-PSS on every request — your API key id plus a private-key PEM.

Connect

python

import horizon as hz

ex = hz.connect("kalshi",
    demo=True,                                   # demo API for testing
    api_key_id="01234567-89ab-cdef-0123-456789abcdef",
    private_key_pem=open("kalshi_private.pem", "rb").read(),
)
# Market id is the ticker; YES is default, suffix ":NO" for NO side.
ex.buy("INXD-23DEC29-T4500", qty=10, limit=0.55)
print(ex.positions())
ex.close()

Kwargs

Kwarg	Type	Default	Notes
`demo`	`bool`	`False`	Demo API (`demo-api.kalshi.co`) vs. production.
`api_key_id`	`str \\| None`	`None`	Key id from the Kalshi portal. Falls back to `secrets.get("kalshi.api_key_id")`.
`private_key_pem`	`bytes \\| None`	`None`	Inline PEM bytes. Falls back to `secrets.get("kalshi.api_private_key_pem")`.
`http_client`	`HttpClient \\| None`	Rate-limited default	Conservative 10 writes/sec default.
`base_url`	`str \\| None`	Auto	Override when routing through a proxy.
`budget_usd`	`float`	`0.0`	Optional hard cap.

Install

bash

pip install horizon[prediction]
# or
pip install cryptography

Status

Order submit / cancel: shipped.
Balance, positions, open-orders polling: shipped.
WebSocket feed: horizon.data.live.kalshi_ws.
L2 order book reconstruction: follow-up.

Wire format, signature construction, ticker convention: Kalshi (professionals).