Kalshi Python SDK (sync and async)

What it is

Kalshi's current official Python client, and the reason the older kalshi-python card is a dead end. It ships as two packages built from the same specification - kalshi_python_sync and kalshi_python_async - and Kalshi's SDK documentation names both, adds a TypeScript sibling on npm (kalshi-typescript), and says in as many words that the old kalshi-python package is deprecated.

It is generated code, and it does not pretend otherwise: the README inside the wheel is the OpenAPI Generator's template, naming generator version 7.17.0 and API version 3.30.0. The package metadata carries Kalshi's support address as the author email, which is the strongest evidence available that this is the exchange's own publication - the homepage it lists, github.com/Kalshi/exchange-infra, is not readable by the public.

Inside are seventeen API modules covering what the exchange does: markets, events, orders, order groups, portfolio, account, exchange status, historical data, live data, multivariate contracts, milestones, structured targets, search, communications, incentive programs, API keys and FCM. Six runtime dependencies - urllib3, python-dateutil, pydantic, typing-extensions, lazy-imports and cryptography, the last of which does the request signing.

Release cadence is the best thing about it. Thirty-one versions since 3.0.0 on 2025-12-02, the latest 3.30.0 on 2026-09-15, and Kalshi's documentation says releases track the OpenAPI specification and generally go out on a Tuesday or Wednesday, ahead of the corresponding API change. Compare that with the package it replaced, which has not shipped since September 2025.

Availability

The library imposes nothing and installs anywhere pip works - subject to Python 3.13.

The credential does the gating. Authentication is an API key id plus an RSA private key, with RSA-PSS request signing, and the key comes from a funded Kalshi account. Who may open one is a question about the exchange, answered on kalshi; the flags on this card describe the package, which grants no access and blocks none.

Pricing

Free to install, and the exchange does not charge for API access. The licence is not free in the other sense: the published metadata says LicenseRef-Proprietary, so this is a package you may install and use, not one you may fork, vendor or relicense. If you need code you own, Kalshi's own documentation tells you to generate your own client from its specifications.

What a fill costs is Kalshi's fee schedule, which lives on the venue's card.

Markets & resolution

A client resolves nothing. Orders placed through it rest on Kalshi's order book and settle in dollars against the exchange's determination, and the questions reachable through it are whatever Kalshi lists. Prices are in cents over the wire - the generated examples divide balances by 100 - which is the one data-model detail that bites first.

Integrations

REST only. There is no WebSocket client in either package, no CLI and no MCP server; anything live has to be written against Kalshi's separate streaming specification by hand. The TypeScript package kalshi-typescript is the same generated family in another language, published by the same account and at the same version, and its npm metadata carries an OpenAPI Generator default licence rather than a considered one.

For a Python client that does stream, and that you may read, pykalshi is the third-party answer.

Limitations

Python 3.13 or nothing. The requirement is in the package metadata, and it rules out most production images in use today. Nothing on the package page explains why a generated REST client needs the newest interpreter.

No WebSocket. The whole streaming half of the Kalshi API is outside these packages.

No public source repository. The link in the metadata 404s, and the licence is proprietary, so the answer to "what does this do with my key" comes from reading the installed wheel rather than a repository, a changelog or an issue tracker. There is no issue tracker.

Kalshi says it may lag. Its documentation tells active traders to treat the REST OpenAPI and WebSocket AsyncAPI specifications as the source of truth and, for production, to generate their own client or integrate directly. That is unusually honest, and it is also a recommendation not to depend on this package.

Generated ergonomics. Model names track the specification, not the way a trader thinks; there are no domain objects, no local order book, no dataframe helpers and no retry policy of its own.

The documentation host was not reachable from here. The deprecation notice, the RSA-PSS detail and the release cadence above were read in the Internet Archive's capture of Kalshi's SDK overview page dated 2026-07-09, because the live host refused every automated request we made on 2026-09-19. The package facts - versions, dates, dependencies, module list, licence field, Python floor - come from PyPI and from the wheel itself, both read on 2026-09-19.

Alternatives

pykalshi is the maintained third-party client: MIT, WebSocket streaming, a local order book, pandas output, Python 3.9 and up.

ccxt and pmxt reach Kalshi among several venues, if one integration across exchanges matters more than exchange-shaped errors.

kalshi-python is the deprecated package this one replaces, and kalshi-api is the API underneath all of them, which you can call with plain HTTP if a generated client is not worth 3.13.