SDKs & wrappers
Prediction market SDKs and client libraries
Client libraries for the Kalshi and Polymarket APIs, checked for maintenance status, auth support and the breaking changes of 2026.
Checked September 8, 2026 · every price read off the live site
Every sdks & wrappers API
7 reviewed · alphabetical-
@polymarket/client New TypeScript integrations with Polymarket: one typed client for market data, realtime, orders and redemptions, with Viem, Privy and Ethers signers.
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Kalshi official SDKs Spec-faithful Kalshi clients in Python and TypeScript that track the OpenAPI release cadence, when you accept generated code and closed source.
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polymarket-apis (PyPI) Community unified Polymarket library: CLOB, Gamma, Data, Web3, WebSocket and GraphQL in one, Pydantic-validated.
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| API | Venues | Pricing | Type |
|---|---|---|---|
| @polymarket/client | Polymarket | Open source (MIT). | library |
| @polymarket/clob-client-v2 | Polymarket | Open source (MIT). | library |
| Kalshi official SDKs | Kalshi | Free to install. | library |
| kalshi-python-sdk | Kalshi | Open source (MIT). | library |
| polymarket-apis (PyPI) | Polymarket | Free on PyPI. | library |
| Polymarket/py-sdk | Polymarket | Open source (MIT). | library |
| pykalshi | Kalshi | Open source (MIT). | library |
How these APIs work
Client libraries wrap one venue's API in a language you already write. In 2026 both major venues finally have official packages worth using: Polymarket's unified polymarket-client (Python) and @polymarket/client (TypeScript) replaced the archived CLOB clients in July 2026, and Kalshi publishes kalshi_python_sync, kalshi_python_async and kalshi-typescript generated from its OpenAPI spec.
The community packages survive because the official ones leave gaps. Kalshi's SDK page itself warns its packages may lag the API and carry no retry or streaming logic, which is what pykalshi and kalshi-python-sdk add. On the Polymarket side, polymarket-apis reaches the Goldsky subgraphs and gasless Web3 operations the official SDK does not describe.
Pick by language first, then by whether you need WebSockets, retries, Perps or FIX, then by how many people are watching the repo.
How to choose
- Start with the official package for the venue: polymarket-client or @polymarket/client for Polymarket, kalshi_python_sync or kalshi-typescript for Kalshi. Read its own caveats before adding a community layer.
- Check the Python floor. polymarket-client needs 3.11, polymarket-apis and kalshi-sdk need 3.12, Kalshi's official packages need 3.13, pykalshi runs on 3.9.
- If you stream, confirm WebSocket support and a local order book: pykalshi, kalshi-python-sdk and polymarket-apis have both; the official Kalshi packages do not, per pykalshi's comparison table.
- Read the license field, not the badge. polymarket-apis has no LICENSE file; Kalshi's Python packages are LicenseRef-Proprietary.
- Weigh stars and release cadence together. Six stars with 34 releases (kalshi-sdk) and 38 stars with 273 versions (@polymarket/client) both mean fast change; pin versions.
Questions about sdks & wrappers APIs
Is there an official Polymarket Python SDK?
Yes. polymarket-client from the Polymarket/py-sdk repo, first released July 22, 2026 and now at 0.9.0, is the official unified Python SDK. The older py-clob-client is archived.
Does Kalshi have an official SDK?
Yes. kalshi_python_sync, kalshi_python_async and kalshi-typescript, all at 3.29.0. Kalshi recommends generating your own client from the OpenAPI spec for production.
What is the best Kalshi Python library?
pykalshi (123 stars) for notebooks and streaming with pandas; kalshi-python-sdk (pip install kalshi-sdk) for full REST, Perps and FIX coverage; the official kalshi_python_sync for spec parity without extras.
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