OpenPX

Unified, open-source prediction market SDK.

One interface to trade across Polymarket and Kalshi. Rust engine with Python & TypeScript SDKs.

   

---

Quick Start

Install

# Rust — add to Cargo.toml
openpx = "0.1"

# Python
pip install openpx

# TypeScript
npm install @openpx/sdk

Fetch Markets

use openpx::ExchangeInner;
use serde_json::json;

#[tokio::main]
async fn main() {
    let exchange = ExchangeInner::new("kalshi", json!({})).unwrap();
    let (markets, _) = exchange.fetch_markets(&Default::default()).await.unwrap();
    for m in &markets[..5] {
        println!("{}: {}", m.id, m.title);
    }
}

from openpx import Exchange

exchange = Exchange("kalshi")
markets = exchange.fetch_markets()
for m in markets:
    print(f"{m.id}: {m.title}")

import { Exchange } from "@openpx/sdk";

const exchange = new Exchange("kalshi", {});
const markets = await exchange.fetchMarkets();
markets.forEach(m => console.log(`${m.id}: ${m.title}`));

# CLI
openpx kalshi fetch-markets --limit 5

Place an Order

let order = exchange.create_order(
    "KXBTC-25MAR14", "Yes", OrderSide::Buy, 0.65, 10.0, HashMap::new(),
).await?;

order = exchange.create_order("KXBTC-25MAR14", outcome="Yes", side="buy", price=0.65, size=10.0)

const order = await exchange.createOrder("KXBTC-25MAR14", "Yes", "buy", 0.65, 10.0);

Unified API

Every exchange exposes the same interface — switch exchanges by changing one string.

Method	Description
fetch_markets	List markets with pagination
fetch_market	Get a single market by ID
fetch_orderbook	L2 orderbook (bids/asks)
fetch_price_history	OHLCV candlestick data
fetch_trades	Recent public trades
create_order	Place a limit order
cancel_order	Cancel an open order
fetch_positions	Current portfolio positions
fetch_balance	Account balance
fetch_fills	Trade execution history
ws orderbook	Real-time orderbook stream
ws activity	Real-time trade & fill stream

Exchange Support

Feature	Polymarket	Kalshi
Markets	✅	✅
Trading	✅	✅
Orderbook	✅	✅
Price History	✅	✅
Trades	✅	✅
Positions	✅	✅
Balance	✅	✅
Fills	✅	✅
WebSocket	✅	✅

Exchange Credentials

Each exchange is optional — only configure what you need.

Exchange	Required Keys	Docs
Polymarket	POLYMARKET_PRIVATE_KEY	docs
Kalshi	KALSHI_API_KEY_ID, KALSHI_PRIVATE_KEY_PEM	docs

Set them as environment variables or in a .env file (auto-loaded by the CLI).

CLI

cargo install --path engine/cli

# Market data (no auth needed)
openpx kalshi fetch-markets
openpx polymarket fetch-market "0x1234..."
openpx kalshi fetch-orderbook KXBTC-25MAR14

# WebSocket streams
openpx kalshi ws-orderbook KXBTC-25MAR14
openpx polymarket ws-activity "0x1234..."

# Sports & crypto (no auth needed)
openpx sports --league nba --live-only
openpx crypto --symbols btcusdt,ethusdt

# Pipe to jq
openpx kalshi fetch-markets --limit 1 | jq '.markets[0].title'

Project Structure

engine/
  core/               Core types, Exchange trait, error handling
  exchanges/          Exchange implementations (kalshi, polymarket)
  sdk/                Unified facade (enum dispatch)
  cli/                CLI tool
  sports/             Sports WebSocket (Polymarket live scores)
  crypto/             Crypto price WebSocket (Binance + Chainlink)
sdks/
  python/             PyO3 bindings + Pydantic models
  typescript/         NAPI-RS bindings + TS types
docs/                 Mintlify documentation site

Development

cargo check --workspace                    # Type check
cargo test --workspace                     # Run tests
cargo clippy --workspace -- -D warnings    # Lint
cargo fmt --all                            # Format
just sync-all                              # Regenerate Python/TS SDKs from Rust types

Star History

Community

• Documentation — Full API reference, guides, and tutorials
• LLM-ready docs — All docs in one copy-pasteable markdown file
• Issues — Bugs & feature requests
• Discussions — Questions & chat

License

MIT