KALSHI API Docs: a Trader’S Guide to KALSHI API Access
kalshi api docs are the starting point for integrating Kalshi market data and trading workflows into your setup. If you want to pull markets, orderbooks, and fill data or place trades programmatically, these docs describe the REST and WebSocket interfaces you’ll use. This article breaks down the most practical bits of the API, with concrete examples of how to navigate endpoints and authenticate for trading. Expect a focus on the read-only data you’ll monitor alongside the trading actions you’ll execute.
What the kalshi api docs cover for traders
The Kalshi API docs describe the REST trade-api and the WebSocket feed that power programmatic access to markets. You’ll find endpoints for markets, events, series, orderbooks, candlesticks, and trades, plus the authenticated paths for placing and canceling orders and checking balances and fills. The documented base URL for read-only access is the REST surface you’ll use to index liquidity, while the WebSocket stream provides real-time deltas for the order book and trades. Read the docs to understand the expected request shapes, response schemas, and error handling conventions—crucial for building reliable arb logic around recurring events.
Reading market data from the API
Most Kalshi arb work starts with read-only data: markets, events, series, and the orderbook. The API exposes endpoints to list markets and fetch individual market detail, as well as the orderbook snapshot you need to gauge spreads in real time. Candlesticks offer historical OHLC data to backtest your edge. The key is to align the data you pull with Kalshi’s price mechanics—every contract is a YES/NO binary and prices sit within 0.01 to 0.99 dollars, with the sum of YES and NO prices approximating 1.00. Use the min and max timestamps to constrain your queries around the event window you’re watching.
Trading via the API: placing orders securely
Authenticated trading endpoints require an API key and an ECDSA-signed timestamp header. Through POST /portfolio/orders you can place limit or market orders, while DELETE allows canceling. The docs explain how to format orders, handle partial fills, and interpret fills in GET /portfolio/fills. Kalshi’s design means you’ll deal with per-contract fees and a price between 0.01 and 0.99, with the potential to capture edge when the best YES and best NO are priced to sum under 1.00. Security considerations emphasize keeping keys on your side and using the documented authentication flow for any trading activity.
Rate limits, tests, and production readiness
The docs outline rate limits and recommended testing practices to avoid blowing through quotas during high-liquidity events. Use a dry-run or sandbox-like approach if available to verify your logic before trading live. It’s important to validate error handling for common scenarios like self-trade prevention, slippage, and connectivity issues. Production readiness also means respecting market-specific constraints, such as position caps and timing around settlement windows, which the rulebook and API docs help you monitor.
Get started with KalshiArb and Kalshi API docs
Leverage KalshiArb to monitor and trade Kalshi markets using the official Kalshi API docs. Our pricing plans give you scalable alerts and autonomous execution to turn edge into actionable signals.
FAQ
- What is the base URL for read-only Kalshi API data?
- Read-only market data is accessed via the REST API at the base URL https://api.elections.kalshi.com/trade-api/v2. This includes markets, events, series, and orderbook data.
- How do I authenticate for trading via the Kalshi API?
- Trading requires an API key and an ECDSA-signed timestamp header. Use these credentials with the authenticated endpoints to place or cancel orders and view your portfolio.
- What types of data can I fetch with the Kalshi API?
- You can fetch markets, events, series, orderbooks, candlesticks, and trades. There are dedicated endpoints for both read-only data and authenticated trading actions.
- Are there real-time updates available for the order book?
- Yes. The WebSocket feed provides real-time deltas for the order book, trades, and ticker data, complementing the REST read-only endpoints.