Tooling
Rest API
A REST API is Kalshi’s read/write interface for markets, events, and trades via HTTP endpoints.
Detailed explanation
The REST API is Kalshi’s programmable interface for interacting with markets, events, and your account. Read-only data (markets, events, order books, and candlesticks) can be fetched without an API key, while trading requires an API key and an ECDSA-signed timestamp header. Use the trade API base URL to pull market data or place and cancel orders, and rely on standard REST methods (GET for data, POST/DELETE for actions). Kalshi emphasizes that all access is over USD settlements and that authentication controls trading actions.
Worked example
To observe current pricing, a trader might GET https://api.elections.kalshi.com/trade-api/v2/markets and see a market showing YES at 42¢ and NO at 56¢ (sum 98¢), yielding a 2¢ edge if you buy both sides. If you decide to place a trade, you’d POST to /portfolio/orders with your API key and a signed timestamp to buy YES at 42¢ and NO at 56¢ (both contracts), respecting per-contract fee rules.
FAQ
- What data can I access without authentication?
- All read-only data such as markets, events, series, and order books can be retrieved without an API key. Trading actions require authentication.
- How do I place trades via the REST API?
- Authenticate with an API key and ECDSA-signed timestamp, then use POST /portfolio/orders to submit buy/sell orders for YES/NO contracts.
- Are there rate limits?
- Yes. The API enforces rate limits to protect the service; see the live docs for exact thresholds per endpoint.
See Rest API on a live Kalshi market
KalshiArb scans every open Kalshi market for arbitrage edges where YES + NO < $1.00. Plug in your Kalshi API key and start receiving alerts in under 5 minutes.