Kalshi API v2 Endpoint Reference

Base URLs: which host for which job

The elections hostname is a historical artifact. It serves every category: weather, crypto, economics, sports and politics. Do not read it as election-only.

Market discovery that actually works

The plain /markets listing is a poor discovery tool. Use the events endpoint with nested markets, which returns roughly 250 or more markets across 50 events, and in our testing about 85 percent of those carried real bid depth.

GET https://api.elections.kalshi.com/trade-api/v2/events
    ?status=open
    &with_nested_markets=true
    &limit=50

If you must use /markets, add mve_filter=exclude to strip multivariate events. Expect a narrower and more obscure result set than the events route.

Field renames: v1 to v2

A large share of broken integrations are simply reading v1 field names that no longer exist. Prices moved to dollar strings, sizes moved to fixed point numbers.

All _dollars values are strings. "0.3300" means 33 cents. Cast to float before doing arithmetic, or you will silently concatenate strings.

Authentication: RSA-PSS signing

The signature covers the full path including the /trade-api/v2 prefix. Signing only the short path is the most common auth failure.

# Sign the FULL path, including /trade-api/v2
path_clean = f"/trade-api/v2{endpoint.split('?')[0]}"
message = f"{timestamp_ms}{method}{path_clean}".encode()
signature = private_key.sign(message, PSS(...), SHA256())

Required headers:

• KALSHI-ACCESS-KEY
• KALSHI-ACCESS-TIMESTAMP (milliseconds)
• KALSHI-ACCESS-SIGNATURE

KALSHI-CLIENT-KEY-ID is the old header format and will not authenticate against v2.

Placing orders on v2

The v1 order path returns 410 deprecated_v1_order_endpoint. Use the events order path.

POST https://external-api.kalshi.com/trade-api/v2/portfolio/events/orders

{
  "ticker": "KXBTC15M-26JUL231315-15",
  "side": "bid",
  "count": "1",
  "price": "0.3300",
  "time_in_force": "good_till_canceled",
  "self_trade_prevention_type": "taker_at_cross",
  "client_order_id": "edgeoutcome-1234567890"
}

The response is flat, not wrapped in an order object. Read order_id,status, filled_count and remaining_count at the top level. Cancellation still works via DELETE /portfolio/orders/{order_id}.

GET /portfolio/balance returns {"balance": 1983} in cents, not dollars. There is no available_balance field.

Six mistakes that cost the most time

1. Using external-api.kalshi.com for market data. It returns combo markets with no bids.
2. Signing the path without the /trade-api/v2 prefix. Every authenticated call fails.
3. Calling the retired /portfolio/orders path and getting a 410.
4. Reading available_balance instead of balance, and treating cents as dollars.
5. Expecting integer cents when v2 returns dollar strings such as "0.3300".
6. Unwrapping the order response under an order key that does not exist.

Frequently asked questions

Related guides

• Kalshi API Python Tutorial: authentication, market data and your first order
• Kalshi API v2: what the docs do not tell you about events, fields and orders
• Kalshi data sources: historical prices, order book depth and open interest
• Prediction Market Cheat Sheet: fees, endpoints and resolution rules on one page