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Documentation Index

Fetch the complete documentation index at: https://docs.delphimarkets.com/llms.txt

Use this file to discover all available pages before exploring further.

Kalshi is a CFTC-regulated prediction market exchange. Orders use traditional limit-order semantics with the server signing each request using your registered RSA private key — no client-side cryptography required.

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At a glance

ChainNone (centralized exchange)
Wallet modelNone (USD account balance)
Quote tokenUSD (cents)
SigningServer-side (RSA-PSS)
AuthKalshi API key ID + RSA private key, registered once

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Prerequisites

  • A funded Kalshi account
  • A Kalshi API key pair — generate at kalshi.com/account/api by uploading the public half of an RSA keypair you generate locally
  • Your RSA private key in PEM format
If you don’t already have an RSA keypair, generate one: 
openssl genrsa -out kalshi-key.pem 2048
openssl rsa -in kalshi-key.pem -pubout -out kalshi-key.pub
Upload kalshi-key.pub to Kalshi. Note the API key ID it returns (a UUID).

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One-time setup: register credentials

import { DelphiClient } from '@delphimarkets/sdk';
import { readFileSync } from 'node:fs';

const client = new DelphiClient({
  apiKey: process.env.DELPHI_API_KEY!,
  baseUrl: 'https://api.delphiterminal.co',
});

await client.registerCredentials('kalshi', {
  api_key: process.env.KALSHI_API_KEY_ID!,                       // UUID from Kalshi
  api_secret: readFileSync('./kalshi-key.pem', 'utf-8'),         // RSA PEM, full -----BEGIN... block
  api_passphrase: '',                                             // unused for Kalshi
});
Run this once per user. The Delphi server stores the RSA key encrypted at rest and uses it to sign every Kalshi request you make through the proxy.

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Place an order

const order = await client.placeOrder({
  exchange: 'kalshi',
  market_id: 'KXNHLGAME-26MAR30PITNYI-NYI',
  order_type: 'GTC',
  signed_order: {
    ticker: 'KXNHLGAME-26MAR30PITNYI-NYI',
    side: 'yes',           // 'yes' or 'no' — which Kalshi outcome
    action: 'buy',         // 'buy' or 'sell' (default: 'buy')
    type: 'limit',         // always 'limit' (Kalshi only supports limit orders here)
    price_cents: '54',     // limit price in cents, 1-99
    count: '1',            // number of contracts
  },
});

console.log(`Placed: ${order.order_id} (${order.status})`);

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Order parameters

FieldTypeDescription
tickerstringKalshi market ticker (e.g. KXNHLGAME-26MAR30PITNYI-NYI).
side'yes' | 'no'The outcome you’re trading — Kalshi sides are by outcome, not buy/sell direction.
action'buy' | 'sell'Default 'buy'. To exit a position, use 'sell'.
type'limit'Always 'limit'.
price_centsstringLimit price in cents (1-99). '54' = 54¢ = $0.54.
countstringNumber of contracts.
Kalshi prices are in cents, not dollars or fractions. A 54¢ limit means price_cents: '54', not '0.54'.

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Query and cancel

const status = await client.getOrder(order.order_id, 'kalshi');
const all = await client.listOrders('kalshi');
await client.cancelOrder(order.order_id, 'kalshi');

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Common pitfalls

The server’s signature is being rejected by Kalshi. Usually one of:
  • The PEM you registered isn’t the private half of the keypair you uploaded to Kalshi
  • The PEM has Windows line endings (\r\n) — re-save the file with Unix line endings (\n)
  • The PEM is missing the -----BEGIN PRIVATE KEY----- / -----END PRIVATE KEY----- envelope
Re-register with a fresh PEM read via readFileSync('./kalshi-key.pem', 'utf-8').
Kalshi tickers can change format between events. Pull the latest market list from GET /api/v1/klsi/markets (or the Kalshi API directly) before placing orders to confirm the ticker is current.
Kalshi imposes per-market position limits (often $25,000 max exposure per market for retail accounts). Check your remaining headroom in the Kalshi UI before placing a large order.
Kalshi has separate api.elections.kalshi.com (production) and demo-api.kalshi.co (sandbox) endpoints. The Delphi server uses production by default. Sandbox API keys are not interchangeable. If you want sandbox access for testing, contact Delphi support.

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API reference