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The Delphi Trading SDK (@delphimarkets/sdk) is a TypeScript library that lets you place, query, and cancel orders on six prediction markets through a single unified interface. It wraps the Delphi REST API and adds client-side helpers for the on-chain exchanges that require EIP-712 signed orders.
ExchangeChainWalletSigning
PolymarketPolygonGnosis SafeClient-side EIP-712
Kalshi——Server-side RSA-PSS
Opinion LabsBNB ChainGnosis SafeClient-side EIP-712
Gemini Predictions——Server-side HMAC-SHA512
LimitlessBaseEOAClient-side EIP-712
Predict.funBNB ChainPredict Account / EOAClient-side EIP-712

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Install

npm install @delphimarkets/sdk
Requires Node 18+ (uses native fetch).

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Configure

import { DelphiClient } from '@delphimarkets/sdk';

const client = new DelphiClient({
  apiKey: process.env.DELPHI_API_KEY,        // your_api_key from your Delphi account
  baseUrl: 'https://api.delphiterminal.co',  // production
  timeout: 30_000,                            // optional, default 30s
});
OptionTypeDefaultDescription
apiKeystringrequiredYour Delphi API key. Sent as the X-API-Key header.
baseUrlstringhttp://localhost:8080Use https://api.delphiterminal.co in production.
timeoutnumber30000Request timeout in milliseconds.

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Authentication

Every request to the Delphi API requires the X-API-Key header: 
X-API-Key: your_api_key_here
The SDK adds this automatically based on the apiKey you pass to DelphiClient. Don’t expose your key in client-side code (browser apps) — proxy through your own backend.

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How signing works

This is the most important concept to understand before you write any trading code.
On-chain exchanges require client-side EIP-712 signed orders. Your private key must produce the signature locally and never leave your machine. The Delphi server cannot — and intentionally does not — have access to your private key. If you call POST /api/v1/orders with an unsigned or invalidly-signed payload, the underlying exchange will reject it.This applies to Polymarket, Opinion Labs, Limitless, and Predict.fun.The SDK’s build*Order() helpers do all of this for you — pass in your private key (via a viem WalletClient) and they return a fully-signed payload ready for placeOrder().
For Kalshi and Gemini, the server signs with credentials you registered ahead of time (RSA private key for Kalshi, HMAC secret for Gemini). No client-side cryptography needed.

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Quick example: Polymarket order

import { DelphiClient, buildPolymarketOrder } from '@delphimarkets/sdk';
import { createWalletClient, http } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { polygon } from 'viem/chains';

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

// One-time: derive Polymarket CLOB credentials
await client.derivePolymarketCredentials(process.env.POLYMARKET_PRIVATE_KEY!);

// Per-order: sign locally and place
const account = privateKeyToAccount(`0x${process.env.POLYMARKET_PRIVATE_KEY!}`);
const wallet = createWalletClient({ account, chain: polygon, transport: http() });

const signedOrder = await buildPolymarketOrder(
  {
    tokenId: '12345...',
    side: 'BUY',
    price: 0.55,
    size: '5000000', // 5 USDC, 6 decimals
  },
  wallet,
  true,
);

const order = await client.placeOrder({
  exchange: 'polymarket',
  market_id: 'my-market',
  order_type: 'GTC',
  signed_order: signedOrder,
});

console.log(`Placed: ${order.order_id} (${order.status})`);
For full per-exchange flows, see the per-exchange guides:

Polymarket

EIP-712 signed orders, Gnosis Safe wallet on Polygon

Kalshi

Server-side RSA-PSS signing, US-regulated

Opinion Labs

EIP-712 + Safe on BNB Chain

Gemini Predictions

Server-side HMAC-SHA512 signing

Limitless

EIP-712 signed orders, EOA wallet on Base

Predict.fun

EIP-712 + Kernel smart wallet on BNB Chain

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Order management

The same four methods work for every exchange: 
// Get a single order's status
const status = await client.getOrder(orderId, 'polymarket');

// List all of your tracked orders, optionally filtered by exchange
const all = await client.listOrders();
const polyOnly = await client.listOrders('polymarket');

// Cancel a resting order
await client.cancelOrder(orderId, 'polymarket');
The exchange argument is optional on getOrder and cancelOrder — the server can resolve it from the order store. Passing it explicitly is slightly faster.

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Credentials

For Kalshi, Gemini, Opinion Labs, Limitless, and Predict.fun, register your exchange credentials once, then place orders without further auth setup: 
await client.registerCredentials('kalshi', {
  api_key: process.env.KALSHI_API_KEY_ID!,
  api_secret: kalshiRSAPrivateKeyPEM,
  api_passphrase: '',
});
For Polymarket, use the dedicated derive helper instead — it handles the CLOB HMAC derivation in one call: 
await client.derivePolymarketCredentials(process.env.POLYMARKET_PRIVATE_KEY!);
List which exchanges you’ve connected: 
const { exchanges } = await client.listCredentials();
// e.g. ['kalshi', 'polymarket', 'limitless']

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Error handling

Every API error is wrapped in a DelphiError that exposes the HTTP status code and a server-provided message: 
import { DelphiError } from '@delphimarkets/sdk';

try {
  await client.placeOrder(req);
} catch (err) {
  if (err instanceof DelphiError) {
    console.error(`API error ${err.statusCode}: ${err.message}`);
    // 400 = bad request (malformed signed_order)
    // 401 = auth failed (invalid X-API-Key)
    // 403 = forbidden
    // 502 = upstream exchange returned an error
  }
}
Network and timeout errors surface as standard AbortError / TypeError. The SDK does not auto-retry — that’s intentional, since order placement is non-idempotent.

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TypeScript types

All public types are exported from the package root: 
import type {
  DelphiConfig,
  PlaceOrderRequest,
  PlaceOrderResponse,
  OrderStatusResponse,
  Exchange,
  OrderType,
  OrderSide,
  SignedPolymarketOrder,
  KalshiLimitOrder,
  GeminiPredictionOrder,
  SignedLimitlessOrder,
  PredictFunOrderPayload,
} from '@delphimarkets/sdk';
The package ships ESM, CJS, and .d.ts declarations for full IDE auto-completion.

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Resources

GitHub

Source code, issues, releases

npm

Package page, version history