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Alpha Markets supports two types of orders: limit orders and market orders. This guide shows you how to place both types and manage them effectively.

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Order Types

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Limit Orders

Limit orders sit on the orderbook at your specified price until matched or cancelled. They execute only at your exact price with zero slippage. Best for:
  • Setting precise entry/exit points
  • Making markets (providing liquidity)
  • Trading when you’re not in a hurry

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Market Orders

Market orders execute immediately against the best available prices on the orderbook. They use automatic matching with configurable slippage tolerance. Best for:
  • Entering or exiting positions quickly
  • Trading liquid markets with tight spreads
  • Time-sensitive strategies

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Placing a Limit Order

1

Initialize the client

Set up your AlphaClient with Algod, Indexer, and signer:
import algosdk from 'algosdk';
import { AlphaClient } from '@alpha-arcade/sdk';

const account = algosdk.mnemonicToSecretKey(process.env.MNEMONIC!);
const algodClient = new algosdk.Algodv2('', 'https://mainnet-api.algonode.cloud', 443);
const indexerClient = new algosdk.Indexer('', 'https://mainnet-idx.algonode.cloud', 443);

const client = new AlphaClient({
  algodClient,
  indexerClient,
  signer: algosdk.makeBasicAccountTransactionSigner(account),
  activeAddress: account.addr.toString(),
  matcherAppId: 741347297,
  usdcAssetId: 31566704,
  apiKey: process.env.ALPHA_API_KEY!,
});
2

Fetch a market

Get available markets to trade on:
const markets = await client.getLiveMarkets();
const market = markets[0];
console.log(`Trading on: ${market.title}`);
3

Create the limit order

Place a limit buy order for 1 Yes share at $0.10:
const result = await client.createLimitOrder({
  marketAppId: market.marketAppId,
  position: 1,           // 1 = Yes, 2 = No
  price: 100_000,        // $0.10 (6 decimals)
  quantity: 1_000_000,   // 1 share (6 decimals)
  isBuying: true,        // Buy order
});

console.log(`Order created! Escrow: ${result.escrowAppId}`);
console.log(`Tx IDs: ${result.txIds.join(', ')}`);
All prices and quantities use 6 decimal places. To convert:
  • $0.50 = 500_000
  • 2.5 shares = 2_500_000

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Understanding Positions

  • position: 1 - Yes outcome tokens
  • position: 2 - No outcome tokens

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Understanding Prices

Prices are denominated in USDC with 6 decimals:
Human PriceSDK Value
$0.0110_000
$0.10100_000
$0.50500_000
$1.001_000_000

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Placing a Market Order

Market orders match immediately against the orderbook. They require you to specify a slippage tolerance.
1

Check the orderbook

View available liquidity before placing your order:
const markets = await client.getLiveMarkets();
const market = markets[0];

const book = await client.getOrderbook(market.marketAppId);
console.log(`Yes asks: ${book.yes.asks.length}, Yes bids: ${book.yes.bids.length}`);
2

Find the best price

Sort the orderbook to find the best available price:
if (book.yes.asks.length === 0) {
  throw new Error('No asks available - cannot place market buy order');
}

const bestAsk = book.yes.asks.sort((a, b) => a.price - b.price)[0];
console.log(`Best ask: $${bestAsk.price / 1e6}`);
3

Place the market order

Create the order with slippage protection:
const result = await client.createMarketOrder({
  marketAppId: market.marketAppId,
  position: 1,
  price: bestAsk.price,
  quantity: 1_000_000,   // 1 share
  isBuying: true,
  slippage: 50_000,      // $0.05 max slippage
});

console.log(`Order created! Escrow: ${result.escrowAppId}`);
console.log(`Matched: ${(result.matchedQuantity ?? 0) / 1e6} shares`);
Set slippage based on market depth and urgency:
  • Liquid markets: 20_000 - 50_000 (0.02−0.02 - 0.05)
  • Illiquid markets: 100_000 - 200_000 (0.10−0.10 - 0.20)

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Cancelling Orders

Cancel any unfilled limit order to reclaim your escrowed funds: 
const cancelResult = await client.cancelOrder({
  marketAppId: market.marketAppId,
  escrowAppId: result.escrowAppId,
  orderOwner: account.addr.toString(),
});

console.log(`Cancelled: ${cancelResult.success}`);
You can only cancel orders you own. The orderOwner must match your activeAddress.

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Amending Orders

You can modify an existing order’s price or quantity without cancelling: 
const amendResult = await client.amendOrder({
  marketAppId: market.marketAppId,
  escrowAppId: existingEscrowAppId,
  newPrice: 150_000,      // Update to $0.15
  newQuantity: 2_000_000, // Update to 2 shares (optional)
});

console.log(`Order amended: ${amendResult.success}`);
Amending is cheaper than cancelling + creating a new order, as it reuses the existing escrow app.

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Complete Example: Limit Order

import dotenv from 'dotenv';
import algosdk from 'algosdk';
import { AlphaClient } from '@alpha-arcade/sdk';

dotenv.config();

const main = async () => {
  const account = algosdk.mnemonicToSecretKey(process.env.TEST_MNEMONIC!);
  const algodClient = new algosdk.Algodv2('', 'https://mainnet-api.algonode.cloud', 443);
  const indexerClient = new algosdk.Indexer('', 'https://mainnet-idx.algonode.cloud', 443);

  const client = new AlphaClient({
    algodClient,
    indexerClient,
    signer: algosdk.makeBasicAccountTransactionSigner(account),
    activeAddress: account.addr.toString(),
    matcherAppId: 741347297,
    usdcAssetId: 31566704,
    apiKey: process.env.ALPHA_API_KEY!,
  });

  // Fetch a market
  const markets = await client.getLiveMarkets();
  const market = markets[0];
  console.log(`Placing order on: ${market.title}`);

  // Place a limit buy order: 1 Yes share at $0.10
  const result = await client.createLimitOrder({
    marketAppId: market.marketAppId,
    position: 1,
    price: 100_000,
    quantity: 1_000_000,
    isBuying: true,
  });

  console.log(`Order created! Escrow: ${result.escrowAppId}`);
  console.log(`Tx IDs: ${result.txIds.join(', ')}`);

  // Cancel the order to clean up
  if (result.escrowAppId > 0) {
    const cancelResult = await client.cancelOrder({
      marketAppId: market.marketAppId,
      escrowAppId: result.escrowAppId,
      orderOwner: account.addr.toString(),
    });
    console.log(`Order cancelled: ${cancelResult.success}`);
  }
};

main().catch(console.error);

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Next Steps

Managing Positions

Learn to split, merge, and claim your outcome tokens

Error Handling

Handle common errors and implement retry logic

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