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Executing Swaps

This guide will cover how to execute token swaps on gSwap. We'll show you both exact input swaps (sell a specific amount) and exact output swaps (buy a specific amount).

If you haven't already, please read the Getting Started guide first to install the gSwap SDK.

Prerequisites​

Before executing swaps, you should:

  • Complete the Getting Started guide and have your SDK properly configured.
  • Understand how to get quotes for price estimates
  • Read the Transaction Status Monitoring guide to understand connection management and transaction waiting
  • Have a wallet with sufficient token balance

Setting up the gSwap SDK​

Unlike quoting, which is read-only, swaps require a signer to authenticate transactions. Waiting for your transactions to complete also requires establishing a connection to the event socket.

import { GSwap, FEE_TIER, PrivateKeySigner } from '@gala-chain/gswap-sdk';

// Connect to the event socket (once globally)
await GSwap.events.connectEventSocket();

// Create instance with signer
const signer = new PrivateKeySigner('your-private-key-here');
const gSwap = new GSwap({ signer });

// Define our token pair
const GALA_TOKEN = 'GALA|Unit|none|none';
const USDC_TOKEN = 'GUSDC|Unit|none|none';
const WALLET_ADDRESS = 'eth|123...abc'; // Your wallet address

Exact Input Swaps​

Use exact input swaps when you want to sell a specific amount of input tokens and receive at least a specified minimum amount of output tokens in return:

async function swapExactInput() {
  const pendingTx = await gSwap.swaps.swap(
    GALA_TOKEN, // Token to sell
    USDC_TOKEN, // Token to buy
    FEE_TIER.PERCENT_01_00, // 1% fee tier
    {
      exactIn: '100', // Sell exactly 100 $GALA
      amountOutMinimum: '45', // Accept minimum 45 USDC (slippage protection)
    },
    WALLET_ADDRESS,
  );

  console.log('Swap transaction submitted:', pendingTx.transactionId);

  // Wait for transaction to complete
  const result = await pendingTx.wait();
  console.log('Swap completed successfully!', result);

  return result;
}

Exact Output Swaps​

Use exact output swaps when you want to buy a specific amount of output tokens and are willing to sell up to a specified maximum amount of input tokens:

async function swapExactOutput() {
  const buyAmount = '50'; // Want to buy exactly 50 USDC

  // Execute the swap with slippage protection
  const pendingTx = await gSwap.swaps.swap(
    GALA_TOKEN, // Token to sell
    USDC_TOKEN, // Token to buy
    FEE_TIER.PERCENT_01_00, // 1% fee tier
    {
      exactOut: buyAmount, // Buy exactly 50 USDC
      amountInMaximum: '110', // Maximum 110 $GALA to sell (slippage protection)
    },
    WALLET_ADDRESS,
  );

  console.log('Swap transaction submitted:', pendingTx.transactionId);

  // Wait for transaction to complete
  const result = await pendingTx.wait();
  console.log('Swap completed successfully!', result);

  return result;
}

Tips for Successful Swaps​

Transaction Timing​

  • Get quotes before executing to understand expected amounts (see Quoting guide).
  • Consider the time between quote and execution when setting slippage.
  • Most swaps confirm within 2-3 seconds, but high network activity may sometimes delay transactions.

Slippage Protection​

  • Too tight: Transaction may fail if price moves slightly.
  • Too loose: You may receive less than expected.
  • Recommended: 0.5-1% for stable pairs, 1-3% for volatile pairs.

Gas and Fees​

  • Swaps require gas fees and protocol fees for transaction execution.
  • Fees are automatically deducted from your trade.
  • Factor in costs when evaluating trade profitability.

Next Steps​