How to Swap Tokens on Solana

import { VersionedTransaction, Keypair } from '@solana/web3.js';
import bs58 from 'bs58';

const API_KEY = 'YOUR_API_KEY';
const wallet = Keypair.fromSecretKey(bs58.decode(process.env.PRIVATE_KEY));

// 1. Get order
const orderResponse = await (
  await fetch(
    'https://api.jup.ag/ultra/v1/order?' +
      'inputMint=So11111111111111111111111111111111111111112' +
      '&outputMint=EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v' +
      '&amount=1000000000' +
      `&taker=${wallet.publicKey.toBase58()}`,
    { headers: { 'x-api-key': API_KEY } }
  )
).json();

if (!orderResponse.transaction) {
  throw new Error(orderResponse.errorMessage || orderResponse.error || 'No transaction returned');
}

console.log(`Quote: ${orderResponse.inAmount} → ${orderResponse.outAmount}`);
console.log(`Router: ${orderResponse.router} | Gasless: ${orderResponse.gasless} | Fee: ${orderResponse.feeBps} bps`);

// 2. Sign
const transaction = VersionedTransaction.deserialize(
  Buffer.from(orderResponse.transaction, 'base64')
);
transaction.sign([wallet]);
const signedTransaction = Buffer.from(transaction.serialize()).toString('base64');

// 3. Execute
const executeResponse = await (
  await fetch('https://api.jup.ag/ultra/v1/execute', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': API_KEY,
    },
    body: JSON.stringify({
      signedTransaction,
      requestId: orderResponse.requestId,
    }),
  })
).json();

if (executeResponse.status === 'Success') {
  console.log(`Done: https://solscan.io/tx/${executeResponse.signature}`);
  console.log(`In: ${executeResponse.inputAmountResult} | Out: ${executeResponse.outputAmountResult}`);
} else {
  console.error(`Failed (${executeResponse.code}): ${executeResponse.error}`);
}

interface OrderResponse {
  mode: string;
  inputMint: string;
  outputMint: string;
  inAmount: string;                // Input amount in native units
  outAmount: string;               // Expected output in native units
  otherAmountThreshold: string;    // Minimum output after slippage
  swapMode: string;                // "ExactIn"
  slippageBps: number;             // Set automatically by RTSE
  routePlan: RoutePlan[];
  router: 'iris' | 'jupiterz' | 'dflow' | 'okx';
  transaction: string | null;      // Base64 unsigned tx (null if no taker)
  requestId: string;               // Pass to /execute
  gasless: boolean;
  feeBps: number;                  // Total fee in bps
  feeMint: string;                 // Token mint fees are collected in
  inUsdValue: number;
  outUsdValue: number;
  priceImpact: number;
  signatureFeeLamports: number;
  prioritizationFeeLamports: number;
  rentFeeLamports: number;
  totalTime: number;               // API response time in ms
  // JupiterZ only
  quoteId?: string;
  maker?: string;
  expireAt?: string;
  // Present when simulation fails but quote exists
  errorCode?: number;
  errorMessage?: string;
}

interface RoutePlan {
  swapInfo: {
    ammKey: string;
    label: string;       // e.g. "MeteoraDLMM", "JupiterZ", "Raydium"
    inputMint: string;
    outputMint: string;
    inAmount: string;
    outAmount: string;
  };
  percent: number;       // Route split percentage
  bps: number;           // Route split in basis points
}

interface ExecuteResponse {
  status: 'Success' | 'Failed';
  signature: string;
  slot: string;
  code: number;                    // 0 = success, negative = error
  error?: string;
  inputAmountResult?: string;      // Actual input consumed
  outputAmountResult?: string;     // Actual output received
  swapEvents?: SwapEvent[];        // Breakdown of individual swaps in the route
}

interface SwapEvent {
  inputMint: string;
  inputAmount: string;
  outputMint: string;
  outputAmount: string;
}