Solana: How to perform token swaps using Raydium

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

// Your Chainstack Solana node and wallet
const RPC_ENDPOINT = 'YOUR_CHAINSTACK_SOLANA_NODE'
const PRIVATE_KEY = 'YOUR_PRIVATE_KEY' // base58-encoded

const SWAP_HOST = 'https://transaction-v1.raydium.io'
const BASE_HOST = 'https://api-v3.raydium.io'

const INPUT_MINT = 'So11111111111111111111111111111111111111112'  // SOL
const OUTPUT_MINT = 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v' // USDC
const AMOUNT = 1_000_000   // 0.001 SOL, in lamports
const SLIPPAGE_BPS = 50    // 0.5%
const TX_VERSION = 'V0'

async function swap() {
  const connection = new Connection(RPC_ENDPOINT, 'confirmed')
  const wallet = Keypair.fromSecretKey(bs58.decode(PRIVATE_KEY))

  // 1) Priority fee tiers from Raydium (vh / h / m).
  const { data: fee } = await (await fetch(`${BASE_HOST}/main/auto-fee`)).json()
  const computeUnitPriceMicroLamports = String(fee.default.h) // 'h' = high tier

  // 2) Quote — Raydium routes across its pool types for you.
  const swapResponse = await (
    await fetch(
      `${SWAP_HOST}/compute/swap-base-in?inputMint=${INPUT_MINT}&outputMint=${OUTPUT_MINT}` +
        `&amount=${AMOUNT}&slippageBps=${SLIPPAGE_BPS}&txVersion=${TX_VERSION}`,
    )
  ).json()
  console.log(`Quote: ${AMOUNT} -> ${swapResponse.data.outputAmount} (out)`)

  // 3) Build the swap transaction. wrapSol because the input is native SOL.
  const { data: txs } = await (
    await fetch(`${SWAP_HOST}/transaction/swap-base-in`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        computeUnitPriceMicroLamports,
        swapResponse,
        txVersion: TX_VERSION,
        wallet: wallet.publicKey.toBase58(),
        wrapSol: true,
        unwrapSol: false,
      }),
    })
  ).json()

  // 4) Deserialize, sign, and send each returned transaction through your node.
  for (const { transaction } of txs) {
    const tx = VersionedTransaction.deserialize(Buffer.from(transaction, 'base64'))
    tx.sign([wallet])
    const sig = await connection.sendRawTransaction(tx.serialize(), { skipPreflight: true })
    console.log(`Sent: https://solscan.io/tx/${sig}`)
  }
}

swap()