Skip to content

02-buy-tokens.md

Latest commit

 

History

History
197 lines (148 loc) · 5.82 KB

02-buy-tokens.md

File metadata and controls

197 lines (148 loc) · 5.82 KB

Tutorial 2: Buy Tokens from the Bonding Curve

Purchase tokens using SOL through the Pump bonding curve.

Prerequisites

  • Completed Tutorial 1 or have a known token mint address
  • A funded Solana wallet
npm install @nirholas/pump-sdk @solana/web3.js bn.js

How Buying Works

When you buy tokens on Pump, the bonding curve determines the price:

Price = virtualSolReserves / virtualTokenReserves

As more tokens are bought, the price increases along the curve. The SDK handles all the math for you.

Step 1: Fetch the Current State

Before buying, you need the current bonding curve state:

import { Connection, Keypair, PublicKey } from "@solana/web3.js";
import { OnlinePumpSdk, PUMP_SDK, getBuyTokenAmountFromSolAmount } from "@nirholas/pump-sdk";
import BN from "bn.js";

const connection = new Connection("https://api.devnet.solana.com", "confirmed");
const onlineSdk = new OnlinePumpSdk(connection);

const mint = new PublicKey("YOUR_TOKEN_MINT_ADDRESS");
const buyer = Keypair.generate(); // Use your funded keypair

// Fetch all state needed for buying
const buyState = await onlineSdk.fetchBuyState(mint, buyer.publicKey);

Step 2: Calculate How Many Tokens You'll Get

Use the bonding curve math to preview your purchase:

const solToSpend = new BN(100_000_000); // 0.1 SOL (in lamports)

// Fetch global + feeConfig alongside buyState for the math
const [global, feeConfig] = await Promise.all([
  onlineSdk.fetchGlobal(),
  onlineSdk.fetchFeeConfig(),
]);

const tokensYouGet = getBuyTokenAmountFromSolAmount({
  global,
  feeConfig,
  mintSupply: buyState.bondingCurve.tokenTotalSupply,
  bondingCurve: buyState.bondingCurve,
  amount: solToSpend,
});

console.log("Tokens you'll receive:", tokensYouGet.toString());

Step 3: Build the Buy Instructions

OnlinePumpSdk.buyInstructions() fetches global internally, so you only need to spread the buyState:

const buyIxs = await onlineSdk.buyInstructions({
  ...buyState,
  mint,
  user: buyer.publicKey,
  amount: tokensYouGet,  // Min tokens you want
  solAmount: solToSpend, // SOL you're spending
  slippage: 0.05,        // 5% slippage tolerance
});

Understanding the Parameters

  • amount — The minimum number of tokens you want to receive
  • solAmount — The SOL amount you're willing to spend
  • slippage — Acceptable price deviation (0.05 = 5%)
  • The SDK automatically creates associated token accounts if needed

Step 4: Send the Transaction

import { TransactionMessage, VersionedTransaction } from "@solana/web3.js";

const { blockhash } = await connection.getLatestBlockhash("confirmed");

const message = new TransactionMessage({
  payerKey: buyer.publicKey,
  recentBlockhash: blockhash,
  instructions: buyIxs,
}).compileToV0Message();

const tx = new VersionedTransaction(message);
tx.sign([buyer]);

const signature = await connection.sendTransaction(tx);
console.log("Buy successful! Tx:", signature);

Full Example

import { Connection, Keypair, PublicKey, TransactionMessage, VersionedTransaction } from "@solana/web3.js";
import { OnlinePumpSdk, getBuyTokenAmountFromSolAmount } from "@nirholas/pump-sdk";
import BN from "bn.js";

async function buyTokens() {
  const connection = new Connection("https://api.devnet.solana.com", "confirmed");
  const onlineSdk = new OnlinePumpSdk(connection);
  const buyer = Keypair.generate(); // Use your funded keypair
  const mint = new PublicKey("YOUR_TOKEN_MINT_ADDRESS");

  // Fetch state in parallel
  const [buyState, global, feeConfig] = await Promise.all([
    onlineSdk.fetchBuyState(mint, buyer.publicKey),
    onlineSdk.fetchGlobal(),
    onlineSdk.fetchFeeConfig(),
  ]);

  // Calculate tokens
  const solToSpend = new BN(100_000_000); // 0.1 SOL
  const tokensOut = getBuyTokenAmountFromSolAmount({
    global,
    feeConfig,
    mintSupply: buyState.bondingCurve.tokenTotalSupply,
    bondingCurve: buyState.bondingCurve,
    amount: solToSpend,
  });
  console.log(`Spending 0.1 SOL → ${tokensOut.toString()} tokens`);

  // Build buy instructions (fetches global internally)
  const buyIxs = await onlineSdk.buyInstructions({
    ...buyState,
    mint,
    user: buyer.publicKey,
    amount: tokensOut,
    solAmount: solToSpend,
    slippage: 0.05,
  });

  // Send
  const { blockhash } = await connection.getLatestBlockhash("confirmed");
  const message = new TransactionMessage({
    payerKey: buyer.publicKey,
    recentBlockhash: blockhash,
    instructions: buyIxs,
  }).compileToV0Message();

  const tx = new VersionedTransaction(message);
  tx.sign([buyer]);
  const sig = await connection.sendTransaction(tx);
  console.log("Bought tokens!", sig);
}

buyTokens();

Understanding Fees

Every buy incurs fees that are split between:

  • Protocol fees — go to Pump
  • Creator fees — go to the token creator

The fee tier depends on the bonding curve's market cap. See Tutorial 9: Understanding the Fee System.

Common Errors

Error Cause Fix
Bonding curve complete Token graduated to AMM Use AMM buy instructions — see Tutorial 24
Insufficient SOL Wallet doesn't have enough SOL for trade + fees + rent Fund the wallet with more SOL
Slippage exceeded Price moved between quote and execution Increase slippage tolerance or retry
0 tokens output SOL amount too small after fees Increase solToSpend amount 
// Always check if the curve is still active before buying
const bc = await onlineSdk.fetchBondingCurve(mint);
if (bc.complete) {
  console.log("Token graduated — use AMM instructions instead");
  return;
}

What's Next?