🧪 Code Examples

Ready-to-run TypeScript examples for common Fleet SDK operations

Getting Started

All examples are in the /examples directory and can be run individually:

# Install dependencies
pnpm install

# Run any example
pnpm tsx examples/01-basic-transfer.ts

Example Overview

#	Example	Description	Difficulty
01	Basic Transfer	Send ERG to an address	🟢 Easy
02	Multi-Output	Batch payments to multiple recipients	🟢 Easy
03	Token Transfer	Send native tokens	🟡 Medium
04	NFT Minting	Create EIP-4 NFTs	🟡 Medium
05	Contract Interaction	Compile & use ErgoScript	🟠 Advanced
06	Multi-Sig Wallet	2-of-3 signature scheme	🟠 Advanced
07	Oracle Data	Read on-chain oracle prices	🟠 Advanced
08	DeFi Swap	AMM token swaps	🔴 Expert

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🟢 Basic Examples

01 - Basic Transfer

The simplest transaction: send ERG from one address to another.

Key Concepts:

• TransactionBuilder basics
• Input selection
• Output creation
• Fee handling
• Change address

import { TransactionBuilder, OutputBuilder } from "@fleet-sdk/core";

const tx = new TransactionBuilder(currentHeight)
  .from(inputs)
  .to(new OutputBuilder(1_000_000_000n, recipientAddress))
  .sendChangeTo(senderAddress)
  .payFee(RECOMMENDED_MIN_FEE_VALUE)
  .build();

View Full Example →

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02 - Multi-Output Transaction

Send to multiple recipients in a single transaction.

Key Concepts:

• Multiple OutputBuilders
• Batch processing
• Gas efficiency

const recipients = [
  { address: "addr1...", amount: 1_000_000_000n },
  { address: "addr2...", amount: 2_000_000_000n },
  { address: "addr3...", amount: 500_000_000n }
];

const outputs = recipients.map(r => 
  new OutputBuilder(r.amount, r.address)
);

const tx = new TransactionBuilder(height)
  .from(inputs)
  .to(outputs)
  .sendChangeTo(sender)
  .payFee(fee)
  .build();

View Full Example →

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🟡 Token Examples

03 - Token Transfer

Send native Ergo tokens alongside ERG.

Key Concepts:

• Token handling
• .addTokens() method
• Token change management

const tokenOutput = new OutputBuilder(SAFE_MIN_BOX_VALUE, recipient)
  .addTokens({
    tokenId: "03faf2cb...",
    amount: 100n
  });

View Full Example →

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04 - NFT Minting

Create EIP-4 compliant NFTs with metadata.

Key Concepts:

• EIP-4 standard
• Register encoding (R4-R9)
• NFT artwork types

import { first } from "@fleet-sdk/common";

const nftOutput = new OutputBuilder(SAFE_MIN_BOX_VALUE, minter)
  .mintToken({
    amount: 1n,
    name: "My NFT"
  })
  .setAdditionalRegisters({
    R4: SColl(SByte, utf8.decode("NFT Name")).toHex(),
    R5: SColl(SByte, utf8.decode("Description")).toHex(),
    R6: SColl(SByte, utf8.decode("0")).toHex(),  // Decimals
    R7: SColl(SByte, Buffer.from([1, 2])).toHex(), // Type
    R8: SColl(SByte, utf8.decode("ipfs://...")).toHex()
  });

View Full Example →

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🟠 Advanced Examples

05 - Contract Interaction

Compile ErgoScript and interact with smart contracts.

Key Concepts:

• ErgoScript compilation
• Contract address derivation
• Spending from contracts

import { compile } from "@fleet-sdk/compiler";

const script = `{
  val ownerPk = PK("9f...")
  sigmaProp(HEIGHT > 1500000L && ownerPk)
}`;

const compiled = compile(script);
const contractAddress = compiled.address;

View Full Example →

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06 - Multi-Sig Wallet

Implement 2-of-3 multi-signature wallets.

Key Concepts:

• Multi-sig ErgoScript
• Aggregated signatures
• Team treasury management

const multiSigScript = `{
  val alice = PK("9fAAA...")
  val bob = PK("9fBBB...")
  val charlie = PK("9fCCC...")
  
  sigmaProp(atLeast(2, Coll(alice, bob, charlie)))
}`;

View Full Example →

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07 - Oracle Data Fetch

Read price data from on-chain oracles.

Key Concepts:

• Oracle pool mechanics
• Register decoding
• Price feed integration

// Oracle boxes store price in R4
const priceData = oracleBox.additionalRegisters.R4;
const decodedPrice = decode(priceData);

View Full Example →

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🔴 Expert Examples

08 - DeFi Swap

Interact with AMM DEXes for token swaps.

Key Concepts:

• Constant product formula
• Slippage calculation
• Swap transaction structure

// x * y = k (constant product)
function calculateOutput(
  inputAmount: bigint,
  inputReserve: bigint,
  outputReserve: bigint,
  feePercent: bigint = 3n
): bigint {
  const inputWithFee = inputAmount * (1000n - feePercent);
  const numerator = inputWithFee * outputReserve;
  const denominator = inputReserve * 1000n + inputWithFee;
  return numerator / denominator;
}

View Full Example →

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Running Examples

Prerequisites

# Node.js 18+
node --version

# pnpm (recommended)
npm install -g pnpm

Quick Start

# Clone and install
git clone <repo>
cd fleet-sdk-tutorial
pnpm install

# Run an example
pnpm tsx examples/01-basic-transfer.ts

# Run with watch mode (auto-reload)
pnpm tsx watch examples/01-basic-transfer.ts

Testnet Usage

All examples are configured for testnet. Get testnet ERG from:

• Ergo Testnet Faucet

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Common Issues

Having trouble? Check our Troubleshooting Guide for solutions to common problems.