Build apps with Bitcoin and Stablecoins on Arkade

Guide for developing with the Arkade TypeScript SDK (@arkade-os/sdk) — Bitcoin wallets, Lightning, smart contracts, and stablecoin swaps.

Arkade SDK Development Guide

Arkade is a programmable Bitcoin execution layer. It uses VTXOs (Virtual Transaction Outputs) to enable instant offchain Bitcoin transactions with near-zero fees, while users retain full self-custody and unilateral exit rights. No changes to Bitcoin are required.

SDK Installation & Setup

npm install @arkade-os/sdk

Requires Node.js >= 22.

import { SingleKey, Wallet } from "@arkade-os/sdk";

// Create an identity (private key)
const identity = SingleKey.fromHex("your-private-key-hex");
// Or generate a new one:
// const identity = SingleKey.fromRandomBytes();

const wallet = await Wallet.create({
  identity,
  arkServerUrl: "https://arkade.computer",
});

const address = await wallet.getAddress();
console.log("Ark Address:", address);

For production, always use a secure key management solution rather than hardcoded keys.

Core Wallet Operations

Addresses

// Offchain Ark address (ark1.../tark1...) — for instant payments
const arkAddress = await wallet.getAddress();

// Boarding address — for receiving onchain BTC to be onboarded later
const boardingAddress = await wallet.getBoardingAddress();

Balances

const balance = await wallet.getBalance();

console.log("Available:", balance.available, "sats"); // spendable now
console.log("Total:", balance.total, "sats"); // includes recoverable
console.log("Settled:", balance.settled, "sats"); // Bitcoin-anchored
console.log("Preconfirmed:", balance.preconfirmed, "sats"); // cosigned

// Pending onchain deposits
console.log("Boarding:", balance.boarding.total, "sats");

Sending Payments

// Send to an Ark address — instant, near-zero fees
const txid = await wallet.sendBitcoin({
  address: "ark1...",
  amount: 50000, // satoshis
});

For onchain destinations (bc1.../tb1...), use the Ramps offboard flow below. For Lightning invoices, use @arkade-os/boltz-swap.

Receiving Payments

const address = await wallet.getAddress();
// Share this address with the sender

// Monitor for incoming funds
const stop = wallet.notifyIncomingFunds(async (notification) => {
  if (notification.type === "vtxo") {
    for (const vtxo of notification.vtxos) {
      console.log(`Received ${vtxo.amount} sats`);
    }
  }
});

// Call stop() when done listening

VTXOs

const vtxos = await wallet.getVtxos();
for (const vtxo of vtxos) {
  console.log(vtxo.txid, vtxo.amount, vtxo.status);
}

Onchain Ramps (Onboard / Offboard)

Convert between onchain Bitcoin UTXOs and offchain Arkade VTXOs. Best for large transfers; for everyday amounts, Lightning swaps have lower overhead.

import { Ramps } from "@arkade-os/sdk";

const ramps = new Ramps(wallet);

// Get fee info from the Ark server
const info = await wallet.arkProvider.getInfo();

// Onboard: convert boarding UTXOs to VTXOs
const commitmentTxid = await ramps.onboard(info.fees);

// Offboard: convert VTXOs to onchain BTC
const exitTxid = await ramps.offboard(
  "bc1q...", // destination onchain address
  info.fees,
  // amount, // optional — defaults to all available
);

Lightning Network

npm install @arkade-os/boltz-swap

Lightning integration uses Boltz submarine swaps to bridge between Arkade and the Lightning Network.

import { ArkadeLightning, BoltzSwapProvider } from "@arkade-os/boltz-swap";

const swapProvider = new BoltzSwapProvider({
  apiUrl: "https://api.ark.boltz.exchange",
  network: "bitcoin",
});

const lightning = new ArkadeLightning({
  wallet,
  swapProvider,
});

// Receive via Lightning (reverse swap)
const { invoice, paymentHash } = await lightning.createLightningInvoice({
  amount: 25000,
});
console.log("Pay this:", invoice);

// Send via Lightning (submarine swap)
const result = await lightning.sendLightningPayment({
  invoice: "lnbc...",
});
console.log("Preimage:", result.preimage);

Boltz API Endpoints

Network	URL
Bitcoin mainnet	https://api.ark.boltz.exchange
Mutinynet	https://api.boltz.mutinynet.arkade.sh
Regtest (local)	http://localhost:9069

Skill Classes (this package)

This package (@arkade-os/skill) provides higher-level wrapper classes over the SDK:

npm install @arkade-os/skill

import { Wallet, SingleKey } from "@arkade-os/sdk";
import {
  ArkadeBitcoinSkill,
  ArkaLightningSkill,
  LendaSwapSkill,
} from "@arkade-os/skill";

const wallet = await Wallet.create({
  identity: SingleKey.fromHex(privateKeyHex),
  arkServerUrl: "https://arkade.computer",
});

// Bitcoin: addresses, balances, send/receive, onboard/offboard
const bitcoin = new ArkadeBitcoinSkill(wallet);
const balance = await bitcoin.getBalance();
await bitcoin.send({ address: "ark1...", amount: 50000 });

// Lightning: invoices, payments via Boltz
const lightning = new ArkaLightningSkill({ wallet, network: "bitcoin" });
const inv = await lightning.createInvoice({ amount: 25000 });

// Stablecoin swaps: BTC <-> USDC/USDT
const lendaswap = new LendaSwapSkill({ wallet });
const quote = await lendaswap.getQuoteBtcToStablecoin(100000, "usdc_pol");

ArkadeBitcoinSkill

• getArkAddress() / getBoardingAddress() — get addresses
• getBalance() — balance breakdown (offchain + onchain)
• send({ address, amount }) — send sats offchain
• getTransactionHistory() — transaction list
• onboard(params) / offboard(params) — onchain ramps
• waitForIncomingFunds(timeout?) — wait for incoming payment

ArkaLightningSkill

• createInvoice({ amount, description? }) — Lightning invoice (reverse swap)
• payInvoice({ bolt11 }) — pay Lightning invoice (submarine swap)
• getFees() / getLimits() — swap fees and limits
• getPendingSwaps() / getSwapHistory() — swap tracking

LendaSwapSkill

• getQuoteBtcToStablecoin(amount, token) / getQuoteStablecoinToBtc(amount, token)
• swapBtcToStablecoin(params) / swapStablecoinToBtc(params)
• getSwapStatus(swapId) / getPendingSwaps() / getSwapHistory()
• claimSwap(swapId) / refundSwap(swapId)
• getAvailablePairs()

Stablecoin Swaps (LendaSwap)

Non-custodial BTC/stablecoin atomic swaps via HTLCs.

Supported tokens: usdc_pol, usdc_eth, usdc_arb, usdt0_pol, usdt_eth, usdt_arb

Supported chains: polygon, ethereum, arbitrum

const lendaswap = new LendaSwapSkill({ wallet });

// Get quote
const quote = await lendaswap.getQuoteBtcToStablecoin(100000, "usdc_pol");
console.log("You'll receive:", quote.targetAmount, "USDC");

// Execute swap (BTC -> USDC)
const swap = await lendaswap.swapBtcToStablecoin({
  targetAddress: "0x...", // EVM address
  targetToken: "usdc_pol",
  targetChain: "polygon",
  sourceAmount: 100000,
});
console.log("Swap ID:", swap.swapId);

// Check status
const status = await lendaswap.getSwapStatus(swap.swapId);

// Claim completed swap
const claim = await lendaswap.claimSwap(swap.swapId);

Smart Contracts

Arkade supports any valid Tapscript as VTXO locking conditions, enabling programmable offchain Bitcoin.

npm install @arkade-os/sdk @scure/base

import {
  RestArkProvider,
  RestIndexerProvider,
  SingleKey,
  VtxoScript,
  MultisigTapscript,
  CSVMultisigTapscript,
} from "@arkade-os/sdk";
import { hex } from "@scure/base";

const arkProvider = new RestArkProvider("https://mutinynet.arkade.sh");
const indexerProvider = new RestIndexerProvider("https://mutinynet.arkade.sh");
const info = await arkProvider.getInfo();
const serverPubkey = hex.decode(info.signerPubkey).slice(1);

Available contract primitives:

• MultisigTapscript — N-of-N multisig
• CLTVMultisigTapscript — Multisig with absolute timelocks
• CSVMultisigTapscript — Multisig with relative timelocks
• VtxoScript — Combine spending paths into Taproot trees

Contract patterns in docs: HTLC/Hashlock, Escrow (3-path), Spilman channels, Dryja-Poon channels, Lightning channels, chain swaps, Oracle DLC.

Use @scure/base for encoding, NOT bitcoinjs-lib.

See: https://docs.arkadeos.com/contracts/overview

Networks & Resources

Network	Server URL	Explorer
Bitcoin mainnet	https://arkade.computer	https://arkade.space
Mutinynet (testnet)	https://mutinynet.arkade.sh	https://explorer.mutinynet.arkade.sh
Signet	https://signet.arkade.sh	https://explorer.signet.arkade.sh
Regtest (local)	http://localhost:7070	—

Local development:

nigiri start --ark

This starts a Bitcoin regtest node with an Arkade operator at http://localhost:7070.

Key Concepts

• VTXOs: Virtual Transaction Outputs — self-custodial offchain Bitcoin coins. States: preconfirmed, settled, recoverable, spent.
• Batch Swaps: How VTXOs achieve Bitcoin finality — multiple transactions batched into a single onchain settlement.
• Preconfirmation: Instant confirmation cosigned by the operator, before onchain settlement.
• Virtual Mempool: DAG-based offchain execution engine that processes Arkade transactions.
• Unilateral Exit: Users can always withdraw their funds onchain without operator cooperation.
• Ark Addresses: ark1... (mainnet) / tark1... (testnet) — bech32m-encoded addresses containing server + user keys.

Documentation

• Full docs: https://docs.arkadeos.com
• Technical primer: https://docs.arkadeos.com/primer
• Wallet SDK v0.3: https://docs.arkadeos.com/wallets/v0.3/setup
• Smart contracts: https://docs.arkadeos.com/contracts/overview
• Lightning swaps: https://docs.arkadeos.com/contracts/lightning-swaps
• LLM-friendly index: https://docs.arkadeos.com/llms.txt
• GitHub: https://github.com/arkade-os/skill