Choose Your Stack

Start from who controls the keys and how close you need to be to the protocol.

Browser app using a user's wallet?
  -> @bsv/simple/browser

Backend agent with its own key?
  -> @bsv/simple/server

Coming from another chain and want to build transactions explicitly?
  -> @bsv/wallet-helper

Wallet implementation or wallet infrastructure?
  -> @bsv/wallet-toolbox + BRC-100 spec

Protocol, crypto, scripts, transactions, BEEF, or conformance?
  -> @bsv/sdk

Browser App

Use this when the user already has a local BRC-100 wallet such as BSV Desktop or BSV Browser.

npm install @bsv/simple

import { createWallet } from '@bsv/simple/browser'

const wallet = await createWallet()
const recipientIdentityKey = '025706528f0f6894b2ba505007267ccff1133e004452a1f6b72ac716f246216366'
const result = await wallet.pay({
  to: recipientIdentityKey,
  satoshis: 1000
})

console.log(result.txid)

The web app does not hold private keys. The wallet client finds an available substrate and forwards BRC-100 calls to the user's wallet application.

Transaction Builder

Use @bsv/wallet-helper when you want to construct transactions directly, but you do not want to drop all the way into raw WalletClient.createAction and signAction calls.

This is often the clearest starting point for developers coming from other blockchain stacks: you can think in terms of explicit transaction outputs, scripts, ordinals, metadata, inputs, and change, while the user's BRC-100 wallet still controls keys and signing.

npm install @bsv/wallet-helper

Read this with the BRC-100 method reference when you need to understand what the builder sends to the wallet:

• @bsv/wallet-helper
• createAction
• signAction

Server Agent

Use this for automated services, bots, funding agents, or test harnesses where the service owns a key.

npm install @bsv/simple

import { ServerWallet } from '@bsv/simple/server'

const wallet = await ServerWallet.create({
  privateKey: process.env.SERVER_PRIVATE_KEY!,
  network: 'main',
  storageUrl: 'https://store-us-1.bsvb.tech'
})

Use a secret manager for SERVER_PRIVATE_KEY. Use a region-specific Wallet Infra endpoint when you operate your own deployment.

Wallet Builder

Use @bsv/wallet-toolbox when you are building a BRC-100 wallet, extending wallet storage, implementing permission UX, or porting the model to another language.

npm install @bsv/wallet-toolbox

The toolbox contains the reference pieces: Wallet, WalletStorageManager, storage providers, WalletSigner, Services, Monitor, key managers, permissions, and test utilities such as MockChain.

Read these together:

• @bsv/wallet-toolbox
• BRC-100 Wallet Interface
• Wallet action examples

Protocol Engineer

Use @bsv/sdk for direct access to the core primitives.

npm install @bsv/sdk

The SDK provides secp256k1/r1 cryptography, hashing, scripts, transactions, BEEF (BRC-62), BUMP/Merkle paths (BRC-74), BRC-42 key derivation, ARC broadcasting, Chaintracks clients, BRC-100 interfaces, and wallet substrates.

Service Operator

Use the infrastructure docs when you need shared services rather than npm packages.

Decision Matrix

See Packages for the complete package list.