BitGo JavaScript SDK

The BitGo SDK is a monorepo composed of several specialized modules. Depending on your use case (UTXO-based coins, account-based coins, or infrastructure), you will need to install and use specific packages.

Key modules include:

• bitgo: Core module for authentication, wallet management, and coin implementations.
• @bitgo/account-lib: For building and signing transactions for account-based coins.
• @bitgo/utxo-lib: For building and signing transactions for UTXO-based coins.
• @bitgo/express: A local BitGo transaction signing server and proxy.
• @bitgo/blockapis: Access to public block explorer APIs.
• @bitgo/statics: Static configuration values used across the platform.

BitGo Express is a local signing server that provides a REST API. It is designed for developers working in languages without an official BitGo SDK.

It runs as a service in your own datacenter and handles client-side operations involving your own keys (such as partially signing transactions) before they are submitted to BitGo. This ensures your private keys never leave your network. Additionally, BitGo Express can proxy standard BitGo REST APIs, providing a unified interface through a single REST API.

The @bitgo/sdk-coin-iota package provides the following capabilities:

• Key pair generation and management
• Address validation
• Transaction building and signing
• TSS (Threshold Signature Scheme) support
• Support for IOTA tokens

The library is organized by coin ticker symbols to separate core logic from blockchain-specific implementations:

• Base Classes: Core interfaces for TransactionBuilder and Transaction are located in src/coin/baseCoin.
• Coin Implementations: The actual signing, validation, and encoding logic for specific blockchains resides in src/coin/<coin-ticker>/ (e.g., src/coin/trx for Tron).
• Tests: Unit tests are located in test, with coin-specific tests organized under test/unit/coin/<coin-ticker>/<coin-ticker>.js.
• External Resources: Small snippets of required upstream code that are not pulled in as full dependencies are stored in resources/.

The Dimensions class is used to calculate an accurate estimate of a transaction's virtual size (vSize), which is critical for determining proper transaction fees. You can instantiate Dimensions using raw attributes or use static factory methods to derive dimensions from unspent outputs, inputs, or outputs.

import { Dimensions } from '@bitgo/unspents';

// Using raw attributes
const dims = new Dimensions({
  nP2shInputs: 1,
  nP2shP2wshInputs: 1,
  nP2wshInputs: 1,
  outputs: { count: 1, size: 32 },
});

// Estimating vSize by combining dimensions
const vSize = Dimensions.fromUnspents({ unspents: myUnspents })
  .plus(Dimensions.fromOutputOnChain(Codes.p2shP2wsh.internal).times(nOutputs))
  .getVSize();