Skip to main content

​
Introduction

The SubWallet Extension provides a comprehensive JavaScript API that allows decentralized applications (dApps) to interact with user accounts and request transaction signatures. This API is based on the Polkadot.js extension interface with SubWallet-specific enhancements.

​
Package Information

The DApp integration API is provided through the @subwallet/extension-dapp package. 
npm install @subwallet/extension-dapp
or 
yarn add @subwallet/extension-dapp

​
Core Concepts

​
Extension Injection

SubWallet injects itself into the browser’s window.injectedWeb3 object, making it available to all dApps. The extension must be enabled before any other operations can be performed.

​
Account Types

SubWallet supports multiple account types:
  • Substrate accounts: Standard Polkadot/Kusama accounts
  • Ethereum accounts: EVM-compatible accounts
  • Bitcoin accounts: Available through window.SubWalletBitcoin
  • Cardano accounts: Available through window.cardano.subwallet

​
Authentication Options

When enabling the extension, you can specify which account types your dApp requires:
  • substrate: Only Substrate accounts
  • evm: Only EVM accounts
  • both: Both Substrate and EVM accounts

​
Quick Start

Here’s a minimal example to get started: 
import { web3Enable, web3Accounts } from '@subwallet/extension-dapp';

// Enable the extension
const extensions = await web3Enable('My DApp Name');

if (extensions.length === 0) {
  // No extension installed
  console.error('No extension found');
  return;
}

// Get all accounts
const accounts = await web3Accounts();
console.log('Available accounts:', accounts);

​
API Overview

The SubWallet DApp API provides the following main functions:

​
Initialization

  • web3Enable() - Enable extension access for your dApp
  • isWeb3Injected - Check if any extension is injected

​
Account Management

​
Signing Operations

  • Transaction signing via the signer interface
  • Message signing via signRaw()
See the Signing documentation for details.

​
Events & Subscriptions

  • Account change subscriptions
  • Extension initialization events
See the Events documentation for details.

​
TypeScript Support

The package includes full TypeScript definitions. Key types include: 
import type {
  InjectedExtension,
  InjectedAccount,
  InjectedAccountWithMeta,
  Web3AccountsOptions
} from '@subwallet/extension-dapp';

​
Error Handling

All API functions may throw errors. Always wrap calls in try-catch blocks: 
try {
  const accounts = await web3Accounts();
  // Process accounts
} catch (error) {
  console.error('Failed to get accounts:', error.message);
}

​
Common Errors

  • “web3Enable(originName) needs to be called before…” - You must call web3Enable() before using other API functions
  • “Unable to find injected…” - The requested account or extension source was not found
  • “No extension found” - No wallet extension is installed in the browser

​
Browser Compatibility

SubWallet Extension is compatible with:
  • Chrome/Chromium-based browsers
  • Firefox
  • Brave
  • Edge

​
Next Steps

Enable Extension

Learn how to enable SubWallet in your dApp

Manage Accounts

Retrieve and manage user accounts

Sign Transactions

Request transaction signatures from users

Handle Events

Subscribe to account and extension events

Build docs developers (and LLMs) love

Get started for freeTalk to us