> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sei.io/llms.txt
> Use this file to discover all available pages before exploring further.

# @sei-js/ledger

> TypeScript library for SEI Ledger app helper functions — address derivation, Amino signing, and CosmJS integration

The `@sei-js/ledger` package provides TypeScript helper functions for the SEI Ledger hardware wallet app. It enables address derivation and offline Amino signing for Cosmos-side transactions on Sei.

<Info>For EVM-side transaction signing with Ethers.js, see the [Ledger Setup (EVM)](/evm/ledger-ethers) guide instead.</Info>

## Installation

```bash theme={"dark"}
npm install @sei-js/ledger
```

## Hardware Requirements

* Ledger Nano S Plus, Nano X, or compatible device
* **SEI app** installed on the Ledger device (via Ledger Live Manager)
* USB or Bluetooth connection to your computer

## Core Functions

### createTransportAndApp

Creates a transport connection and app instance for communicating with the Ledger device.

```typescript theme={"dark"}
import { createTransportAndApp } from '@sei-js/ledger';

const { transport, app } = await createTransportAndApp();
```

**Returns:** `Promise<{ transport: Transport, app: SeiApp }>`

### getAddresses

Retrieves both EVM and Cosmos addresses from the Ledger device for a given derivation path.

```typescript theme={"dark"}
import { createTransportAndApp, getAddresses } from '@sei-js/ledger';

const { app } = await createTransportAndApp();
const { evmAddress, nativeAddress } = await getAddresses(app, "m/44'/60'/0'/0/0");

console.log('EVM address:', evmAddress);
console.log('Sei address:', nativeAddress);
```

**Parameters:**

| Parameter | Type     | Description                                    |
| --------- | -------- | ---------------------------------------------- |
| `app`     | `SeiApp` | Ledger Sei app instance                        |
| `path`    | `string` | HD derivation path (e.g. `"m/44'/60'/0'/0/0"`) |

**Returns:** `Promise<{ evmAddress: string, nativeAddress: string }>`

### SeiLedgerOfflineAminoSigner

A signer class compatible with CosmJS that enables offline Amino signing via Ledger.

```typescript theme={"dark"}
import { SeiLedgerOfflineAminoSigner } from '@sei-js/ledger';

const ledgerSigner = new SeiLedgerOfflineAminoSigner(app, "m/44'/60'/0'/0/0");
```

**Constructor Parameters:**

| Parameter | Type     | Description             |
| --------- | -------- | ----------------------- |
| `app`     | `SeiApp` | Ledger Sei app instance |
| `path`    | `string` | HD derivation path      |

#### getAccounts

Retrieves account information from the Ledger device.

```typescript theme={"dark"}
const accounts = await ledgerSigner.getAccounts();
// [{ address: 'sei1...', pubkey: { type: 'tendermint/PubKeySecp256k1', value: '...' } }]
```

#### signAmino

Signs a transaction document using the Ledger device. The device will prompt for physical confirmation.

```typescript theme={"dark"}
import { StdSignDoc } from '@cosmjs/amino';

const signDoc: StdSignDoc = {
  /* your transaction document */
};
const { signed, signature } = await ledgerSigner.signAmino('sei1...', signDoc);
```

## Complete Example: Delegating Tokens

```typescript theme={"dark"}
import { coins, SigningStargateClient, StdFee } from '@cosmjs/stargate';
import { createTransportAndApp, getAddresses, SeiLedgerOfflineAminoSigner } from '@sei-js/ledger';

async function delegateWithLedger() {
  const rpcUrl = 'https://rpc-testnet.sei-apis.com/';
  const path = "m/44'/60'/0'/0/0";

  const { app } = await createTransportAndApp();
  const { nativeAddress } = await getAddresses(app, path);
  const ledgerSigner = new SeiLedgerOfflineAminoSigner(app, path);

  const client = await SigningStargateClient.connectWithSigner(rpcUrl, ledgerSigner);

  const msgDelegate = {
    typeUrl: '/cosmos.staking.v1beta1.MsgDelegate',
    value: {
      delegatorAddress: nativeAddress,
      validatorAddress: 'seivaloper1...',
      amount: coins(500, 'usei')
    }
  };

  const fee: StdFee = {
    amount: [{ denom: 'usei', amount: '20000' }],
    gas: '200000'
  };

  const result = await client.signAndBroadcast(nativeAddress, [msgDelegate], fee, 'Delegation via Ledger');

  console.log('Broadcast result:', result);
}

delegateWithLedger();
```

## Security

* Ensure your Ledger device is genuine and purchased from official sources
* Always verify transaction details on the Ledger screen before confirming
* Keep your Ledger firmware and the SEI app updated
* Store your recovery phrase securely and never share it