> For the complete documentation index, see [llms.txt](https://docs.baas.sh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.baas.sh/baas-sdk/blockchain/wallet.md).

# Wallet operations

Send transactions, sign messages, and read balances using the wallet the user signed in with. Use these for raw ETH transfers and off-chain signatures. For calls on a contract you've registered with BaaS, see [Smart contracts](/baas-sdk/blockchain/smart-contracts.md).

## Send transactions

`sendTransaction(opts)` submits a transaction to the user's wallet and returns a `BaasTransaction` with the hash and a `wait()` method.

```ts
import { Units } from '@baas/sdk';

// Send native ETH
const tx = await baas.wallet.sendTransaction({
  to:    '0xeoa…',
  value: Units.fromEth(0.001), // 0.001 ETH (or raw wei: '1000000000000000')
});

// Send arbitrary calldata (a custom contract call)
const tx = await baas.wallet.sendTransaction({
  to:    '0xcontract…',
  value: '0',
  data:  '0x12345678…',
});

// External wallet — pass the same provider used at sign-in
const tx = await baas.wallet.sendTransaction({
  to:     '0xeoa…',
  value:  '1000000000000000',
  signer: window.ethereum,
});
```

`value` is denominated in **wei**, the smallest unit of ETH (`1 ETH = 10¹⁸ wei`). `Units.fromEth(0.001)` converts a human amount for you; a raw wei `string` or `bigint` works too. See [Unit conversion](/baas-sdk/blockchain/units.md).

{% hint style="info" %}
When the user signed in with an external wallet, pass the same provider as `{ signer }`. The SDK throws `SIGNER_REQUIRED` otherwise. See [Troubleshooting](/baas-sdk/troubleshooting.md).
{% endhint %}

## Sign messages

`signMessage(message, opts?)` asks the user's wallet to sign an off-chain message and returns a hex signature. Use it to prove the user controls their address, useful for SIWE-like flows or magic-link backends.

```ts
const sig = await baas.wallet.signMessage('Hello, world!');
//  → '0x…' (hex signature)

// With external wallet
const sig = await baas.wallet.signMessage('Hello, world!', {
  signer: window.ethereum,
});
```

As with `sendTransaction`, pass `{ signer }` when the user signed in with an external wallet.

## Read balances

`getBalance(address, opts?)` returns the native balance of an address as a `bigint` (in wei). It's a public read, so no sign-in is required.

```ts
// Default: read from the active chain
const balance = await baas.wallet.getBalance('0xabc…');
console.log(`${Units.toEth(balance)} ETH`); // format the wei bigint for display

// Cross-chain read — for example, read the Mainnet balance from a Sepolia session
const balance = await baas.wallet.getBalance('0xabc…', { chainId: 1 });
```

## Wait for confirmation

`tx.wait(opts?)` polls the chain until the transaction is mined and returns a `TransactionReceipt`.

```ts
const receipt = await tx.wait();
const receipt = await tx.wait({ confirmations: 3 });
const receipt = await tx.wait({ timeout: 60_000 });

console.log(receipt.status); // 'success' | 'reverted'
```

{% hint style="info" %}
**`wait()` polls the chain the transaction was sent on**, not the chain that's active when you call `wait()`. Switching networks between send and wait is safe. The SDK keeps the original polling chain.
{% endhint %}

## Types

```ts
type BaasWallet = {
  sendTransaction(opts: SendTransactionOptions): Promise<BaasTransaction>;
  signMessage(message: string, opts?: SignMessageOptions): Promise<`0x${string}`>;
  getBalance(address: string, opts?: GetBalanceOptions): Promise<bigint>;
};

type BaasTransaction = {
  hash: `0x${string}`;
  wait(opts?: { confirmations?: number; timeout?: number }): Promise<TransactionReceipt>;
};

type SendTransactionOptions = {
  to: string;
  value: string | bigint;
  data?: `0x${string}`;
  chainId?: number;
  signer?: EIP1193Provider;
};
type SignMessageOptions = { signer?: EIP1193Provider };
type GetBalanceOptions  = { chainId?: number };
```

## Next

* [Smart contracts](/baas-sdk/blockchain/smart-contracts.md) — call your registered contracts with the fluent chain.
* [Sessions](/baas-sdk/authentication/sessions.md) — read the session and react to changes.
* [Error handling](/baas-sdk/resources/error-handling.md) — handle `TRANSACTION_REJECTED`, `SIGNER_REQUIRED`, and other wallet errors.


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