---
id: tx-client
sidebar_position: 1
title: 'Tx Client'
---

## About Tx

A transaction contains at least:

1. construct a transaction: The sdk already provides each transaction type
2. simulate: [txClient.simulate](#simulate)
3. broadcast [txClient.broadcast](#broadcast)

## simulate

Just Simulate a transaction and valid transaction.

| params | description                          |
| ------ | ------------------------------------ |
| denom  | the coin denom to query balances for |

```jsx title="simulate tx"
// `tx` is a transaction constructed by the sdk
const simulateInfo = await tx.simulate({
  denom: 'BNB',
});
```

## broadcast

Broadcast the transaction to the chain.

| params                | description                                                                                                       |
| --------------------- | ----------------------------------------------------------------------------------------------------------------- |
| denom                 | the coin denom to query balances for                                                                              |
| gasLimit              | can be set to any number, but not too small or the transaction may fail (recommended use `simulateInfo.gasLimit`) |
| gasPrice              | 1 unit of Gas that the transaction sender is willing to pay.                                                      |
| payer                 | transaction sender                                                                                                |
| granter               | transaction ganter (Generally empty `''`)                                                                         |
| signTypedDataCallback | broadcast use `window.ethereum` as signature provider by default.                                                 |
| privateKey            | If you broadcast in Nodejs, you can broadcast a tx by privateKey                                                  |

```jsx title="broadcast tx"
// broadcast tx
const broadcastRes = await transferTx.broadcast({
  denom: 'BNB',
  gasLimit: Number(simulateInfo.gasLimit),
  gasPrice: simulateInfo.gasPrice,
  payer: '0x0000000000000000000000000000000000000001',
  granter: '',
});
```

:::tip

If you want to use others wallet, you can set `signTypedDataCallback`:

```jsx
// trustwallet:
const broadcastRes = await transferTx.broadcast({
  // ...
  signTypedDataCallback: async (addr: string, message: string) => {
    return await window.trustwallet.request({
      method: 'eth_signTypedData_v4',
      params: [addr, message],
    });
  },
});
```

If you broadcast in Nodejs, you can broadcast a tx by privateKey:

```jsx
const broadcastRes = await transferTx.broadcast({
  // ...
  privateKey: '0x.......',
});
```

:::

## Example

Take `transfer` tx as an example.

### 1. construct a transaction

```jsx title="construct tx"
const transferTx = await client.account.transfer({
  fromAddress: address,
  toAddress: transferInfo.to,
  amount: [
    {
      denom: 'BNB',
      amount: '1000000000',
    },
  ],
});
```

### 2. simulate

```jsx title="simulate tx"
const simulateInfo = await transferTx.simulate({
  denom: 'BNB',
});
```

### 3. broadcast

```jsx title="broadcast tx"
const broadcastRes = await transferTx.broadcast({
  denom: 'BNB',
  gasLimit: Number(simulateInfo.gasLimit),
  gasPrice: simulateInfo.gasPrice,
  payer: address,
  granter: '',
});
```