---
title: setPrivateKey
description: "Sets the private key on a TronWeb instance for address derivation and signing; since 6.4.0 a leading 0x prefix is stripped."
keywords: ["setprivatekey", "utils", "private key", "signing", "default address", "tronweb"]
---
# setPrivateKey <TitleWithCodeLink2 link="setPrivateKey" />

Set a private key used with the TronWeb instance, used for obtaining the address, signing transactions, and getting balances.

> ❗️WARNING :
>
> Do not use this with any web/user facing TronWeb instances. This will leak the private key.

## Usage

```JavaScript
TronWeb.setPrivateKey(private key);
```

## Parameters

| Parameter   | Description               | Data Type |
| ----------- | ------------------------- | --------- |
| private key | The private key to be set. **Since 6.4.0** a leading `0x` prefix is accepted and stripped before storing. | String    |

## Returns

No return value

## Example

```JavaScript
tronWeb.setPrivateKey('AD71****7509');
tronWeb.defaultPrivateKey
// output-start
'AD71****7509'
// output-end
// Since 6.4.0 a leading `0x` prefix is accepted and stripped before storing
tronWeb.setPrivateKey('0xAD71****7509');
tronWeb.defaultPrivateKey
// output-start
'AD71****7509'
// output-end
```