---
title: updateWitness
description: "Builds an unsigned WitnessUpdateContract transaction that changes the node URL of an existing witness (Super Representative); must be signed and broadcast."
keywords: ["updatewitness", "transactionbuilder", "super representative", "witness url", "update witness", "tronweb"]
---
# updateWitness <TitleWithCodeLink2 link="updateWitness" />

> Added in **6.4.0**.

Create an unsigned `WitnessUpdateContract` transaction that updates the node URL of an
existing witness (Super Representative). The owner account must already be a witness —
see [applyForSR](./applyForSR.md) to register one.

## Usage

```javascript
// Format
const transaction = await tronWeb.transactionBuilder.updateWitness(address, url, options);
```

## Parameters

| Argument | Description | Type |
| -------- | ----------- | ---- |
| address  | The witness owner address (hexstring or base58). Defaults to the instance's `defaultAddress.hex`. | string |
| url      | The new witness node URL. Must be a valid URL and at most 256 characters. | string |
| options  | Optional. See the fields below. | `{ permissionId?: number, blockHeader?: object }` |

- `permissionId` — permission id for multi-signature.
- `blockHeader` — a partial transaction `raw_data` (e.g. `ref_block_bytes`, `ref_block_hash`, `expiration`) that pins the reference block, typically obtained from `await tronWeb.trx.getCurrentRefBlockParams()`.

An invalid or over-long (> 256 chars) URL throws `Invalid url provided`.

## Returns

Unsigned transaction object. It is **not** broadcast — sign and send it with
[`tronWeb.trx.sign`](../trx/sign.md) and
[`tronWeb.trx.sendRawTransaction`](../trx/sendRawTransaction.md) for it to take effect on-chain.

## Example

```javascript
const transaction = await tronWeb.transactionBuilder.updateWitness(
  'TPL66VK2gCXNCD7EJg9pgJRfqcRazjhUZY',
  'https://xtron-updated.network'
);
console.log(transaction);
// output-start
{
  visible: false,
  txID: 'b8d...e0c9',
  raw_data: {
    contract: [
      {
        parameter: {
          value: {
            owner_address: '41928c9af0651632157ef27a2cf17ca72c575a4d21',
            update_url: '68747470733a2f2f7874726f6e2d757064617465642e6e6574776f726b'
          },
          type_url: 'type.googleapis.com/protocol.WitnessUpdateContract'
        },
        type: 'WitnessUpdateContract'
      }
    ],
    ref_block_bytes: '...',
    ref_block_hash: '...',
    expiration: 1718000000000,
    timestamp: 1717999940000
  },
  raw_data_hex: '...'
}
// output-end
```