# gettxoutproof

Returns a hex-encoded proof that “txid” was included in a block.

{% hint style="warning" %}
NOTE: By default this function only works sometimes. This is when there is an unspent output in the utxo for this transaction. To make it always work, you need to maintain a transaction index, using the -txindex command line option or specify the block in which the transaction is included manually (by blockhash).
{% endhint %}

### Argument #1 - txids

**Type:** json array, required

The txids to filter

```
[
  "txid",    (string) A transaction hash
  ...
]
```

### Argument #2 - blockhash

**Type:** string, optional

If specified, looks for txid in the block with this hash

**Result**

| Name | Type   | Description                                                    |
| ---- | ------ | -------------------------------------------------------------- |
| str  | string | A string that is a serialized, hex-encoded data for the proof. |