gettxoutproof

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

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).

This method will use 10 Compute Units.

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Reference: Here

Parameters

txids - json array, required

The txids to filter

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

blockhash - string, optional

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

Returns

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