What is the output from a transaction when burning tokens?

Question

I'm submitting a transaction to burn token to the blockfrost API and receives the following error

(ApplyTxError 
    [UtxowFailure 
        (WrappedShelleyEraFailure 
            (UtxoFailure 
                (ValueNotConservedUTxO 
                    (Value 871447193 
                        (fromList   
                            [(PolicyID {policyID = ScriptHash \"425754c55895d05430ea30c57a6bc2f7f180756f598a5bb0221c3357\"}
                             ,fromList [(\"LoyaltyCoin\",-55)]
                             )
                            ,(PolicyID {policyID = ScriptHash \"bd7f7e20e9d43ffb11fdd3c08f32fc31292f8deb72696e5fe003c832\"}
                             ,fromList [(\"FrankCoin\",3000),(\"SyncroCoin\",1000)]
                             )
                            ])) 
                    (Value 871447193 
                        (fromList   
                            [(PolicyID {policyID = ScriptHash \"bd7f7e20e9d43ffb11fdd3c08f32fc31292f8deb72696e5fe003c832\"}
                             ,fromList [(\"FrankCoin\",3000),(\"SyncroCoin\",1000)]
                             )
                            ]
                        ))
                )
            )
        )
    ]
)

How should a transaction that burns tokens look like?

Answer 1

I don’t know blockfrost but I know that a Cardano-transaction has a special field for minting. You should pass a Value to this field with a negative integer for the tokens you want to burn. Additionally you need to add the currency policy script to the transaction.

A transaction would have as inputs for instance a UTxO with 2 Ada and 55 xyz-tokens. The output would be a UTxO with just 2 Ada. The minting field would be a value with -55 xyz-tokens.

I hope this helps a bit.

Answer 2

Your problem is ValueNotConservedUTxO because your inputs and outputs values not conserved as (Input UTXO ≠ Fee + Amount sent + Change).