construction/hash - Cardano

Example code for the construction/hash JSON-RPC method. Complete guide on how to use construction/hash JSON-RPC in GetBlock Web3 documentation.

This endpoint returns the transaction hash of a signed transaction. The hash is the identifier the transaction will have once submitted.

Parameters

The request body is a JSON object with the following fields.

Field	Type	Required	Description
network_identifier	object	Yes	The network to construct for
signed_transaction	string	Yes	The signed transaction CBOR hex

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/construction/hash' \
--header 'Content-Type: application/json' \
--data-raw '{
    "network_identifier": {
        "blockchain": "cardano",
        "network": "mainnet"
    },
    "signed_transaction": "84a400818258200e...signed-cbor..."
}'

JavaScript

example.js

const response = await fetch(
    'https://go.getblock.io/<ACCESS-TOKEN>/construction/hash',
    {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({"network_identifier": {"blockchain": "cardano", "network": "mainnet"}, "signed_transaction": "84a400818258200e...signed-cbor..."})
    }
);
console.log(await response.json());

Python

example.py

import requests

response = requests.post(
    'https://go.getblock.io/<ACCESS-TOKEN>/construction/hash',
    headers={'Content-Type': 'application/json'},
    json={"network_identifier": {"blockchain": "cardano", "network": "mainnet"}, "signed_transaction": "84a400818258200e...signed-cbor..."}
)

print(response.json())

Response

{
    "transaction_identifier": {
        "hash": "10b54fd708ab2e5703979b4ba27ca0339882abc2062e77fbe51e625203a49642"
    }
}

Response Parameters

Field	Type	Description
transaction_identifier	object	The hash the transaction will have once submitted

Use Cases

• Pre-Submit Hashing: Compute the transaction hash before broadcasting

• Tracking Setup: Record the hash to track the transaction later

• Idempotency: Detect a duplicate submission by hash

• Receipts: Return a transaction hash to a user before submission

Error Handling

Error Code	Message	Description
1	Invalid request	A required construction field is missing or malformed
6	Transaction decode failed	The supplied transaction could not be decoded
14	Invalid signature	A supplied signature is malformed or does not match
5	Internal error	The node failed to process the construction step