> ## Documentation Index
> Fetch the complete documentation index at: https://docs.validationcloud.io/llms.txt
> Use this file to discover all available pages before exploring further.

# getblockheader

If verbose is false, returns a string that is serialized, hex-encoded data for blockheader ‘hash’. If verbose is true, returns an Object with information about blockheader ‘hash’.

This method will use `10` [Compute Units](/nodeapi/about/billing).

***

## **Reference:** [**Here**](https://developer.bitcoin.org/reference/rpc/getblockheader.html)

## **Parameters**

**`blockhash`** - string, required

The block hash

**`verbose`** - **boolean, optional, default=true**

true for a json object, false for the hex-encoded data

## Returns (for verbose = true)

```json theme={"theme":{"light":"github-light","dark":"github-dark-default"}}
{                                 (json object)
  "hash" : "hex",                 (string) the block hash (same as provided)
  "confirmations" : n,            (numeric) The number of confirmations, or -1 if the block is not on the main chain
  "height" : n,                   (numeric) The block height or index
  "version" : n,                  (numeric) The block version
  "versionHex" : "hex",           (string) The block version formatted in hexadecimal
  "merkleroot" : "hex",           (string) The merkle root
  "time" : xxx,                   (numeric) The block time expressed in UNIX epoch time
  "mediantime" : xxx,             (numeric) The median block time expressed in UNIX epoch time
  "nonce" : n,                    (numeric) The nonce
  "bits" : "hex",                 (string) The bits
  "difficulty" : n,               (numeric) The difficulty
  "chainwork" : "hex",            (string) Expected number of hashes required to produce the current chain
  "nTx" : n,                      (numeric) The number of transactions in the block
  "previousblockhash" : "hex",    (string) The hash of the previous block
  "nextblockhash" : "hex"         (string) The hash of the next block
}
```

## Returns (for verbose = false)

| Name | Type | Description |
| - | - | - |
| hex | string | A string that is serialized, hex-encoded data for block ‘hash’ |

<CodeGroup>
  ```bash title="mainnet" theme={"theme":{"light":"github-light","dark":"github-dark-default"}}
  curl https://mainnet.bitcoin.validationcloud.io/v1/<YOUR_API_KEY_HERE> \
   -X POST \
   -H "Content-Type: application/json" \
   -d '{
  	"jsonrpc": "1.0",
  	"id": "curltest",
  	"method": "getblockheader",
  	"params": ["00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"]
  }'
  ```

  ```bash title="testnet" theme={"theme":{"light":"github-light","dark":"github-dark-default"}}
  curl https://testnet.bitcoin.validationcloud.io/v1/<YOUR_API_KEY_HERE> \
   -X POST \
   -H "Content-Type: application/json" \
   -d '{
  	"jsonrpc": "1.0",
  	"id": "curltest",
  	"method": "getblockheader",
  	"params": ["00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"]
  }'
  ```
</CodeGroup>


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