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

# IsBlockhashValid

> Check if a blockhash is still valid on the Solana blockchain using the LaserStream gRPC API.

<hide>
  ## Endpoints

  gRPC services are available on mainnet and devnet with the following URLs:

  * **Mainnet** `https://laserstream-mainnet.helius-rpc.com:443`
  * **Devnet** `https://laserstream-devnet.helius-rpc.com:443`
</hide>

## Authorizations

<ParamField query="x-token" type="string" required>
  Your Helius API key. You can get one for free in the
  [dashboard](https://dashboard.helius.dev/api-keys).
</ParamField>

## Message

<ParamField body="blockhash" type="string" required>
  The blockhash to check as a base-58 encoded string.
</ParamField>

## Response

<ResponseField name="valid" type="boolean">
  Whether the blockhash is still valid (true) or expired (false).
</ResponseField>

<RequestExample>
  ```json Empty Request theme={"system"}
  {}
  ```
</RequestExample>

<ResponseExample>
  ```json theme={"system"}
  {
      "slot": "333440972",
      "valid": false
  }
  ```
</ResponseExample>