isBlockhashValid

Learn isBlockhashValid use cases, code examples, request parameters, response structure, and tips.

The isBlockhashValid RPC method in CoinVera checks whether a given blockhash is still considered valid by the Solana network. Since blockhashes expire after approximately 150 slots (~1–2 minutes), this method helps ensure that a transaction referencing an older blockhash won't be rejected.

🛈 Version Note: This method is available in Solana v1.9+. For older nodes (v1.8 or earlier), use getFeeCalculatorForBlockhash to implicitly verify blockhash validity.

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✅ Common Use Cases

• Transaction Resubmission Before retrying a failed transaction, check if the original blockhash is still valid.

• Delayed Signing/Submission If a transaction is prepared but submitted later, validate the blockhash to avoid errors.

• Optimistic Transaction Scheduling Ensure a held blockhash is still valid before attempting to send a transaction.

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🧾 Request Parameters

[
  blockhash: string,             // Required – base-58 encoded blockhash string
  options?: {
    commitment?: string,         // Optional – "processed", "confirmed", or "finalized"
    minContextSlot?: number      // Optional – ensure node response is from a recent enough slot
  }
]

• blockhash (required): The blockhash to validate.

• commitment (optional): Query the blockhash validity based on a specific network confirmation level.

• minContextSlot (optional): Ensures the response is based on a slot at least this recent—useful to prevent stale data.

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📦 Response Structure

{
  "context": {
    "slot": 221446650
  },
  "value": true
}

• value: Boolean result — true if the blockhash is valid, false if it has expired.

• context.slot: The slot at which this response was evaluated.

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🧪 Example

Check if a Blockhash is Valid

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "isBlockhashValid",
  "params": [
    "3bXZjQUZw3PyWHVb7fG7Yf6pDD6MiZf9j8nAy4DDWjXu",
    {
      "commitment": "finalized"
    }
  ]
}

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Code Examples

Nodejs

const fetch = require('node-fetch');

async function isBlockhashValid(rpcUrl) {
  try {
    const response = await fetch(rpcUrl, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        jsonrpc: '2.0',
        id: 1,
        method: 'isBlockhashValid',
        "params": [
            "GS2XJrxSKuDa8BLgvGjVTHpsijDkNs53BsJAZLXwgZx1",
            {
              "commitment": "confirmed",
              "minContextSlot": 355397937
            }
          ]
      }),
    });

    const data = await response.json();
    
    // Print the exact full response
    console.log('Full RPC Response:');
    console.log(JSON.stringify(data, null, 2));
    
    return data;
  } catch (error) {
    console.error('Error getting health:', error.message);
    return null;
  }
}

// Example usage
const RPC_URL = 'https://rpc.coinvera.io/?x-api-key=your-coinvera-x-api-key';

isBlockhashValid(RPC_URL);

Python

Example Response

{
  "jsonrpc": "2.0",
  "result": {
    "context": {
      "apiVersion": "2.2.16",
      "slot": 355412699
    },
    "value": false
  },
  "id": 1
}

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💡 Developer Tips

• Blockhash Expiry Blockhashes are valid for ~150 slots. If you’re unsure about age, fetch a fresh one using getLatestBlockhash.

• Use minContextSlot for Accuracy This prevents a stale node from incorrectly reporting a blockhash as valid.

• Legacy Support On nodes running Solana <v1.9, use:

  getFeeCalculatorForBlockhash("<BLOCKHASH>")

  If it fails, the blockhash is no longer valid.

• Validation ≠ Finality A valid blockhash doesn’t guarantee transaction success. Finality is achieved only once the transaction is confirmed at the desired commitment level.

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The isBlockhashValid method is a critical tool in time-sensitive transaction flows, helping developers avoid expired-blockhash errors and ensure smoother interactions on the Solana blockchain using CoinVera.