> ## Documentation Index
> Fetch the complete documentation index at: https://hedera-0c6e0218-mintlify-bc559771.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Get smart contract bytecode

> Fetch the runtime bytecode of any Hedera smart contract with ContractByteCodeQuery, or use the Mirror Node REST API for historical contract data.

A query that returns the bytecode for a smart contract instance. Anyone can request the byte code of a smart contract instance on the network. Queries do not change the state of the smart contract or require network consensus. The information is returned from a single node processing the query.

<Note>
  #### **Recommend Using Mirror Node REST API**

  For obtaining smart contract information and historical data, consider using the Mirror Node REST API endpoint [**Get Contract by ID**](https://docs.hedera.com/api-reference/contracts/get-contract-by-id) which offers several advantages:

  * **Cost-effective and scalable:** [Mirror node providers](/operators/mirror-node#mainnet) offer paid plans with a large number of queries included. The Hedera-hosted mirror node offers free queries with specific throttles for testing. While some SDK queries are currently free, these are subject to change in the future.
  * **Performance:** Mirror nodes don't burden consensus nodes, allowing them to focus on processing transactions and providing efficient access to historical data without impacting network performance.
  * **Historical data:** Mirror nodes store complete transaction history, records, and events - ideal for analytics, auditing, and monitoring past activity.

  📚 ***For more details, please read our [blog post on querying data](https://hedera.com/blog/querying-data-on-hedera-sdk-vs-mirror-node-rest-api).***
</Note>

**Query Signing Requirements**

* The client operator account's private key (fee payer) is required to sign this query

**Query Fees**

* Please see the transaction and query [fees](/learn/networks/mainnet/fees#transaction-and-query-fees) table for the base transaction fee
* Please use the [Hedera fee estimator](https://hedera.com/fees) to estimate your query fee cost

### Methods

| Method                        | Type       | Description                                       | Requirements |
| ----------------------------- | ---------- | ------------------------------------------------- | ------------ |
| `setContractId(<contractId>)` | ContractId | The ID of the contract to return the bytecode for | Required     |

<CodeGroup>
  ```java Java theme={null}
  //Create the query
  ContractByteCodeQuery query = new ContractByteCodeQuery()
      .setContractId(contractId);

  //Sign with the client operator private key and submit to a Hedera network
  ByteString bytecode = query.execute(client);
  ```

  ```javascript JavaScript theme={null}
  //Create the query
  const query = new ContractByteCodeQuery()
      .setContractId(contractId);

  //Sign with the client operator private key and submit to a Hedera network
  const bytecode = await query.execute(client);
  ```

  ```java Go theme={null}
  //Create the query
  query := hedera.NewContractByteCodeQuery().
      SetContractID(contractId)

  //Sign with the client operator private key to pay for the query and submit the query to a Hedera network
  bytecode, err := query.Execute(client)

  if err != nil {
          panic(err)
  }
  ```

  ```rust Rust theme={null}
  // Create the query
  let query = ContractByteCodeQuery::new()
      .contract_id(contract_id);

  // Sign with the client operator private key and submit to a Hedera network
  let bytecode = query.execute(&client).await?;

  println!("Contract bytecode: {:?}", bytecode);

  // v0.34.0
  ```
</CodeGroup>

## Get query values

| Method                        | Type       | Description                            | Requirements |
| ----------------------------- | ---------- | -------------------------------------- | ------------ |
| `getContractId(<contractId>)` | ContractId | Get the contract ID on the transaction | Required     |

<CodeGroup>
  ```java Java theme={null}
  //Create the query
  ContractByteCodeQuery query = new ContractByteCodeQuery()
      .setContractId(newContractId);

  //Get the contract ID
  query.getContractId()

  //v2.0.0
  ```

  ```java JavaScript theme={null}
  //Create the query
  const query = new ContractByteCodeQuery()
      .setContractId(newContractId);

  //Get the contract ID
  query.getContractId()

  //v2.0.0
  ```

  ```java Go theme={null}
  //Create the query
  query := hedera.NewContractByteCodeQuery().
      SetContractID(contractId)

  query.GetContractID()

  //v2.0.0
  ```
</CodeGroup>