Create a smart contract

A transaction that creates a new smart contract instance. After the contract is created you can get the new contract ID by requesting the receipt of the transaction. To create the solidity smart contract, you can use remix or another Solidity compiler. After you have the hex-encoded bytecode of the smart contract you need to store that on a file using the Hedera File Service. Then you will create the smart contract instance that will run the bytecode stored in the Hedera file, referenced by file ID. Alternatively, you can use the ContractCreateFlow() API to create the file storing the bytecode and contract in a single step.

The constructor will be executed using the given amount of gas, and any unspent gas will be refunded to the paying account. Constructor inputs are passed in the constructorParameters.

If this constructor stores information, it is charged gas to store it. There is a fee in hbars to maintain that storage until the expiration time, and that fee is added as part of the transaction fee.

Solidity Support

The latest version of Solidity is supported on all networks (v0.8.9).

Smart Contract State Size and Gas Limits

The max contract key value pairs are 16,384,000 (~100 MB). The system gas throttle is 15 million gas per second. Contract call and contract create are throttled at 8 million gas per second.

Admin Key Support for Contracts

With HIP-904, contracts now support Admin Key settings. Set an Admin Key during the ContractCreate transaction to manage and update token properties. For frictionless-airdrop enabled contracts, set maxAutoAssociations during the ContractCreate transaction, ensuring that balance and associations can be managed with a valid Admin Key.

Transaction Signing Requirements

• The client operator account is required to sign the transaction.
• The admin key, if specified.
• The key of the autorenewal account, if specified.

Transaction Fees

• Please see the transaction and query fees table for the base transaction fee.
• Please use the Hedera fee estimator to estimate the cost of your transaction fee.

Smart Contract Properties

Field	Description
Admin Key	Sets the state of the instance and its fields can be modified arbitrarily if this key signs a transaction to modify it. If this is null, then such modifications are not possible, and there is no administrator that can override the normal operation of this smart contract instance. Note that if it is created with no admin keys, then there is no administrator to authorize changing the admin keys, so there can never be any admin keys for that instance.
Gas	The gas to run the constructor.
Initial Balance	The initial number of hbars to put into the cryptocurrency account associated with and owned by the smart contract.
Byte Code File	The file containing the hex encoded smart contract byte code.
Staked ID	The node account or node ID to which this contract account is staking to. See HIP-406. Note: Accounts cannot stake to contract accounts. This will be fixed in a future release.
Decline Rewards	Some contracts may choose to stake their hbars and decline receiving rewards. If set to true, the contract account will not earn rewards when staked. The default value is false. See HIP-406.
Auto Renew Account ID	An account to charge for auto-renewal of this contract. If not set, or set to an account with zero hbar balance, the contract’s own hbar balance will be used to cover auto-renewal fees.
Auto Renew Period	The period that the instance will charge its account every this many seconds to renew.
Automatic Token Associations	The maximum number of tokens that this contract can be automatically associated with (i.e., receive air-drops from).
Constructor Parameters	The constructor parameters to pass.
Memo	The memo to be associated with this contract. (max 100 bytes)

ContractCreateFlow()

The ContractCreateFlow()streamlines the creation of a contract by taking the bytecode of the contract and creating the file on Hedera to store the bytecode for you.

First, a FileCreateTransaction() will be executed to create a file on Hedera to store the specified contract bytecode. Then, the ContractCreateTransaction() will be executed to create the contract instance on Hedera. Lastly, a FileDeleteTransaction() will be executed to remove the file.

The response will return the contract create transaction information like the new contract ID. You will not get the ID of the file that was created that stored your contract bytecode. If you would like to know the file ID of your contract bytecode, you can create a file and use the ContractCreateTransaction() API directly.

Methods

Note: Please refer to ContractCreateTransaction() for a complete list of applicable methods.

Method	Type
setBytecode(<bytecode>)	byte
setBytecode(<bytecode>)	String
setBytecode(<bytecode>)	ByteString
setMaxChunks(<maxChunks)	int

Java

//Create the transaction
ContractCreateFlow contractCreate = new ContractCreateFlow()
     .setBytecode(bytecode)
     .setGas(100_000);

//Sign the transaction with the client operator key and submit to a Hedera network
TransactionResponse txResponse = contractCreate.execute(client);

//Get the receipt of the transaction
TransactionReceipt receipt = txResponse.getReceipt(client);

//Get the new contract ID
ContractId newContractId = receipt.contractId;
        
System.out.println("The new contract ID is " +newContractId);
//SDK Version: v2.10.0-beta.1

//Create the transaction
const contractCreate = new ContractCreateFlow()
    .setGas(100000)
    .setBytecode(bytecode);

//Sign the transaction with the client operator key and submit to a Hedera network
const txResponse = contractCreate.execute(client);

//Get the receipt of the transaction
const receipt = (await txResponse).getReceipt(client);

//Get the new contract ID
const newContractId = (await receipt).contractId;
        
console.log("The new contract ID is " +newContractId);
//SDK Version: v2.11.0-beta.1

//Create the transaction
contractCreate := hedera.NewContractCreateFlow().
		SetGas(100000).
		SetBytecode(byteCode)

//Sign the transaction with the client operator key and submit to a Hedera network
txResponse, err := contractCreate.Execute(client)
if err != nil {
		panic(err)
}

//Request the receipt of the transaction
receipt, err = txResponse.GetReceipt(client)
if err != nil {
		panic(err)
}

//Get the topic ID
newContractId := *receipt.ContractID

fmt.Printf("The new contract ID is %v\n", newContractId)
//SDK Version: 2.11.0-beta.1

// Create the admin key
let admin_key = PrivateKey::generate_ed25519();

// Create the transaction
let contract_create = ContractCreateFlow::new()
    .bytecode_hex(bytecode_hex)
    .admin_key(admin_key.public_key())
    .gas(100_000);
    .constructor_parameters(
        ContractFunctionParameters::new().add_string("Hello from Hedera.").to_bytes(None),
    )
    .contract_memo("[e2e::ContractCreateFlow]".to_owned())

// Sign the transaction with the client operator key and submit to a Hedera network
let tx_response = contract_create.execute(&client).await?;

// Get the receipt of the transaction
let receipt = tx_response.get_receipt(&client).await?;

// Get the new contract ID
let new_contract_id = receipt.contract_id.unwrap();
println!("The new contract ID is {:?}", new_contract_id);

// v0.34.0

ContractCreateTransaction()

Creates a smart contract instance using the file ID of the contract bytecode.

Constructor	Description
new ContractCreateTransaction()	Initializes the ContractCreateTransaction() object

Methods

Method	Type	Requirement
setGas(<gas>)	long	Required
setBytecodeFileId(<fileId>)	FileId	Required
setInitialBalance(<initialBalance>)	Hbar	Optional
setAdminKey(<keys>)	Key	Optional
setConstructorParameters(<constructorParameters>)	byte [ ]	Optional
setConstructorParameters(<constructorParameters>)	ContractFunctionParameters	Optional
setContractMemo(<memo>)	String	Optional
setStakedNodeId(<stakedNodeId>)	long	Optional
setStakedAccountId(<stakedAccountId>)	AccountId	Optional
setDeclineStakingReward(<declineStakingReward>)	boolean	Optional
setAutoRenewAccountId(<accountId)	AccountId	Optional
setAutoRenewPeriod(<autoRenewPeriod>)	Duration	Optional
setMaxAutomaticTokenAssociations()	int	Optional

Java

//Create the transaction
ContractCreateTransaction transaction = new ContractCreateTransaction()
    .setGas(100_000)
    .setBytecodeFileId(bytecodeFileId);
    
//Modify the default max transaction fee (default: 1 hbar)
ContractCreateTransaction modifyTransactionFee = transaction.setMaxTransactionFee(new Hbar(16));

//Sign the transaction with the client operator key and submit to a Hedera network
TransactionResponse txResponse = modifyTransactionFee.execute(client);

//Get the receipt of the transaction
TransactionReceipt receipt = txResponse.getReceipt(client);

//Get the new contract ID
ContractId newContractId = receipt.contractId;
        
System.out.println("The new contract ID is " +newContractId);
//v2.0.0

//Create the transaction
const transaction = new ContractCreateTransaction()
    .setGas(100_000)
    .setBytecodeFileId(bytecodeFileId);

//Modify the default max transaction fee (default: 1 hbar)
const modifyTransactionFee = transaction.setMaxTransactionFee(new Hbar(16));

//Sign the transaction with the client operator key and submit to a Hedera network
const txResponse = await modifyTransactionFee.execute(client);

//Get the receipt of the transaction
const receipt = await txResponse.getReceipt(client);

//Get the new contract ID
const newContractId = receipt.contractId;
        
console.log("The new contract ID is " +newContractId);

//Create the transaction
transaction := hedera.NewContractCreateTransaction().
		SetGas(100000).
		SetBytecodeFileID(byteCodeFileID)

//Sign the transaction with the client operator key and submit to a Hedera network
txResponse, err := transaction.Execute(client)
if err != nil {
		panic(err)
}

//Request the receipt of the transaction
receipt, err = txResponse.GetReceipt(client)
if err != nil {
		panic(err)
}

//Get the contract ID
newContractId := *receipt.ContractID

fmt.Printf("The new contract ID is %v\n", newContractId)
//v2.0.0

Get transaction values

Method	Type	Requirement
getAdminKey(<keys>)	Key	Optional
getGas(<gas>)	long	Optional
getInitialBalance(<initialBalance>)	Hbar	Optional
getBytecodeFileId(<fileId>)	FileId	Optional
getProxyAccountId(<accountId>)	AccountId	Optional
getConstructorParameters(<constructorParameters>)	ByteString	Optional
getContractMemo(<memo>)	String	Optional
getDeclineStakingReward()	boolean	Optional
getStakedNodeId()	long	Optional
getStakedAccountId()	AccountId	Optional
getAutoRenewAccountId()	AccountId	Required
getAutoRenewPeriod()	Duration	Required

Java

//Create the transaction
ContractCreateTransaction transaction = new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);

//Get admin key
transaction.getAdminKey()

//v2.0.0

//Create the transaction
const transaction = await new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);

//Get admin key
transaction.getAdminKey()

//v2.0.0

//Create the transaction
transaction := hedera.NewContractCreateTransaction().
		SetGas(500).
		SetBytecodeFileID(byteCodeFileID).
		SetAdminKey(adminKey)

//Get admin key
transaction.GetAdminKey()

//v2.0.0