Create a smart contract

Before you get started with smart contracts consider if the Hedera Token Service is better for your use case. For most, it provides greater performance and lower costs. Learn more in the blog series, Getting Started with Hedera Token Service.
A transaction that creates a new contract instance. After the contract is created you can get the new contract ID by requesting the receipt of the transaction. You will first need to create a file that stores the bytecode of the contract. Then you will create the smart contract instance  that will run the bytecode stored in the given file, referenced either by file ID or by the transaction ID of the transaction that created the file. The constructor will be executed using the given amount of gas. Similar to accounts the instance will exist for autoRenewPeriod seconds. When that is reached, it will renew itself for another autoRenewPeriod seconds by charging its associated cryptocurrency account (which it creates here). If it has insufficient cryptocurrency to extend that long, it will extend as long as it can. If its balance is zero, the instance will be deleted.
Solidity Support
Hedera smart contracts support Solidity versions up to v0.5.9.
Smart Contract State Size
Each smart contract has a maximum state size of 1MB which can store up to approximately 16,000 key-value pairs.
Transaction Signing Requirements
The client operator account is required to sign the transaction
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 smart contract byte code.
Proxy Account
The ID of the account to which this account is proxy staked. If proxyAccountID is null, or is an invalid account, or is an account that isn't a node, then this account is automatically proxy staked to a node chosen by the network, but without earning payments. If the proxyAccountID account refuses to accept proxy staking , or if it is not currently running a node, then it will behave as if proxyAccountID was null.
Auto Renew Period
The period that the instance will charge its account every this many seconds to renew.
Constructor Parameters
The constructor parameters to pass.
Memo
The memo to be associated with this contract.
Constructor
Description
new ContractCreateTransaction()
Initializes the ContractCreateTransaction()
new ContractCreateTransaction()
Methods
V2
V1
V2
Method
Type
Requirement
setGas(<gas>)
long
Required
setBytecodeFileId(<fileId>)
FileId
Required
setInitialBalance(<initialBalance>)
Hbar
Optional
setAdminKey(<keys>)
PublicKey
Optional
setProxyAccountId(<accountId>)
AccountId
Optional
setConstructorParameters(<constructorParameters>)
byte [ ]
Optional
setConstructorParameters(<constructorParameters>)
ContractFunctionParameters
Optional
setContractMemo(<memo>)
String
Optional
setAutoRenewPeriod(<autoRenewPeriod>)
Duration
Optional
Java
//Create the transaction
ContractCreateTransaction transaction = new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);
    
//Modify the default max transaction fee (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
JavaScript
//Create the transaction
const transaction = new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);
​
//Modify the default max transaction fee (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);
​
Go
//Create the transaction
transaction := hedera.NewContractCreateTransaction().
		SetGas(500).
		SetBytecodeFileID(byteCodeFileID).
		SetAdminKey(adminKey)
​
//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 topic ID
newContractId := *receipt.ContractID
​
fmt.Printf("The new topic ID is %v\n", newContractId)
//v2.0.0
V1
Method
Type
Requirement
setGas(<gas>)
long
Required
setBytecodeFileId(<fileId>)
FileId
Required
setInitialBalance(<initialBalance>)
long/Hbar
Optional
setAdminKey(<publicKeys>)
Ed25519PublicKey
Optional
setProxyAccountId(<accountId>)
AccountId
Optional
setConstructorParameters(<constructorParameters>)
byte [ ]
Optional
setConstructorParameters(<constructorParameters>)
ContractFunctionParameters
Optional
setContractMemo(<memo>)
String
Optional
setAutoRenewPeriod(<autoRenewPeriod>)
Duration
Optional
Java
//Create the transaction
ContractCreateTransaction transaction = new ContractCreateTransaction()
     .setBytecodeFileId(fileId)
     .setGas(100_000_000)
     .setConstructorParams(new ContractFunctionParams().addString("hello from hedera!"));
​
//Sign with the client operator account private key, submit to a Hedera network        
TransactionId txId = transaction.execute(client);
​
//Get the receipt of the transaction
TransactionReceipt receipt = txId.getReceipt(client);
​
//Get the new contract ID
ContractId newContractId = receipt.getContractId();
        
System.out.println("The new contract ID is " + newContractId);
​
//v1.3.2
JavaScript
//Create the transaction
const transaction = new ContractCreateTransaction()
     .setBytecodeFileId(fileId)
     .setGas(100_000_000)
     .setConstructorParams(new ContractFunctionParams().addString("hello from hedera!"));
​
//Sign with the client operator account private key, submit to a Hedera network        
const txId = await transaction.execute(client);
​
//Get the receipt of the transaction
const receipt = await txId.getReceipt(client);
​
//Get the new contract ID
const newContractId = receipt.getContractId();
        
System.out.println("The new contract ID is " + newContractId);
​
//v1.4.4
​
Get transaction values
V2
V2
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
getAutoRenewPeriod(<autoRenewPeriod>)
Duration
Optional
Java
//Create the transaction
ContractCreateTransaction transaction = new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);
​
//Get admin key
transaction.getAdminKey()
​
//v2.0.0
JavaScript
//Create the transaction
const transaction = await new ContractCreateTransaction()
    .setGas(500)
    .setBytecodeFileId(bytecodeFileId)
    .setAdminKey(adminKey);
​
//Get admin key
transaction.getAdminKey()
​
//v2.0.0
Go
//Create the transaction
transaction := hedera.NewContractCreateTransaction().
		SetGas(500).
		SetBytecodeFileID(byteCodeFileID).
		SetAdminKey(adminKey)
​
//Get admin key
transaction.GetAdminKey()
​
//v2.0.0
​
​

Smart Contract Service

Update a smart contract

Last updated 1 week ago

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 smart contract byte code.
Proxy Account	The ID of the account to which this account is proxy staked. If proxyAccountID is null, or is an invalid account, or is an account that isn't a node, then this account is automatically proxy staked to a node chosen by the network, but without earning payments. If the proxyAccountID account refuses to accept proxy staking , or if it is not currently running a node, then it will behave as if proxyAccountID was null.
Auto Renew Period	The period that the instance will charge its account every this many seconds to renew.
Constructor Parameters	The constructor parameters to pass.
Memo	The memo to be associated with this contract.

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

Method	Type	Requirement
`setGas(<gas>)`	long	Required
`setBytecodeFileId(<fileId>)`	FileId	Required
`setInitialBalance(<initialBalance>)`	Hbar	Optional
`setAdminKey(<keys>)`	PublicKey	Optional
`setProxyAccountId(<accountId>`)	AccountId	Optional
`setConstructorParameters(<constructorParameters>)`	byte [ ]	Optional
`setConstructorParameters(<constructorParameters>)`	ContractFunctionParameters	Optional
`setContractMemo(<memo>)`	String	Optional
`setAutoRenewPeriod(<autoRenewPeriod>)`	Duration	Optional

Create a smart contract

Methods

Get transaction values

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