Submit a message

A transaction that submits a topic message to the Hedera network. To access the messages submitted to a topic ID, subscribe to the topic via a mirror node. The mirror node will publish the ordered messages to subscribers. Once the transaction is successfully executed, the receipt of the transaction will include the topic's updated sequence number and topic running hash.

Max Chunks

The max chunks setting defines the maximum number of chunks into which a given message can be split. The default value is 20 chunks, meaning a message can consist of up to 20 chunks by default. This value can be modified using the setMaxChunks method. Max Chunk Size

🚨 NOTE: Max size of an HCS message: 1024 bytes (1 kb).

The max chunk size refers to the maximum size (in bytes) of each individual chunk of a message. By default, the max chunk size is 1024 bytes (1 KB). This value can be modified using the setChunkSize method.

Transaction Signing Requirements

• Anyone can submit a message to a public topic

• The submitKey is required to sign the transaction for a private topic

Transaction Fees

• Please see the transaction and query fees table for base transaction fee

• Please use the Hedera fee estimator to estimate your transaction fee cost

Methods

Method	Type	Description	Requirement
setTopicId(<topicId>)	TopicId	The topic ID to submit the message to	Required
setMessage(<message>)	String	The message in a String format	Optional
setMessage(<message>)	byte [ ]	The message in a byte array format	Optional
setMessage(<message>)	ByteString	The message in a ByteString format	Optional
setChunkSize()	int	The max size of individual chunk for a given message. Default: 1024 bytes	Optional
setMaxChunks()	int	The max number of chunks a given message can be split into. Default: 20	Optional

Java

//Create the transaction
TopicMessageSubmitTransaction transaction = new TopicMessageSubmitTransaction()
    .setTopicId(newTopicId)
    .setMessage("hello, HCS! ");

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

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

//Get the transaction consensus status
Status transactionStatus = receipt.status;

System.out.println("The transaction consensus status is " +transactionStatus);
//v2.0.0

JavaScript

//Create the transaction
await new TopicMessageSubmitTransaction({
        topicId: createReceipt.topicId,
        message: "Hello World",
    }).execute(client);

//v2.0.0

Go

//Create the transaction
transaction := hedera.NewTopicSubmitTransaction().
        SetTopicID(topicID).
        SetMessage([]byte(content))

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

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

//Get the transaction consensus status
transactionStatus := receipt.Status

fmt.Printf("The transaction consensus status is %v\n", transactionStatus)
//v2.0.0

Get transaction values

Method	Type	Description
getTopicId()	TopicId	The topic ID to submit the message to
getMessage()	ByteString	The message being submitted
getAllTransactionHash()	byte [ ]	The hash for each transaction

Java

//Create the transaction
TopicMessageSubmitTransaction transaction = new TopicMessageSubmitTransaction()
    .setTopicId(newTopicId)
    .setMessage("hello, HCS! ");

//Get the transaction message
ByteString getMessage = transaction.getMessage();
//v2.0.0

JavaScript

//Create the transaction
const transaction = await new TopicMessageSubmitTransaction()
    .setTopicId(newTopicId)
    .setMessage("hello, HCS! ");

//Get the transaction message
const getMessage = transaction.getMessage();

//v2.0.0

Go

//Create the transaction
transaction := hedera.NewTopicSubmitTransaction().
        SetTopicID(topicID).
        SetMessage([]byte(content))

//Get the transaction message
getMessage := transaction.GetMessage()
//v2.0.0