> ## Documentation Index > Fetch the complete documentation index at: https://hedera-0c6e0218-docs-evm-account-model.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Submit a message > Submit a topic message to Hedera Consensus Service, configure max chunks and chunk size, and set custom fee limits when paying HCS topic fees. 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. ## **Custom Fee Payment** If a topic has custom fees enabled, users submitting messages must pay the required fee in **HBAR or HTS fungible tokens**. If `setCustomFeeLimits` is not specified in the transaction, the user would need to pay any fee associated with that topic ID. The transaction will only fail if the user does not have sufficient assets to cover the fee. **Recommendation:** To avoid unexpected fees, it is strongly recommended to use `setCustomFeeLimits` when submitting a message. This ensures that only the intended fee structure is applied, providing a safeguard against unintended charges. ```java theme={null} TopicMessageSubmitTransaction() .setTopicId() .setMessage() .setCustomFeeLimits() // Ensure this covers the required amount .execute(client); ``` ## **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** * Each transaction incurs a standard Hedera network fee based on network resource usage. * If a custom fee is set for a topic, users submitting messages must pay this fee in HBAR or HTS tokens. * The Fee Schedule Key allows authorized users to update fee structures. If set, it must sign transactions modifying fees. * If the topic has custom fees, the sender must have sufficient balance to cover the fees unless they are exempt via the Fee Exempt Key List. It is recommended to use `setCustomFeeLimits` on the `TopicMessageSubmitTransaction` to ensure the expected fee structure is applied and avoid unexpected transaction failures due to insufficient funds. * If you submit a message to a topic with a custom fee, the cost changes from the baseline $0.0001 USD to roughly $0.05 USD per `TopicMessageSubmitTransaction`. * Use the [query fees table](/learn/networks/mainnet/fees#consensus-service) for the base transaction fee and the [Hedera Fee Estimator](https://hedera.com/fees) to estimate standard network fees. ## Methods
Method Type Description Requirement
setTopicId(\) TopicId The topic ID to submit the message to Required
setMessage(\) String The message in a String format Optional
setMessage(\) byte \[ ] The message in a byte array format Optional
setMessage(\) 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
setCustomFeeLimits() List\ The maximum custom fees the sender is willing to pay Optional
addCustomFeeLimit() CustomFeeLimit Adds a custom fee limit Optional
```java Java highlight={18} theme={null} //Create the transaction TopicMessageSubmitTransaction transaction = new TopicMessageSubmitTransaction() .setTopicId(newTopicId) .setMessage("hello, HCS! ") .setCustomFeeLimits(maxCustomFees); // Set custom fee limits if applicable //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 JavaScript theme={null} // Create the transaction const transaction = await new TopicMessageSubmitTransaction() .setTopicId(newTopicId) .setMessage("Hello, HCS!") .setCustomFeeLimits(maxCustomFees); // Set custom fee limits if applicable // Execute transaction const txResponse = await transaction.execute(client); // Request the receipt const receipt = await txResponse.getReceipt(client); // Get the transaction consensus status console.log("Transaction Status:", receipt.status); //v2.0.0 ``` ```java Go theme={null} //Create the transaction transaction := hedera.NewTopicSubmitTransaction(). SetTopicID(topicID). SetMessage([]byte(content)). SetCustomFeeLimits(maxCustomFees) // Set custom fee limits if applicable //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 ``` ```rust Rust theme={null} // Create the transaction let transaction = TopicMessageSubmitTransaction::new() .topic_id(topic_id) .message("Hello, HCS!") .custom_fee_limits(max_custom_fees); // Set custom fee limits if applicable // Sign with the client operator key and submit to a Hedera network let tx_response = transaction.execute(&client).await?; // Request the receipt of the transaction let receipt = tx_response.get_receipt(&client).await?; // Get the transaction consensus status let status = receipt.status; println!("The transaction consensus status is {:?}", status); // v0.34.0 ``` ## Get transaction values | Method | Type | Description | | ---------------------- | ---------- | ------------------------------------------------ | | `getTopicId()` | TopicId | The topic ID to submit the message to | | `getMessage()` | ByteString | The message being submitted | | `getCustomFeeLimits()` | Fee\[] | Extract the custom fee limits of the transaction | ```java Java theme={null} //Create the transaction TopicMessageSubmitTransaction transaction = new TopicMessageSubmitTransaction() .setTopicId(newTopicId) .setMessage("hello, HCS! "); //Get the transaction message ByteString getMessage = transaction.getMessage(); //v2.0.0 ``` ```javascript JavaScript theme={null} //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 Go theme={null} //Create the transaction transaction := hedera.NewTopicSubmitTransaction(). SetTopicID(topicID). SetMessage([]byte(content)) //Get the transaction message getMessage := transaction.GetMessage() //v2.0.0 ```