Send a Data Message

An IndexationPayload is a payload type that can be used to attach arbitrary data and a key index to a message. To send a payload, you should at least provide the index. The data part (as bytes[]) is optional.

Java

You can use the ClientMessageBuilder.withDataString(data: String) function function to attach data to a message.

public static void getDataMessage() {
        Client iota = node();

        Message message = iota.message().withIndexString("Hello").withDataString("Tangle").finish();

        System.out.println("Message sent https://explorer.iota.org/devnet/message/" + message.id());

        MessageId[] fetched_message_ids = iota.getMessage().indexString("Hello");
        System.out.println("Messages with Hello index: " + Arrays.toString(fetched_message_ids));
    }

    

Output example:

{
   "message": {
      "networkId":"14379272398717627559",
      "parentMessageIds": [
         "1a383abbe5f6a6b0899d718975c3119643aa784a68d04075f4e986fd7a0c0e4b",
         "6098f889e31911833df7b7839e8b222d701ab496f7dfa1a719087edf4fa7ae52",
         "a98b47db4e8254eccc738c968bd35b08a5491e56d6c1a18af298c42bbd8c3a46",
         "da6796c0842c08de832c7948fffedc0d5adce372e50a108f26a128dba6096d31"
      ],
      "payload": {
         "type":2,
         "index":"494f54412e52532042494e44494e47202d204e4f44452e4a53",
         "data":"736f6d65207574662062617365642064617461"
      },
      "nonce":"13835058055282176519"
   },
   "messageId":"10f59c101cec669b0a0ba163bc777184c7f63455f5e771d42f910a1ba2ad20ff"
}

Nodejs

You can use the MessageSender.data(data: string | Uint8Arra) function function to attach data to a message.

async function run() {
    const { ClientBuilder } = require('@iota/client');

    // client will connect to testnet by default
    const client = new ClientBuilder().build();

    const message = await client.message()
        .index('IOTA.RS BINDING - NODE.JS')
        .data('some utf based data')
        .submit();

    console.log(message);
}

run()

Output example:

{
  "message": {
    "networkId": "14379272398717627559",
    "parentMessageIds": [
      "1a383abbe5f6a6b0899d718975c3119643aa784a68d04075f4e986fd7a0c0e4b",
      "6098f889e31911833df7b7839e8b222d701ab496f7dfa1a719087edf4fa7ae52",
      "a98b47db4e8254eccc738c968bd35b08a5491e56d6c1a18af298c42bbd8c3a46",
      "da6796c0842c08de832c7948fffedc0d5adce372e50a108f26a128dba6096d31"
    ],
    "payload": {
      "type": 2,
      "index": "494f54412e52532042494e44494e47202d204e4f44452e4a53",
      "data": "736f6d65207574662062617365642064617461"
    },
    "nonce": "13835058055282176519"
  },
  "messageId": "10f59c101cec669b0a0ba163bc777184c7f63455f5e771d42f910a1ba2ad20ff"
}

Python

You can use the data parameter in the Client.message() function to attach data to a message.

import iota_client
client = iota_client.Client()

# encoding utf string into list of bytes
some_utf_data = "some utf based data".encode("utf8")

message = client.message(
    index="some_data_index", data=some_utf_data
)
print(message)

Output example:

{
  "message_id": "8d4fa37be3c00691131c2c3e03e7b8b956c9118a2ce4be3a8597d51d82ed2de9",
  "network_id": 7712883261355838377,
  "parents": [
    "3719d308ae14b7ef1ed5a3a1604228e97587b9da487db10bc6e4a4f800083da0",
    "4431e2f776db888488728e0aa34c94975e65d6fa74893aa675172af6b9f37257",
    "8f9fa84954c58bcfc9acc33ca827b4ea35c2caae88db736399a031120e85eebf",
    "f63d416de97e6a9fd1314fbbbbb263f30dff260f3075f9a65e7dfe1f2cc56ce3"
  ],
  "payload": {
    "transaction": "None",
    "milestone": "None",
    "indexation": [
      {
        "index": "736f6d655f646174615f696e646578",
        "data": [115, 111, 109, 101, 32, 117, 116, 102, 32, 98, 97, 115, 101, 100, 32, 100, 97, 116, 97]
      }
    ],
    "receipt": "None",
    "treasury_transaction": "None"
  },
  "nonce": 6917529027641573188
}

Rust

You can use the ClientMessageBuilder.with_data(data: Vec<u8>) function to sent data in a message.

// Copyright 2021 IOTA Stiftung
// SPDX-License-Identifier: Apache-2.0

//! cargo run --example 08_data_message --release

use iota_client::{Client, Result};

/// In this example we will send a message without a payload

#[tokio::main]
async fn main() -> Result<()> {
    let iota = Client::builder()
        .with_node("https://api.lb-0.h.chrysalis-devnet.iota.cafe")?
        // .with_permanode("http://18.196.167.57:8000/api/permanode/", None, None)?
        .finish()
        .await?;

    let message = iota
        .message()
        .with_index("Hello")
        .with_data("Tangle".as_bytes().to_vec())
        .finish()
        .await?;

    println!(
        "Message sent https://explorer.iota.org/devnet/message/{}\n",
        message.id().0
    );

    let fetched_message_ids = iota.get_message().index("Hello").await.unwrap();
    println!("Messages with Hello index: {fetched_message_ids:?}");
    Ok(())
}

Output example:

{
  "message": {
    "networkId": "14379272398717627559",
    "parentMessageIds": [
      "1a383abbe5f6a6b0899d718975c3119643aa784a68d04075f4e986fd7a0c0e4b",
      "6098f889e31911833df7b7839e8b222d701ab496f7dfa1a719087edf4fa7ae52",
      "a98b47db4e8254eccc738c968bd35b08a5491e56d6c1a18af298c42bbd8c3a46",
      "da6796c0842c08de832c7948fffedc0d5adce372e50a108f26a128dba6096d31"
    ],
    "payload": {
      "type": 2,
      "index": "494f54412e52532042494e44494e47202d204e4f44452e4a53",
      "data": "736f6d65207574662062617365642064617461"
    },
    "nonce": "13835058055282176519"
  },
  "messageId": "10f59c101cec669b0a0ba163bc777184c7f63455f5e771d42f910a1ba2ad20ff"
}

Wasm

You can use the MessageBuilder.data(data: Uint8Array) function function to attach data to a message.

async function run() {
    const { ClientBuilder } = require('@iota/client');

    // client will connect to testnet by default
    const client = new ClientBuilder().build();

    const message = await client.message()
        .index('IOTA.RS BINDING - NODE.JS')
        .data('some utf based data')
        .submit();

    console.log(message);
}

run()

Output example:

{
  "message": {
    "networkId": "14379272398717627559",
    "parentMessageIds": [
      "1a383abbe5f6a6b0899d718975c3119643aa784a68d04075f4e986fd7a0c0e4b",
      "6098f889e31911833df7b7839e8b222d701ab496f7dfa1a719087edf4fa7ae52",
      "a98b47db4e8254eccc738c968bd35b08a5491e56d6c1a18af298c42bbd8c3a46",
      "da6796c0842c08de832c7948fffedc0d5adce372e50a108f26a128dba6096d31"
    ],
    "payload": {
      "type": 2,
      "index": "494f54412e52532042494e44494e47202d204e4f44452e4a53",
      "data": "736f6d65207574662062617365642064617461"
    },
    "nonce": "13835058055282176519"
  },
  "messageId": "10f59c101cec669b0a0ba163bc777184c7f63455f5e771d42f910a1ba2ad20ff"
}

• You can find the message using its message ID in the Tangle explorer.
• There are three prepared payloads(transaction, milestone, and indexation). However, at the time, the indexation payload is the only one in use.
• data contains arbitrary data encoded in bytes.
• Please note there is no IOTA address involved while sending data messages. Data messages are referenced using their message ID or index key.
• IOTA addresses are part of the UTXO data structure that is sent using the SignedTransaction payload.