Building Messages

Construct message objects for token transfers, staking, and multi-message transactions

Every Cosmos SDK transaction contains one or more messages — typed instructions that tell the chain what to do. In CosmJS, messages are represented as EncodeObject values: a typeUrl string paired with a Protobuf message value.

Token Transfer (MsgSend)

import { MsgSend } from "cosmjs-types/cosmos/bank/v1beta1/tx";
import { coins } from "@cosmjs/proto-signing";

const sendMsg = {
  typeUrl: "/cosmos.bank.v1beta1.MsgSend",
  value: MsgSend.fromPartial({
    fromAddress: senderAddress,
    toAddress: "cosmos1recipientaddress...",
    amount: coins(1_000_000, "uatom"),
  }),
};

MsgSend.fromPartial() creates a message from a partial object, filling in defaults for missing fields. The coins helper builds the [{ denom, amount }] array.

Staking Delegation

import { MsgDelegate } from "cosmjs-types/cosmos/staking/v1beta1/tx";

const delegateMsg = {
  typeUrl: "/cosmos.staking.v1beta1.MsgDelegate",
  value: MsgDelegate.fromPartial({
    delegatorAddress: senderAddress,
    validatorAddress: "cosmosvaloper1...",
    amount: { denom: "uatom", amount: "1000000" },
  }),
};

Multiple Messages in One Transaction

A single transaction can carry multiple messages. They execute atomically — all succeed or all fail:

const messages = [sendMsg, delegateMsg];
const result = await client.signAndBroadcast(senderAddress, messages, "auto");

For type-safe message construction, use typed encode objects like MsgSendEncodeObject from @cosmjs/stargate. See EncodeObject for the full list.

Next Steps

Simulating Gas

Estimate how much gas your messages will consume before broadcasting.

Custom Message Types

Register your own Protobuf message types with the Registry.