Broadcast modes

After signing, CometBFT accepts the tx via RPC broadcast_tx_* methods. CosmJS signAndBroadcast uses sync by default and waits for CheckTx.

Web

import { assertIsDeliverTxSuccess } from '@cosmjs/stargate';

const result = await client.signAndBroadcast(sender, [msg], 'auto');
assertIsDeliverTxSuccess(result);
console.log(result.transactionHash, result.height);

React Native

assertIsDeliverTxSuccess(result);
// Poll REST /cosmos/tx/v1beta1/txs/{hash} if you need deliver confirmation on slow RPC

Flutter (CosmJS)

import { assertIsDeliverTxSuccess } from '@cosmjs/stargate';

const result = await client.signAndBroadcast(sender, [msg], 'auto');
assertIsDeliverTxSuccess(result);

Broadcast modes

Mode	Behavior
sync	Returns after CheckTx (CosmJS default)
async	Returns immediately after mempool accept
block	Waits until tx is included in a block

Common errors

Error	Cause	Fix
account sequence mismatch	Stale sequence	Re-fetch account, rebuild tx
insufficient fees	Below globalfee min	Use 0.05usaf gas prices
out of gas	Gas limit too low	Simulate with higher adjustment

Offline and multisig

Generate an unsigned tx for hardware or multisig co-signers:

safrochaind tx bank send ... --generate-only > unsigned.json

Full flag reference: CLI tx.

Next

• Signing overview
• IBC transfers