Signing overview

Every app integration follows the same pipeline:

Never embed mnemonics in production apps. Use Cosmos Kit, SecureStore (mobile), or hardware keys.

Web (CosmJS)

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

const client = await SigningStargateClient.connectWithSigner(RPC, offlineSigner, {
  gasPrice: { denom: 'usaf', amount: '0.05' },
});

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

With Cosmos Kit, offlineSigner comes from getOfflineSigner(chainId).

React Native

Same CosmJS APIs. Load mnemonic from expo-secure-store only in self-custody wallets; prefer WalletConnect for external signers.

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

Flutter (CosmJS)

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

const client = await SigningStargateClient.connectWithSigner(RPC, offlineSigner, {
  gasPrice: { denom: 'usaf', amount: '0.05' },
});

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

Same CosmJS APIs as web and React Native. For Keplr / Leap Mobile, use Cosmos Kit WalletConnect.

Signer sources

Path	When
Cosmos Kit	Browser dApp or mobile via WalletConnect
CosmJS DirectSecp256k1HdWallet	RN, Flutter (JS bridge), scripts, dev only
safrochaind tx	Debugging, CI, operators

Advanced authorization

Feature	Infra docs
Fee grants (sponsor gas)	CLI tx, feegrant module
Authz (delegate msgs)	CLI tx, authz module
FeePay sponsored txs	feepay module

Next steps

• Simulate gas and fees
• Broadcast modes