Signing Clients

Signing clients extend their read-only counterparts with the ability to build, sign, and broadcast transactions. They require a signer (wallet) and are created via static factory methods.

Signers

A signer is any object that holds keys and can produce signatures. CosmJS supports two signing modes:

Interface	Signing Mode	Wallet Implementation
`OfflineDirectSigner`	Protobuf (Direct) — recommended	`DirectSecp256k1HdWallet`, `DirectSecp256k1Wallet`
`OfflineAminoSigner`	Amino JSON — required for Ledger	`Secp256k1HdWallet`, Ledger signers

Both implement getAccounts() to list available accounts. The signing client auto-detects which mode to use based on whether the signer has a signDirect method.

import { DirectSecp256k1HdWallet } from "@cosmjs/proto-signing";

const wallet = await DirectSecp256k1HdWallet.fromMnemonic("your mnemonic ...", {
  prefix: "cosmos",
});

SigningStargateClient

import { SigningStargateClient, GasPrice } from "@cosmjs/stargate";

const client = await SigningStargateClient.connectWithSigner(
  "https://rpc.my-chain.network",
  wallet,
  { gasPrice: GasPrice.fromString("0.025uatom") },
);

Factory Methods

Method	Description
`connectWithSigner(endpoint, signer, options?)`	Connect to RPC and create signing client
`createWithSigner(cometClient, signer, options?)`	Create from existing CometBFT client
`offline(signer, options?)`	Offline client (sign without RPC)

Transaction Methods

Method	Description
`signAndBroadcast(address, messages, fee, memo?, timeoutHeight?)`	Sign, broadcast, and wait for inclusion
`signAndBroadcastSync(address, messages, fee, memo?, timeoutHeight?)`	Sign and broadcast, return tx hash immediately
`sign(address, messages, fee, memo, signerData?, timeoutHeight?)`	Sign without broadcasting (returns `TxRaw`). `memo` is required — pass `""` to omit.
`simulate(address, messages, memo)`	Estimate gas for a transaction (`memo` is `string \| undefined`, not optional — pass `undefined` explicitly)

Convenience Methods

Method	Message Type
`sendTokens(sender, recipient, amount, fee, memo?)`	`MsgSend`
`delegateTokens(delegator, validator, amount, fee, memo?)`	`MsgDelegate`
`undelegateTokens(delegator, validator, amount, fee, memo?)`	`MsgUndelegate`
`withdrawRewards(delegator, validator, fee, memo?)`	`MsgWithdrawDelegatorReward`

Fees

The fee parameter accepts three forms:

// Explicit fee
const fee: StdFee = { amount: [{ denom: "uatom", amount: "5000" }], gas: "200000" };
await client.signAndBroadcast(address, messages, fee);

// Auto-calculate from simulation (requires gasPrice in options)
await client.signAndBroadcast(address, messages, "auto");

// Auto with gas multiplier (1.4 = 40% buffer over simulated gas)
await client.signAndBroadcast(address, messages, 1.4);

Options

interface SigningStargateClientOptions extends StargateClientOptions {
  readonly registry?: Registry;
  readonly aminoTypes?: AminoTypes;
  readonly broadcastTimeoutMs?: number;
  readonly broadcastPollIntervalMs?: number;
  readonly gasPrice?: GasPrice | DynamicGasPriceConfig;
}

registry — protobuf type registry for encoding messages (defaults cover all standard Cosmos SDK message types)
aminoTypes — converters between protobuf and Amino for Amino signers
gasPrice — required when using "auto" fees; supports static pricing or dynamic fee market pricing via DynamicGasPriceConfig

SigningCosmWasmClient

Extends CosmWasmClient with signing and smart contract transaction methods.

import { SigningCosmWasmClient } from "@cosmjs/cosmwasm";

const client = await SigningCosmWasmClient.connectWithSigner(
  "https://rpc.my-chain.network",
  wallet,
  { gasPrice: GasPrice.fromString("0.025uosmo") },
);

CosmWasm-Specific Transaction Methods

Method	Description
`upload(sender, wasmCode, fee, memo?, instantiatePermission?)`	Upload wasm bytecode
`instantiate(sender, codeId, msg, label, fee, options?)`	Instantiate a contract
`instantiate2(sender, codeId, salt, msg, label, fee, options?)`	Instantiate with predictable address
`execute(sender, contract, msg, fee, memo?, funds?)`	Execute a contract message
`executeMultiple(sender, instructions, fee, memo?)`	Execute multiple contract messages in one tx
`migrate(sender, contract, codeId, msg, fee, memo?)`	Migrate a contract to new code
`updateAdmin(sender, contract, newAdmin, fee, memo?)`	Change contract admin
`clearAdmin(sender, contract, fee, memo?)`	Remove contract admin

SigningCosmWasmClient also includes all the convenience methods from SigningStargateClient (sendTokens, delegateTokens, etc.) as well as signAndBroadcast, sign, and simulate.

const uploadResult = await client.upload(address, wasmBytecode, "auto");

const { contractAddress } = await client.instantiate(
  address,
  uploadResult.codeId,
  { count: 0 },
  "my-counter",
  "auto",
);

const execResult = await client.execute(
  address,
  contractAddress,
  { increment: {} },
  "auto",
);

CosmJS

Concepts

Guides

API Reference

Signers

SigningStargateClient

Factory Methods

Transaction Methods

Convenience Methods

Fees

Options

SigningCosmWasmClient

CosmWasm-Specific Transaction Methods

Next Steps

Send Transactions

Fees and Gas

​Signers

​SigningStargateClient

​Factory Methods

​Transaction Methods

​Convenience Methods

​Fees

​Options

​SigningCosmWasmClient

​CosmWasm-Specific Transaction Methods

​Next Steps

Send Transactions

Fees and Gas

Signers

SigningStargateClient

Factory Methods

Transaction Methods

Convenience Methods

Fees

Options

SigningCosmWasmClient

CosmWasm-Specific Transaction Methods

Next Steps