Gas and Advanced Usage

This page covers gas configuration for CosmWasm transactions, building custom encode objects, working with the CosmWasm Binary type, and using the low-level wasm query extension for fine-grained pagination.

Gas Estimation

Auto Gas

When you pass "auto" as the fee, the client simulates the transaction and applies a gas multiplier:

Operation	Default Multiplier	Reason
`upload`	1.1x	Upload simulation is very accurate
All others	1.4x	General safety margin for state changes

You can pass a numeric multiplier instead of "auto" for finer control:

const result = await client.execute(
  address,
  contractAddress,
  { complex_operation: {} },
  1.6,
);

Static Fees

For full control, provide an explicit fee object:

import { coins } from "@cosmjs/stargate";

const fee = {
  amount: coins(5000, "uosmo"),
  gas: "300000",
};

const result = await client.execute(address, contractAddress, { increment: {} }, fee);

Gas Simulation

Simulate a transaction to estimate gas without broadcasting:

import { toUtf8 } from "@cosmjs/encoding";
import { MsgExecuteContract } from "cosmjs-types/cosmwasm/wasm/v1/tx";

const msg = {
  typeUrl: "/cosmwasm.wasm.v1.MsgExecuteContract",
  value: MsgExecuteContract.fromPartial({
    sender: address,
    contract: contractAddress,
    msg: toUtf8(JSON.stringify({ increment: {} })),
    funds: [],
  }),
};

const gasEstimate = await client.simulate(address, [msg], "estimating gas");

Working with Binary Data

The toBinary and fromBinary helpers convert JavaScript objects to and from the base64-encoded JSON format used by CosmWasm Binary fields:

import { toBinary, fromBinary } from "@cosmjs/cosmwasm";

const encoded = toBinary({ some: "data" });
// "eyJzb21lIjoiZGF0YSJ9"

const decoded = fromBinary(encoded);
// { some: "data" }

This is useful when composing nested messages, such as sending a sub-message through a contract:

await client.execute(
  address,
  multisigAddress,
  {
    propose: {
      msg: toBinary({ transfer: { recipient: "osmo1...", amount: "1000000" } }),
    },
  },
  "auto",
);

Building Custom Messages

For advanced use cases, construct CosmWasm encode objects directly and broadcast them via signAndBroadcast:

import { toUtf8 } from "@cosmjs/encoding";
import { MsgExecuteContract } from "cosmjs-types/cosmwasm/wasm/v1/tx";

const msg = {
  typeUrl: "/cosmwasm.wasm.v1.MsgExecuteContract",
  value: MsgExecuteContract.fromPartial({
    sender: address,
    contract: contractAddress,
    msg: toUtf8(JSON.stringify({ increment: {} })),
    funds: [{ denom: "uosmo", amount: "1000" }],
  }),
};

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

Mixing CosmWasm and Cosmos SDK Messages

This approach lets you combine contract calls with standard Cosmos SDK messages in a single atomic transaction:

import { toUtf8 } from "@cosmjs/encoding";
import { MsgExecuteContract } from "cosmjs-types/cosmwasm/wasm/v1/tx";

const executeMsg = {
  typeUrl: "/cosmwasm.wasm.v1.MsgExecuteContract",
  value: MsgExecuteContract.fromPartial({
    sender: address,
    contract: contractAddress,
    msg: toUtf8(JSON.stringify({ claim_rewards: {} })),
    funds: [],
  }),
};

const sendMsg = {
  typeUrl: "/cosmos.bank.v1beta1.MsgSend",
  value: {
    fromAddress: address,
    toAddress: "osmo1recipient...",
    amount: [{ denom: "uosmo", amount: "500000" }],
  },
};

const result = await client.signAndBroadcast(address, [executeMsg, sendMsg], "auto");

Wasm Query Extension

For fine-grained control over pagination or when building a custom query client, use the wasm extension directly instead of the high-level CosmWasmClient methods:

import { QueryClient } from "@cosmjs/stargate";
import { setupWasmExtension } from "@cosmjs/cosmwasm";
import { connectComet } from "@cosmjs/tendermint-rpc";

const cometClient = await connectComet("https://rpc.my-chain.network");
const queryClient = QueryClient.withExtensions(cometClient, setupWasmExtension);

const { codeInfos, pagination } = await queryClient.wasm.listCodeInfo();
const allState = await queryClient.wasm.getAllContractState("osmo1contractaddr...");

Available Extension Methods

Method	Description
`listCodeInfo(paginationKey?)`	List all uploaded codes
`getCode(id)`	Download original Wasm by code ID
`listContractsByCodeId(id, paginationKey?)`	List contract addresses for a code ID
`listContractsByCreator(creator, paginationKey?)`	List contracts created by an address
`getContractInfo(address)`	Get contract metadata
`getContractCodeHistory(address, paginationKey?)`	Get migration history
`getAllContractState(address, paginationKey?)`	Dump all contract storage
`queryContractRaw(address, key)`	Read a single storage key
`queryContractSmart(address, query)`	Execute a smart query

CosmJS

Concepts

Guides

API Reference

Gas and Advanced Usage

Gas Estimation

Auto Gas

Static Fees

Gas Simulation

Working with Binary Data

Building Custom Messages

Mixing CosmWasm and Cosmos SDK Messages

Wasm Query Extension

Available Extension Methods

Next Steps

CosmWasm Overview

Stargate vs CosmWasm

​Gas Estimation

​Auto Gas

​Static Fees

​Gas Simulation

​Working with Binary Data

​Building Custom Messages

​Mixing CosmWasm and Cosmos SDK Messages

​Wasm Query Extension

​Available Extension Methods

​Next Steps

CosmWasm Overview

Stargate vs CosmWasm

Gas Estimation

Auto Gas

Static Fees

Gas Simulation

Working with Binary Data

Building Custom Messages

Mixing CosmWasm and Cosmos SDK Messages

Wasm Query Extension

Available Extension Methods

Next Steps