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CosmosJS - Cosmos JavaScript Library

Developed / Developing by Cosmostation

A Javascript Open Source Library for blockchain made using by Cosmos SDK like Cosmoshub, IRISnet, Akash Network, and Juno.

This library supports cosmos address generation and verification. It enables you to create an offline signature functions of different types of transaction messages. It will eventually support all the other blockchains that are based on Tendermint in the future.

⚠️ If you need for classic version for amino signing, download a version under v0.9.7

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In order to fully use this library, you need to run a local or remote full node and set up its rest server, which acts as an intermediary between the front-end and the full-node.

NPM (Protobuf)

npm install @cosmostation/cosmosjs

Yarn (Protobuf)

yarn add @cosmostation/cosmosjs

NPM (Amino)

npm install @cosmostation/cosmosjs@0.9.7

Yarn (Amino)

yarn add @cosmostation/cosmosjs@0.9.7


import { Cosmos } from "../src/index.js";


  • You need to import Cosmos-sdk Protobuf message file as js. It is created by gen-proto.sh.
  • @cosmostation/cosmosjs@0.10.0+ is running above nodejs v14+
  • You can run with this option for ES6.
$ node --es-module-specifier-resolution=node example/cosmoshub.js
  • Import the message file that is converted from Cosmos-sdk proto.
import message from "@cosmostation/cosmosjs/src/messages/proto";
  • Stargate-final: Generate Cosmos address from mnemonic
const mnemonic = "..."
const chainId = "cosmoshub-4";
const cosmos = new Cosmos(lcdUrl, chainId);

const address = cosmos.getAddress(mnemonic);

Generate both privKey and pubKeyAny that are needed for signing.

const privKey = cosmos.getECPairPriv(mnemonic);
const pubKeyAny = cosmos.getPubKeyAny(privKey);

Transfer ATOM to designated address.

  • Make sure to input proper type, account number, and sequence of the cosmos account to generate protobuf structure. You can get those account information on blockchain. Protobuf signing is different from Amino signing.
cosmos.getAccounts(address).then(data => {
	// signDoc = (1)txBody + (2)authInfo
	// ---------------------------------- (1)txBody ----------------------------------
	const msgSend = new message.cosmos.bank.v1beta1.MsgSend({
		from_address: address,
		to_address: "cosmos1jf874x5vr6wkza6ahvamck4sy4w76aq4w9c4s5",
		amount: [{ denom: "uatom", amount: String(100000) }]		// 6 decimal places (1000000 uatom = 1 ATOM)

	const msgSendAny = new message.google.protobuf.Any({
		type_url: "/cosmos.bank.v1beta1.MsgSend",
		value: message.cosmos.bank.v1beta1.MsgSend.encode(msgSend).finish()

	const txBody = new message.cosmos.tx.v1beta1.TxBody({ messages: [msgSendAny], memo: "" });

	// --------------------------------- (2)authInfo ---------------------------------
	const signerInfo = new message.cosmos.tx.v1beta1.SignerInfo({
		public_key: pubKeyAny,
		mode_info: { single: { mode: message.cosmos.tx.signing.v1beta1.SignMode.SIGN_MODE_DIRECT } },
		sequence: data.account.sequence

	const feeValue = new message.cosmos.tx.v1beta1.Fee({
		amount: [{ denom: "uatom", amount: String(5000) }],
		gas_limit: 200000

	const authInfo = new message.cosmos.tx.v1beta1.AuthInfo({ signer_infos: [signerInfo], fee: feeValue });


Sign transaction by using stdSignMsg and broadcast by using /cosmos/tx/v1beta1/txs REST API

const signedTxBytes = cosmos.sign(txBody, authInfo, data.account.account_number, privKey);
cosmos.broadcast(signedTxBytes).then(response => console.log(response));

Now it is time to transfer CW20 tokens via Cosmosjs! Copy the CW20 contract into the variable of cw20Contract. You can instantiate and execute cosmwasm contracts on JUNO. It is possible to create your own CW20 token here.

cosmos.getAccounts(address).then(data => {
	// signDoc = (1)txBody + (2)authInfo
	// ---------------------------------- (1)txBody ----------------------------------
	let cw20Contract = "juno10rktvmllvgctcmhl5vv8kl3mdksukyqf2tdveh8drpn0sppugwwqjzz30z";
	let transferBytes = new Buffer('{"transfer":{"amount":"1","recipient":"juno1cx4nq77x3unvl2xsa9fmm9drxkexzkjnzwt2y7"}}');
	const msgExecuteContract = new message.cosmwasm.wasm.v1.MsgExecuteContract({
		sender: address,
		contract: cw20Contract,
		msg: transferBytes,
		funds: []

	const msgExecuteContractAny = new message.google.protobuf.Any({
		type_url: "/cosmwasm.wasm.v1.MsgExecuteContract",
		value: message.cosmwasm.wasm.v1.MsgExecuteContract.encode(msgExecuteContract).finish()

	const txBody = new message.cosmos.tx.v1beta1.TxBody({ messages: [msgExecuteContractAny], memo: "" });

In addition, you can query CW20 token balance using wasmQuery.

	'{"balance": {"address": "juno1sautwkp7mzftvqtct3ugtq9xuuq680tzqzvf5g"}}'
).then(json => {
	let smartCode = json.result.smart;
	let decoded = new Buffer(smartCode, 'base64').toString();
	let parsed = JSON.parse(decoded);

	console.log("NETA balance: ", parsed.balance);

Official LCD url(https://api.cosmos.network).

Supporting Message Types (Updating...)

We will continue to update the protobuf signing structure.


This library is simple and easy to use. We don't have any formal documentation yet other than examples. Ask for help if our examples aren't enough to guide you


  • Contributions, suggestions, improvements, and feature requests are always welcome

When opening a PR with a minor fix, make sure to add #trivial to the title/description of said PR.

Cosmostation's Services and Community


Thanks goes to these wonderful people (emoji key):


💻 🐛 🚧


💻 📖 🚧

billy rennekamp

💻 🐛

Tony Phuong Nguyen


Tobias Schwarz


Scott Burch


billy rennekamp


Pierre Grimaud


Taariq Levack




This project follows the all-contributors specification. Contributions of any kind welcome!

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