eosjs npm

Javascript API for integration with EOSIO-based blockchains using EOSIO RPC API.

Documentation can be found here



The official distribution package can be found at npm.

NodeJS Dependency

yarn add eosjs

Browser Distribution

Clone this repository locally then run yarn build-web. The browser distribution will be located in dist-web and can be directly copied into your project repository. The dist-web folder contains minified bundles ready for production, along with source mapped versions of the library for debugging. For full browser usage examples, see the documentation.


ES Modules

Importing using ES6 module syntax in the browser is supported if you have a transpiler, such as Babel.

import { Api, JsonRpc, RpcError } from 'eosjs';
import { JsSignatureProvider } from 'eosjs/dist/eosjs-jssig';           // development only


Importing using commonJS syntax is supported by NodeJS out of the box.

const { Api, JsonRpc, RpcError } = require('eosjs');
const { JsSignatureProvider } = require('eosjs/dist/eosjs-jssig');      // development only
const fetch = require('node-fetch');                                    // node only; not needed in browsers
const { TextEncoder, TextDecoder } = require('util');                   // node only; native TextEncoder/Decoder
const { TextEncoder, TextDecoder } = require('text-encoding');          // React Native, IE11, and Edge Browsers only

Basic Usage

Signature Provider

The Signature Provider holds private keys and is responsible for signing transactions.

Using the JsSignatureProvider in the browser is not secure and should only be used for development purposes. Use a secure vault outside of the context of the webpage to ensure security when signing transactions in production

const defaultPrivateKey = "5JtUScZK2XEp3g9gh7F8bwtPTRAkASmNrrftmx4AxDKD5K4zDnr"; // bob
const signatureProvider = new JsSignatureProvider([defaultPrivateKey]);


Open a connection to JSON-RPC, include fetch when on NodeJS.

const rpc = new JsonRpc('', { fetch });


Include textDecoder and textEncoder when using in Node, React Native, IE11 or Edge Browsers.

const api = new Api({ rpc, signatureProvider, textDecoder: new TextDecoder(), textEncoder: new TextEncoder() });

Sending a transaction

transact() is used to sign and push transactions onto the blockchain with an optional configuration object parameter. This parameter can override the default value of broadcast: true, and can be used to fill TAPOS fields given blocksBehind and expireSeconds. Given no configuration options, transactions are expected to be unpacked with TAPOS fields (expiration, ref_block_num, ref_block_prefix) and will automatically be broadcast onto the chain.

(async () => {
  const result = await api.transact({
    actions: [{
      account: 'eosio.token',
      name: 'transfer',
      authorization: [{
        actor: 'useraaaaaaaa',
        permission: 'active',
      data: {
        from: 'useraaaaaaaa',
        to: 'useraaaaaaab',
        quantity: '0.0001 SYS',
        memo: '',
  }, {
    blocksBehind: 3,
    expireSeconds: 30,

Error handling

use RpcError for handling RPC Errors

try {
  const result = await api.transact({
} catch (e) {
  console.log('\nCaught exception: ' + e);
  if (e instanceof RpcError)
    console.log(JSON.stringify(e.json, null, 2));


Contributing Guide

Code of Conduct




See LICENSE for copyright and license terms. Block.one makes its contribution on a voluntary basis as a member of the EOSIO community and is not responsible for ensuring the overall performance of the software or any related applications. We make no representation, warranty, guarantee or undertaking in respect of the software or any related documentation, whether expressed or implied, including but not limited to the warranties or merchantability, fitness for a particular purpose and noninfringement. In no event shall we be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or documentation or the use or other dealings in the software or documentation. Any test results or performance figures are indicative and will not reflect performance under all conditions. Any reference to any third party or third-party product, service or other resource is not an endorsement or recommendation by Block.one. We are not responsible, and disclaim any and all responsibility and liability, for your use of or reliance on any of these resources. Third-party resources may be updated, changed or terminated at any time, so the information here may be out of date or inaccurate.