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Build Status npm version License: MIT 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.

Add dependency to your project

yarn add eosjs

Using with Typescript

In order to get access to the TextEncoding and TextDecoding types, you need to add @types/text-encoding as a dev dependency: yarn add --dev @types/text-encoding

If you're using Node (not a browser) then you'll also need to make sure the dom lib is referenced in your tsconfig.json:

	"compilerOptions": {
		"lib": [..., "dom"]

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 ESM syntax is supported using TypeScript, webpack, or Node.js with --experimental-modules flag

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


Importing using commonJS syntax is supported by Node.js 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

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 Node.js.

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


Include textDecoder and textEncoder when using in Node. You may exclude these when running in a browser since most modern browsers now natively support these. If your browser does not support these (, then you can import them as a dependency through the following deprecated npm package:

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 expireSeconds and either blocksBehind or useLastIrreversible. 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.

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