General purpose library for the EOS blockchain.
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Build Status NPM

Status: Alpha


General purpose library for the EOS blockchain.

Usage (read-only)

Eos = require('eosjs') // Or Eos = require('./src')

// API, note: testnet uses eosd at localhost (until there is a testnet)
eos = Eos.Testnet()

// All API methods print help when called with no-arguments.

// Next, your going to need eosd running on localhost:8888

// If a callback is not provided, a Promise is returned
eos.getBlock(1).then(result => {console.log(result)})

// Parameters can be sequential or an object
eos.getBlock({block_num_or_id: 1}).then(result => console.log(result))

// Callbacks are similar
callback = (err, res) => {err ? console.error(err) : console.log(res)}
eos.getBlock(1, callback)
eos.getBlock({block_num_or_id: 1}, callback)

// Provide an empty object or a callback if an API call has no arguments
eos.getInfo({}).then(result => {console.log(result)})

API methods and documentation are generated from:

Transaction Options

options = { expireInSeconds: 60, broadcast: true, debug: false, sign: true, scope, authorization }

  • scope {array<string>|string} - account name or names that may undergo a change in state.

    • If missing default scopes will be calculated.
    • If provided additional scopes will not be added.
    • Sorting is always performed.
  • authorization {array<auth>|auth} - identifies the signing account and permission typically in a multi-sig configuration. Authorization may be a string formatted as account@permission or an object<{account, permission}>.

    • If missing default authorizations will be calculated.
    • If provided additional authorizations will not be added.
    • Sorting is always performed (by account name).

Usage (read/write)

Eos = require('eosjs') // Or Eos = require('./src')

eos = Eos.Testnet({keyProvider: '5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3'})

// All Eos transactions as of the last update are available.  Run with no
// arguments to print usage.

// Usage with options (options are always optional)
options = {broadcast: false}
eos.transfer({from: 'inita', to: 'initb', amount: 1, memo: ''}, options)

// Object or ordered args may be used.
eos.transfer('inita', 'initb', 1, 'memo', options)

// A broadcast boolean may be provided as a shortcut for {broadcast: false}
eos.transfer('inita', 'initb', 1, '', false)

Read-write API methods and documentation are generated from this schema.

For more advanced signing, see keyProvider in the unit test.


Shorthand is available for some types such as Asset and Authority.

For example:

  • deposit: '1 EOS' is shorthand for 1.0000 EOS
  • owner: 'EOS6MRy..' is shorthand for {threshold: 1, keys: [key: 'EOS6MRy..', weight: 1]}
  • recovery: inita or inita@active is shorthand
    • {{threshold: 1, accounts: [..account: inita, permission: active, weight: 1]}}
    • inita@other would replace the permission active with other
Eos = require('eosjs') // Or Eos = require('./src')

initaPrivate = '5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3'
initaPublic = 'EOS6MRyAjQq8ud7hVNYcfnVPJqcVpscN5So8BhtHuGYqET5GDW5CV'
keyProvider = initaPrivate

eos = Eos.Testnet({keyProvider})

  creator: 'inita',
  name: 'mynewacct',
  owner: initaPublic,
  active: initaPublic,
  recovery: 'inita',
  deposit: '1 EOS'


Eos = require('eosjs') // Or Eos = require('./src')
let {ecc} = Eos.modules

initaPrivate = '5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3'

// New deterministic key for the currency account.  Only use a simple
// seedPrivate in production if you want to give away money.
currencyPrivate = ecc.seedPrivate('currency')
currencyPublic = ecc.privateToPublic(currencyPrivate)

keyProvider = [initaPrivate, currencyPrivate]

eos = Eos.Testnet({keyProvider})

  creator: 'inita',
  name: 'currency',
  owner: currencyPublic,
  active: currencyPublic,
  recovery: 'inita',
  deposit: '1 EOS'

contractDir = `${process.env.HOME}/eosio/eos/build/contracts/currency`
wast = fs.readFileSync(`${contractDir}/currency.wast`)
abi = fs.readFileSync(`${contractDir}/currency.abi`)

// Publish contract to the blockchain
eos.setcode('currency', 0, 0, wast, abi)

// eos.contract(code<string>, [options], [callback])
eos.contract('currency').then(currency => {
  // Transfer is one of the actions in currency.abi 
  currency.transfer('currency', 'inita', 10)

Atomic Operations

Blockchain level atomic operations. All will pass or fail.

Eos = require('eosjs') // Or Eos = require('./src')

keyProvider = [

testnet = Eos.Testnet({keyProvider})

// if either transfer fails, both will fail (1 transaction, 2 messages)
testnet.transaction(eos =>
    eos.transfer('inita', 'initb', 1, '')
    eos.transfer('inita', 'initc', 1, '')
    // Returning a promise is optional (but handled as expected)
  // [options],
  // [callback]

// transaction on a single contract
testnet.transaction('currency', currency => {
  currency.transfer('inita', 'initd', 1)

// mix contracts in the same transaction
testnet.transaction(['currency', 'eos'], ({currency, eos}) => {
  currency.transfer('inita', 'initd', 1)
  eos.transfer('inita', 'initd', 1, '')

// contract lookups then transactions
testnet.contract('currency').then(currency => {
  currency.transaction(tr => {
    tr.transfer('inita', 'initd', 1)
    tr.transfer('initd', 'inita', 1)
  currency.transfer('inita', 'inite', 1)

// Note, the contract method does not take an array.  Just use Await or yield
// if multiple contracts are needed outside of a transaction.

Usage (manual)

A manual transaction provides for more flexibility.

Eos = require('eosjs') // Or Eos = require('./src')

eos = Eos.Testnet({keyProvider: '5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3'})

  scope: ['inita', 'initb'],
  messages: [
      code: 'eos',
      type: 'transfer',
      authorization: [{
        account: 'inita',
        permission: 'active'
      data: {
        from: 'inita',
        to: 'initb',
        amount: 7,
        memo: ''


From time-to-time the eosjs and eosd binary format will change between releases so you may need to start eosd with the --skip-transaction-signatures parameter to get your transactions to pass.

Note, package.json has a "main" pointing to ./lib. The ./lib folder is for es2015 code built in a separate step. If your changing and testing code, import from ./src instead.

Eos = require('./src')

Use Node v8+ to package-lock.json.

Related Libraries

These libraries are exported from eosjs or may be used separately.

var {api, ecc, json, Fcbuffer} = Eos.modules


  • eosjs-api [Github, NPM]

    • Remote API to an EOS blockchain node (eosd)
    • Use this library directly if you need read-only access to the blockchain (don't need to sign transactions).
  • eosjs-ecc [Github, NPM]

    • Private Key, Public Key, Signature, AES, Encryption / Decryption
    • Validate public or private keys
    • Encrypt or decrypt with EOS compatible checksums
    • Calculate a shared secret
  • eosjs-json [Github, NPM]

    • Blockchain definitions (api method names, blockchain operations, etc)
    • Maybe used by any language that can parse json
    • Kept up-to-date
  • Fcbuffer [Github, NPM]

    • Binary serialization used by the blockchain
    • Clients sign the binary form of the transaction
    • Essential so the client knows what it is signing


git clone
cd eosjs
npm install
npm run build
# builds: ./dist/eos.js
<script src="eos.js"></script>
var eos = Eos.Testnet()


Node 6+ and browser (browserify, webpack, etc)

React Native should work, create an issue if you find a bug.