Trying to use web3-utils.

I installed the package via NPM , however, I am getting the error that sha3 is undefined..

TypeError: Cannot read property 'sha3' of undefined
    at C:\block2\deliver.js:12:28
    at Layer.handle [as handle_request] (C:\block2\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\block2\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (C:\block2\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\block2\node_modules\express\lib\router\layer.js:95:5)
    at C:\block2\node_modules\express\lib\router\index.js:281:22
    at Function.process_params (C:\block2\node_modules\express\lib\router\index.js:335:12)
    at next (C:\block2\node_modules\express\lib\router\index.js:275:10)
    at expressInit (C:\block2\node_modules\express\lib\middleware\init.js:40:5)
    at Layer.handle [as handle_request] (C:\block2\node_modules\express\lib\router\layer.js:95:5)


var express = require('express');
var app = express();
Web3 = require("web3");
web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));

var util = require('web3-utils');

app.get('/endpoint', function(request, response) {
    var id = request.query.id;

app.listen(3000, '', function() {
    console.log('Listening to port:  ' + 3000);
  • 2
    What's your web3.version? web3.utils.sha3 is available in the latest 1.0.0-betas, but not in the "release" branch, 0.20. Which version is installed by npm changed recently. Best to check. Aug 12, 2017 at 12:34
  • How can I check web3version? @benjaminion
    – alper
    Dec 29, 2017 at 21:06
  • @Alper type web3.version in the node console (after loading web3 as above). Dec 29, 2017 at 21:35

2 Answers 2


Please check your web3.js library version.

In versions < 1.0 you can call web3.sha3('test').
In 1.0 it was moved to web3.utils.sha3

Another option is to use web3-utils library, in this case you need to call utils.sha3('test').

  • I cannot do web3.utils.sha3(lengthSlot, {encoding: 'hex'}) or it just returns a different result from web3.sha3(lengthSlot, {encoding: 'hex'})
    – Ender
    Sep 16, 2019 at 8:15

Check your version by this call: web3.version.api
For versions before 1.x.x, use function from this api.
there the example of correct code.web3.toAscii

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