Book Image

Blockchain Developer's Guide

By : Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty
Book Image

Blockchain Developer's Guide

By: Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty

Overview of this book

Blockchain applications provide a single-shared ledger to eliminate trust issues involving multiple stakeholders. It is the main technical innovation of Bitcoin, where it serves as the public ledger for Bitcoin transactions. Blockchain Developer's Guide takes you through the electrifying world of blockchain technology. It begins with the basic design of a blockchain and elaborates concepts, such as Initial Coin Offerings (ICOs), tokens, smart contracts, and other related terminologies. You will then explore the components of Ethereum, such as Ether tokens, transactions, and smart contracts that you need to build simple DApps. Blockchain Developer's Guide also explains why you must specifically use Solidity for Ethereum-based projects and lets you explore different blockchains with easy-to-follow examples. You will learn a wide range of concepts - beginning with cryptography in cryptocurrencies and including ether security, mining, and smart contracts. You will learn how to use web sockets and various API services for Ethereum. By the end of this Learning Path, you will be able to build efficient decentralized applications. This Learning Path includes content from the following Packt products: • Blockchain Quick Reference by Brenn Hill, Samanyu Chopra, Paul Valencourt • Building Blockchain Projects by Narayan Prusty
Table of Contents (37 chapters)
Title Page
About Packt

Introduction to web3.js

web3.js provides us with JavaScript APIs to communicate with geth. It uses JSON-RPC internally to communicate with geth. web3.js can also communicate with any other kind of Ethereum node that supports JSON-RPC. It exposes all JSON-RPC APIs as JavaScript APIs; that is, it doesn't just support all the Ethereum-related APIs; it also supports APIs related to Whisper and Swarm.

You will learn more and more about web3.js as we build various projects, but for now, let's go through some of the most used APIs of web3.js and then we will build a frontend for our ownership smart contract using web3.js.

At the time of writing this, the latest version of web3.js is 0.16.0. We will learn everything with respect to this version.

web3.js is hosted at  and the complete documentation is hosted at

Importing web3.js

To use web3.js in Node.js, you can simply run npm install web3 inside your project directory...