The Leading Open-Source Developer Library for Ethereum

Web3j makes it easy to build Ethereum applications with Java and Android

v4.10.3: What's changed?

What is Web3j?

Web3j is a highly modular, reactive, type safe Java and Android library for working with Smart Contracts and integrating with clients (nodes) on the Ethereum network. This allows you to work with Ethereum blockchains, without the additional overhead of having to write your own integration code for the platform.

Getting started with Web3j

Maven

Add web3j to a maven project you can include the following in your pom.xml file:


<dependency>
<groupId>org.web3j</groupId>
<artifactId>core</artifactId>
<version>4.9.1</version>
</dependency>

Gradle

For Gradle projects, you can include the following line in the dependencies section of the document:

implementation group: 'org.web3j', name: 'core', version: '4.9.1’

CLI

The CLI is bundled with great functionality aimed to smoothen the development process by providing a lot of the scaffolding required to get started. To install the CLI you will need to paste the following line on the terminal for Unix based systems:

curl -L get.web3j.io |sh

Web3j Features

Sirato integration

Web3j integrates seamlessly with the Sirato Blockchain Explorer

Type safe

Web3j provides full type safe access to your blockchain applications

Build tool integration

Plugins for leading build tools to simplify the developer experience

Versatile CLI

Create projects to work with new or import existing decentralised apps in a single command with the Web3j CLI

Powerful integration testing

Simple to use framework for automated integration testing against networks within your IDE

Commercially supported OSS

Web3j is 100% open source and maintained by Web3 Labs

Dedicated support from the creators of Web3j

Web3 Labs offer the following Web3j services

Consulting services

Strategic advisory and project delivery

Training workshops
Hands-on workshops covering blockchain and smart contract development with Web3j
Commercial support
Dedicated support for your blockchain applications