What is Web3.js: Getting Started with Web3 Development

Web3.js is a collection of libraries that allow developers to interact with a remote or local Ethereum node using HTTP, IPC, or WebSocket. Using this library, you can develop websites or clients that interact with the blockchain. This can be actions like sending Ether from one user to another, checking data from smart contracts, creating smart contracts, among other things. Ethereum nodes provide interfaces to users in order to complete transactions: of which, nodes receive this information through a JSON RPC interface. This is an encoding format that allows running processes to receive new and verify existing data. Web3.js helps to make the process of running and selecting nodes participating in the Ethereum network simpler and easier to grasp.

Among the various functionalities of Web3.js, the below functions are the broadest modules that allow for interaction with the Ethereum ecosystem:

• web3-eth is for the ethereum blockchain and smart contracts.
• web3-shh is for the whisper protocol, to communicate p2p and broadcast.
• web3-bzz is for the swarm protocol, the decentralized file storage.
• web3-utils contains useful helper functions for Dapp developers.

The Web3.js library, as previously mentioned, helps developers and users alike to interact with the Ethereum blockchain network. Web3.js itself represents a JavaScript language binding for the aforementioned JSON RPC interface. This allows for the library to be inherently usable and flexible (since Javascript is natively supported in most popular web browsers), but also allows use on the server side in Node.js applications or Electron-based ones. The most common use is the one frequently stated in this piece, however: as accessing the Ethereum blockchain seems to be the chief reason that someone seeks out Web3.js. Users utilize Ethereum nodes via HTTP, which can either be locally hosted, by a Dapp (decentralized application) provider, or through public gateways like Moralis or Infura.

Generally, those creating Dapps or integrated web browser applications into the Ethereum blockchain utilize the Metamask browser extension in conjunction with Web3.js. Metamask is an Ethereum wallet that is hosted in-browser and natively puts a Web3 provider object into said browser: which, in brief, a Web3 provider object is a data-structure that provides links to publicly accessible Ethereum nodes. Using Web3.js and Metamask, users and developers are able to manage private keys and verify transactions directly from their preferred browser. If you’d like to learn more about pulling real-time transactions from the Ethereum blockchain using Web3.js, the Datastax blog team has you covered at this post here. This is among the most convenient ways of accessing the Ethereum blockchain and, generally, the preferred way for most.

Currently, there are two different versions of Web3.js that are available to any hopeful Web3 developers and crypto enthusiasts out there. The most current stable version of Web3.js is version 0.3, although its use is almost entirely eclipsed by the beta release of version 1.0. Most developers and enthusiasts have built their projects upon version 1.0, even though it is technically not an official, “stable” (so to speak) release. It is the most commonly used and accessible version, nevertheless, so the information below will reflect this.

In order to get started using Web3.js for whatever needs your project may have, you first need to obtain a copy of the library: of which there are many. Most commonly, NPM package manager is the favorite for anyone familiar with JavaScript development. Web3.js will be easily accessible via that repository, as will any assorted sub-packages you may seek out in the future for your Web3 development. Alternatively, there is Github, where you can find the Web3.js project’s repository without any hassle.

To use Web3.js to connect to the Ethereum blockchain, a programmer has to specify a Web3 provider; which is dependent on the specific node that the programmer or developer wants to connect to. Using this in conjunction with Metamask will inject a Web3 provider into the browser being used.

If you wish to interact with a smart contract, you first need the contract’s address and ABI (Application Binary Interface) to proceed. The ABI is merely a description of the contract's public interface in the form of a JSON object, which you should already be familiar with.

While the above sections highlight what is possible with the Web3.js library, real-world applications of Web3.js tend to be increasingly more complex than just merely accessing a smart contract. Generally, one must check whether a transaction they wish to do has been confirmed or not. Since Web3 is asynchronous, the time sink of getting a return is nebulous. Programmers must use callback functions frequently to be used in the event of certain criteria being met in order to keep things running smoothly. There can also be a case where the selected Web3 provider does not have access to the private key required to complete the transaction. It’s possible to send raw transactions that are already formed and signed by the corresponding private key, but these are contingency plans that must be in place ahead of time. Tracking NFT transfers are another thing possible with the application of Web3.js, but it’s even easier to do with the help of Astra DB: which you can read more about here

If you’re trying to start getting into Web3 development, Datastax AstraDB will help you build your Web3 application of the future. Built on Apache CassandraⓇ with end-to-end security, AstraDB is the powerful solution to all of your Web3 needs. Get started with AstraDB and it’s numerous features, like:

• The Ethereum Blockchain dataset has indexed every block in existence
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• Build your application through our Stargate APIs utilizing tools familiar to every developer

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