Web3 is a JavaScript library that can be used to communicate with an Ethereum node via RPC communication.
Web3 works by exposing methods that have been enabled over RPC.
Building Decentralized Applications from Scratch (Part 2)
This allows the development of user interfaces that make use of the Web3 library in order to interact with the contracts deployed over the blockchain.
In order to expose the methods via geth, the following command can be used: $ geth –datadir .ethereum/privatenet/ –networkid 786 –rpc –rpcapi ‘web3,net,eth,debug’ –rpcport 8001 –rpccorsdomain ‘http://localhost:7777’ The –rpcapi flag allows the web3, eth, net, and debug methods.
This is a powerful library and can be explored further by attaching a geth instance.
section, the concepts and techniques of making use of Web3 via JavaScript/HTML frontends.
The geth instance can be attached using the following command: $ geth attach ipc: ~/etherprivate/geth.ipc Once the geth JavaScript console is running, Web3 can be queried, for example: Web3 via geth
Why This Matters for Blockchain Technology
Understanding Web3 is not just an academic exercise — it has real-world implications for how blockchain systems are designed, deployed, and secured. Whether you are a developer building decentralized applications, a business leader evaluating blockchain adoption, or a curious learner exploring the technology, this knowledge provides a critical foundation.
Key Points to Remember
- Web3 Web3 is a JavaScript library that can be used to communicate with an Ethereum node via RPC communication.
- Web3 works by exposing methods that have been enabled over RPC.
- This allows the development of user interfaces that make use of the Web3 library in order to interact with the contracts deployed over the blockchain.
- In order to expose the methods via geth, the following command can be used: $ geth –datadir .ethereum/privatenet/ –networkid 786 –rpc –rpcapi ‘web3,net,eth,debug’ –rpcport 8001 –rpccorsdomain ‘http://localhost:7777’ The –rpcapi flag allows the web3, eth, net, and debug methods.
Conclusion
Web3 represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.