Definition of Ethereum
Ethereum is an open-source, blockchain-based decentralized platform featuring smart contracts. It is a programmable blockchain that enables developers to build and deploy decentralized applications.
Unlike Bitcoin, which was originally designed mainly as peer-to-peer digital money, Ethereum was designed as a general-purpose platform. It allows developers to create many different types of blockchain applications, including but not limited to cryptocurrencies.
Open Source
Anyone can learn from, build on and contribute to the Ethereum ecosystem.
Smart Contracts
Programs that execute agreement logic on the blockchain.
DApps
Decentralized applications that run using blockchain infrastructure.
Ethereum Virtual Machine
At the core of Ethereum is the Ethereum Virtual Machine, or EVM. The EVM is the runtime environment that executes smart contracts on the Ethereum network.
Smart contract code is usually written in a high-level language such as Solidity. The code is then compiled into EVM bytecode so the Ethereum Virtual Machine can understand and execute it.
Runtime Environment
The EVM provides a standard environment for smart contracts to run across Ethereum nodes.
Bytecode Execution
Compiled smart contracts are executed as EVM bytecode.
Decentralized Applications
The Ethereum Virtual Machine makes it easier to build decentralized applications, often called dApps. Instead of creating a separate blockchain for every application, developers can build many types of applications on one shared Ethereum platform.
A dApp usually combines smart contracts with a user interface. Users interact with the application, and the smart contract logic handles transactions and state changes on the blockchain.
Smart Contract Layer
Defines the rules, state and transaction logic of the application.
User Interface Layer
Lets users connect wallets, trigger functions and view application data.
Wallet Connection
Users normally interact with dApps using wallets such as MetaMask or other Web3 wallets.
Example Idea
CryptoKitties and prototype projects such as Kittychain Shop show how digital assets can be represented in dApps.
The Ethereum Architecture
Ethereum runs on a distributed public blockchain network. Nodes connected to the network help maintain and update the blockchain state. Ethereum nodes execute smart contract instructions and help maintain consensus across the blockchain.
The Ethereum architecture allows data and value to move through a decentralized network while smart contracts define the rules for applications.
Nodes
Computers running Ethereum client software and participating in the network.
EVM
Executes smart contracts and updates blockchain state.
Consensus
Helps the network agree on the valid state of the blockchain.
Applications
DeFi, tokens, games, identity, governance and many other Web3 applications.
Consensus Update: From Proof of Work to Proof of Stake
The original article discussed Ethereum’s plan to move from Proof of Work to Proof of Stake. That transition has now happened. Ethereum completed The Merge on September 15, 2022, officially replacing Proof of Work with Proof of Stake.
Today, Ethereum no longer uses mining to produce valid blocks. Instead, validators secure the network by staking ETH and participating in Proof-of-Stake consensus.
After The Merge: Proof of Stake validation
Result: Mining replaced by staking-based consensus
This update keeps the article accurate for modern Ethereum while preserving the original article’s learning structure.
Ether and Gas Fees
Ether, often written as ETH, is the native currency of Ethereum. It is used to pay transaction fees and smart contract execution costs on the network.
Developers and users pay gas fees when they interact with Ethereum applications. Gas helps allocate network resources and prevents unlimited computation from being executed for free.
- ✓ETH is used to pay for transactions and smart contract execution.
- ✓Gas fees are paid when users interact with Ethereum applications.
- ✓Validators help secure the network under Proof of Stake.
- ✓ETH is also used in DeFi, NFTs, staking and many Web3 applications.
What Can Ethereum Be Used For?
Ethereum is more than a cryptocurrency network. It can support decentralized applications where trust, security, programmability and permanence are important.
DeFi
Decentralized exchanges, lending, borrowing, stablecoins and yield platforms.
Tokens
Fungible tokens, NFTs, utility tokens and tokenized digital assets.
Governance
DAOs, on-chain voting and transparent governance systems.
Identity
Decentralized identity and verifiable credential systems.
Supply Chain
Traceability, audit trails and multi-party coordination.
Web3 Apps
Games, marketplaces, social applications and blockchain-based services.
Ethereum is valuable because it turns blockchain from a transaction ledger into a programmable application platform.
Summary
- ✓Ethereum is an open-source programmable blockchain platform.
- ✓The Ethereum Virtual Machine executes smart contracts.
- ✓Solidity code is compiled into EVM bytecode.
- ✓Developers can build decentralized applications on Ethereum.
- ✓ETH is used to pay transaction fees and participate in the Ethereum economy.
- ✓Ethereum now uses Proof of Stake after The Merge in September 2022.