Ethereum is a blockchain network designed to do more than record cryptocurrency payments. It allows developers to create smart contracts and decentralized applications that can run without relying on one company to operate the entire system.
Its native cryptocurrency is Ether (ETH). People use ETH to pay transaction fees, participate in network staking, and interact with applications built on Ethereum.
Understanding the difference between Ethereum and ETH is important: Ethereum is the network and its underlying technology, while ETH is the asset used within that ecosystem.
How Ethereum Works
Ethereum is a distributed blockchain. Instead of storing its transaction history on one central server, the network is maintained by many independent computers called nodes.
Nodes communicate with one another and maintain copies of blockchain data. They check whether transactions follow the network's rules and help keep participants in agreement about the current state of the blockchain.
When someone sends ETH or interacts with a smart contract, the transaction is broadcast to the network. Validators process transactions and help add new blocks. Once a block is accepted, the resulting state change becomes part of Ethereum's shared record.
What nodes do
- Maintain blockchain data: Nodes store and share information about the network's history and current state.
- Verify transactions: They check whether transactions follow protocol rules.
- Support decentralization: Independent participants help prevent the network from depending on a single operator.
Not every node performs exactly the same role. Some nodes focus on verifying and sharing data, while validator nodes participate in the Proof of Stake consensus process.
Ethereum Uses Proof of Stake
Ethereum uses Proof of Stake (PoS) to organize block validation and help secure the network. Validators commit ETH as a stake and participate in proposing and attesting to blocks according to the protocol's rules.
In return for performing their duties correctly, validators can receive rewards. Validators that violate important rules or fail to meet certain responsibilities may face penalties. In some circumstances, a validator can lose part of its stake through a process called slashing.
Proof of Stake replaced Ethereum's former Proof of Work consensus mechanism in September 2022. Unlike Proof of Work, which relies on miners competing through computational work, Proof of Stake relies on validators who commit ETH.
Neither mechanism makes a network completely immune to attacks. They use different security assumptions and resource requirements. For a broader explanation, see Proof of Work vs Proof of Stake Explained Simply.
What Are Ethereum Smart Contracts?
Smart contracts are programs stored and executed on a blockchain. They follow predefined rules and can change blockchain state when users or other contracts interact with them.
For example, imagine a smart contract that allows users to exchange one token for another. Instead of asking a company employee to approve each exchange, the contract executes according to its programmed rules when the required conditions are met.
Developers commonly write Ethereum smart contracts using Solidity, a programming language designed for the Ethereum Virtual Machine (EVM).
Smart contracts support many types of applications, including:
- Decentralized finance (DeFi): Lending, borrowing, token swaps, and other financial services.
- NFT applications: Creating, transferring, and managing non-fungible tokens.
- Decentralized organizations: Systems that use tokens and contracts to coordinate proposals or voting.
- Blockchain games: Applications that use on-chain assets or rules.
Smart contracts are not automatically safe or error-free. A programming mistake, flawed economic design, or compromised external dependency can create vulnerabilities. Transactions may also be difficult or impossible to reverse once executed.
What Is ETH Used For?
ETH is the native asset of Ethereum. It has several important functions within the network.
Paying gas fees
Ethereum charges gas for transactions and smart contract operations. Gas measures the computational work required to execute an operation. Users pay for that work in ETH, with the final transaction fee depending on gas used and the applicable fee conditions.
A simple ETH transfer generally requires less computational work than interacting with a complex decentralized application. During periods of high demand, users may also face higher fees because block space is limited.
Staking
ETH can be staked to participate in Ethereum's Proof of Stake system. People who operate validators must meet the protocol's requirements, while some users participate through staking services or pooled arrangements.
Staking rewards are not guaranteed profits. Participants should understand validator requirements, service fees, withdrawal conditions, and the risks of the method they choose.
Using decentralized applications
ETH is used across the Ethereum ecosystem to pay for transactions and interact with applications. It can also be traded or held as a digital asset, although its market price can fluctuate significantly.
What Are Ethereum Gas Fees?
Gas fees compensate for the computational resources used by Ethereum transactions. A transaction's fee is influenced by the amount of gas it consumes and the fee conditions at the time it is processed.
For example, sending ETH to another address is generally a simpler operation than swapping tokens through a decentralized exchange. The swap may require several smart contract operations and therefore consume more gas.
Network demand also matters. When many users compete to have transactions included, the cost of obtaining block space can rise. A transaction that is inexpensive during a quiet period may cost more during a busy period.
Before confirming a transaction, review the wallet's fee estimate and make sure you understand the operation being approved. A high fee is not proof that a transaction is legitimate, and a low fee does not make a suspicious contract safe.
What Are Ethereum Layer 2 Networks?
Ethereum Layer 2 networks are systems built on top of Ethereum to process transactions with different performance and cost trade-offs. Many Layer 2 networks execute transactions outside Ethereum's main execution layer and use Ethereum for settlement or security-related functions.
Examples include Arbitrum, Optimism, and Base. Their designs and security assumptions differ, so users should not assume that every Layer 2 works in exactly the same way.
Layer 2 networks can offer lower transaction costs and faster user experiences for supported applications. However, users must check network compatibility, bridge arrangements, withdrawal procedures, and the security model of the specific network.
Ethereum Layer 2 networks do not make every transaction free. They have their own fees and operational considerations. Moving assets between networks can also introduce bridge and smart contract risks.
Ethereum vs Bitcoin: What Is the Difference?
Bitcoin and Ethereum are both major blockchain networks, but they were designed with different primary goals.
- Bitcoin: Primarily focuses on peer-to-peer digital money and a monetary asset with a fixed maximum supply.
- Ethereum: Provides a programmable blockchain platform for smart contracts, decentralized applications, and ETH-based transactions.
- Consensus: Bitcoin uses Proof of Work, while Ethereum uses Proof of Stake.
- Applications: Ethereum supports a broad ecosystem of smart contract applications, while Bitcoin's base protocol is more focused on secure value transfer.
These differences do not mean one network is universally better. The right choice depends on what someone wants to do and which risks, features, and trade-offs matter to them.
Important Risks and Limitations
Ethereum is a widely used blockchain, but using it still involves risks:
- Price volatility: ETH can rise or fall sharply in value.
- Smart contract vulnerabilities: Applications built on Ethereum may contain bugs or exploitable design flaws.
- Transaction irreversibility: Sending assets to the wrong address or approving a malicious transaction can lead to permanent losses.
- Network fees: Gas costs can become expensive when demand is high.
- Application and bridge risks: Third-party services and Layer 2 systems have their own security assumptions.
Final Takeaway
Ethereum is a programmable blockchain that supports ETH, smart contracts, and decentralized applications. Its Proof of Stake system coordinates validators, while Layer 2 networks extend the ecosystem with different performance and cost trade-offs. Before using an Ethereum application, understand the transaction, check the network, and review any contract permissions you are asked to approve.