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Level 1: Foundations

Ethereum Explained Simply

The programmable blockchain that powers most of crypto.

8 min read
Ethereum (ETH)
A decentralized blockchain platform that enables smart contracts and decentralized applications (dApps). While Bitcoin is digital money, Ethereum is a programmable platform where developers can build applications that run exactly as programmed.

Why It Matters

Bitcoin proved you could create digital money without banks. Ethereum took this further: what if the blockchain could run programs, not just track money?

This innovation enabled an entire ecosystem: tokens, decentralized exchanges, lending platforms, NFT marketplaces, and more — all running on code that no one can shut down or censor.

Simple Analogy

Think of Ethereum like a global computer:

  • Bitcoin is like a calculator — it does one thing (transfer value) very well
  • Ethereum is like a smartphone — it can run any app developers create
  • ETH (Ether) is the fuel that powers this computer
  • Smart contracts are the apps that run on it
  • Tokens are like items within those apps

Key Concepts

Smart Contracts

Self-executing programs stored on the blockchain. They automatically enforce agreements when conditions are met. Example: "If Alice sends 1 ETH, automatically send her 100 tokens."

Gas Fees

Every operation on Ethereum costs gas — a fee paid in ETH. More complex operations cost more gas. Fees vary based on network demand.

ERC-20 Tokens

A standard for creating tokens on Ethereum. Most tokens you hear about (USDT, LINK, UNI, SHIB) are ERC-20 tokens living on Ethereum.

Proof of Stake

In 2022, Ethereum switched from Proof of Work to Proof of Stake. Instead of mining, validators stake 32 ETH to secure the network, reducing energy use by ~99%.

Bitcoin vs Ethereum

AspectBitcoinEthereum
Primary PurposeDigital money / Store of valueProgrammable platform
Created20092015
CreatorSatoshi Nakamoto (anonymous)Vitalik Buterin (known)
SupplyFixed (21 million max)No hard cap (but deflationary)
ConsensusProof of WorkProof of Stake (since 2022)
Smart ContractsLimitedFull support
Transaction Speed~10 minutes~12 seconds

What's Built on Ethereum

DeFi (Decentralized Finance)

Lending, borrowing, trading without banks. Examples: Uniswap, Aave, Compound.

Stablecoins

Dollar-pegged tokens for stability. Most USDT and USDC live on Ethereum.

NFTs

Unique digital assets for art, collectibles, gaming items.

DAOs

Decentralized Autonomous Organizations — community-governed entities.

Main Risks
  • Gas fees: Can be very high during network congestion ($50+ per transaction)
  • Smart contract bugs: Code errors can lead to fund losses
  • Complexity: More moving parts = more potential failure points
  • Regulatory uncertainty: DeFi and tokens face unclear legal status
  • Competition: Other platforms (Solana, Avalanche) compete for users
What Beginners Should Remember
  • Ethereum is a platform; ETH is its native currency used for gas fees
  • Most tokens and DeFi projects run on Ethereum
  • You need ETH to interact with anything on Ethereum (even to send tokens)
  • Layer 2 solutions (Arbitrum, Optimism) offer cheaper transactions
  • Don't interact with smart contracts until you understand the risks