The Ethereum Virtual Machine that runs smart contracts

A contract is "audited". What does that mean?

Experts reviewed it; risk is reduced, not removed

What happens when a smart contract contains a bug?

The code still executes as written

Ethereum & smart contracts

If Bitcoin is digital gold, Ethereum is a programmable vending machine for the world.

Explorer · 9 min · Updated 2026-11-08

💡 A vending machine nobody owns

Insert the right coins, press B4, and the machine gives you a snack — no shopkeeper needed. A smart contract is a vending machine made of code that lives on the blockchain: it follows its rules exactly, for anyone, 24/7. The catch: if the machine was built with a flaw, it will follow the flaw exactly too.

What makes Ethereum different

Bitcoin's scripting is deliberately limited. Ethereum (launched 2015) added a general-purpose computer — the Ethereum Virtual Machine (EVM) — that every node runs. Developers deploy programs (smart contracts) that hold funds and follow rules automatically.

Two kinds of accounts

Externally owned accounts — controlled by a private key (your wallet).
Contract accounts — controlled by code. They act only when called by a transaction.

What people build

Building block	Standard	Example use
Fungible tokens	ERC-20	Stablecoins like USDC, governance tokens
Non-fungible tokens	ERC-721 / ERC-1155	Tickets, collectibles, in-game items
Exchanges	AMM contracts	Swapping tokens without an order book
Lending	Over-collateralised loans	Borrowing stablecoins against ETH

Recent upgrades (for context)

Ethereum moved to Proof-of-Stake at the Merge (Sept 2022). Dencun (2024) added cheaper "blob" data for Layer 2s, Pectra (May 2025) improved wallets and staking, and Fusaka (Dec 2025) introduced PeerDAS to scale data availability further. Developers now aim for roughly two upgrades per year; check ethereum.org for the latest roadmap.

Risks unique to smart contracts

Bugs are public and permanent unless the contract was designed to be upgradeable (which adds admin-key risk).
"Audited" means reviewed, not guaranteed safe.
Approvals you sign can let contracts move your tokens.

🧮 Practical example: an escrow contract

Key takeaways

Smart contracts = code that holds funds and enforces rules.
The EVM runs on every node.
Tokens follow standards like ERC-20 and ERC-721.
Code risk and approval risk are unique dangers.

Education only — not financial advice.