Deciphr Academy
Track 1 · Module 4 · Lesson 1 of 6 · 5 min read

What is Ethereum?

Short answer

Ethereum is a blockchain with a computer built into it.1 Every node keeps a copy of that one shared computer, and anyone can offer a fee to ask it to run code.1

A request to run code + a feeThe EVMone shared stateNodekeeps a copyNodekeeps a copyNodekeeps a copyNodekeeps a copyEvery node checks the request and updates its copy
Fig. 1. Every node keeps a copy of the same computer. A request to run code is checked and carried out, and every copy updates.

A blockchain with a computer inside

A blockchain is a public database. It is updated and shared across many computers in a network.1 Those computers are called nodes.1

Ethereum adds something to this idea. It is a blockchain with a computer built into it.1 That computer is called the Ethereum Virtual Machine, or EVM. There is only one of it, and everyone on the network agrees on its current state.1

"State" means what everything looks like right now. Ethereum's state holds every account and balance, plus the data its programs keep.2

One computer, many copies

Every node keeps its own copy of this computer's state.1 Anyone on the network can send a request asking the computer to run some code. Other nodes check the request and carry it out.1 The result changes the state, and the change spreads to every copy.1

A request to run code is called a transaction request. Once it is carried out, it is a transaction.1 The record of all transactions, and the computer's current state, are stored on the blockchain.1 Once a transaction is checked and added, cryptography stops anyone tampering with it later.1

Where the idea came from

Ethereum began as a paper by Vitalik Buterin, written before the network launched in 2015.3 The paper aimed for "a blockchain with a built-in fully fledged Turing-complete programming language".4

Turing-complete means the code can, in principle, describe any calculation, even one that loops forever.4 With it, anyone could write their own rules for ownership and for transactions.4

The network went live on 30 July 2015, in a first release called Frontier.3,5 Ethereum's formal technical description is called the Yellow Paper. It names one key goal: to let people deal with each other when they would otherwise have no way to trust one another.6

Paying for the work

Ether, or ETH, is Ethereum's own currency.1 Anyone who sends a request must offer some ETH as a fee. The network burns part of it and pays the rest to whoever does the work.1

The bigger the job, the bigger the fee.1 The fee also stops people clogging the network with endless computations, because they would have to pay for every step.1

What this module covers

The next lessons look at Ethereum's two kinds of account, smart contracts, the EVM, the 2022 switch from mining to staking, and a real piece of contract code. Module 5 covers fees in more detail.

Our viewThink of Ethereum as a slow, costly computer that nobody owns and everybody can check. It is not built for heavy work. It is built for rules that many strangers need to trust.
WatchEthereum and smart contracts, in about two minutes. Captions are built in. Sources are listed at the end.
Sources
  1. Intro to Ethereum. ethereum.org developer docs, page updated 22 April 2026.
  2. Ethereum Virtual Machine (EVM). ethereum.org developer docs, page updated 26 July 2026.
  3. The history of Ethereum. ethereum.org, page updated 26 June 2026.
  4. Ethereum Whitepaper: A Next-Generation Smart Contract and Decentralized Application Platform. ethereum.org (the original paper by Vitalik Buterin).
  5. The Merge. ethereum.org roadmap, page updated 15 May 2026.
  6. Ethereum: A Secure Decentralised Generalised Transaction Ledger (the Yellow Paper), Shanghai version. Gavin Wood, Ethereum Yellow Paper, version efc5f9a, 4 February 2025.
← Module overviewNext: Accounts: people and contracts →

General education built from the publicly available sources listed above. Not financial, legal, tax or investment advice. Naming a company, project or regulator is not an endorsement either way. Last checked 2026-10-22. Terms and disclaimer.