What Is Ethereum? A Beginner's Guide

Bitcoin set out to be money, Ethereum wanted to be a computer: one that anyone on earth can run code on, that nobody owns, and that no one can switch off. It sounds abstract, and it is not: nearly every crypto thing you have half-heard about that is not Bitcoin, the trading apps, the million-dollar JPEGs, the dollar tokens moving billions a day, sits on Ethereum or on something cloned from it.

It began as a teenager's complaint: Vitalik Buterin was nineteen, and he liked Bitcoin but thought it was hobbled, able to move a coin from A to B and not much else. In late 2013 he wrote a whitepaper proposing something far more open-ended. A few others came aboard, Gavin Wood and Joseph Lubin among them. They sold ether for Bitcoin in a 2014 crowdsale to fund the build, and the network went live on 30 July 2015. Bitcoin tracks who owns what, Ethereum tracks who owns what and also runs programs, and that second half is the whole story.

The blockchain underneath it

Ethereum runs on a blockchain, the same trick Bitcoin uses: a shared record of transactions, copied across thousands of machines, new entries bundled into blocks and chained to the last. No master copy on a server: rewrite an old entry and you would have to outmuscle the entire network at once, which is what makes the thing hard to fake. Bitcoin mostly uses its chain to move coins between addresses. Ethereum uses its to move coins and to run code, and the people keeping all those copies in step get paid for it.

The coin is ether, ticker ETH, and anything that is not Bitcoin gets lumped together as an altcoin, with ether the biggest of them by a country mile, usually the second most valuable crypto behind Bitcoin full stop. Here is the bit newcomers miss: ether is not just a thing you buy and pray goes up, it is fuel. No ether, no moves. You cannot send a token or touch an app on Ethereum without a little of it in the tank.

Smart contracts, in plain words

The programs are called smart contracts, a grander name than they deserve. A smart contract is code that runs exactly as written, on its own, with no company in the middle to nod it through or change its mind. Think of a vending machine: right coins in, can of drink out, no shopkeeper. Apply that to money and agreements and you have the idea: lend, swap, insure, mint a token, run a game. Write the rules and the network enforces them, the same way for everyone, at 4am, with nobody deciding whether you are worthy.

Take Uniswap, one of the better-known apps: it swaps one token for another, and there is no firm taking your order in the back room. Price, trade, settlement, all handled by a contract you can read line by line if you fancy it. Connect a wallet, approve, pay the fee, done in seconds. The same machinery runs the lending apps where you borrow against your crypto. None of them ask your name.

Lovely on paper, and in practice it cuts both ways, hard. Because the code runs by itself, strangers who will never meet can move money between them without trust. And because the code runs by itself, a bug in that code runs too, and nobody can reach in and stop it once it is live. Hold both halves of that sentence in your head, because the history below is what happens when you forget the second one.

Tokens: the stuff built on top

Most coins people trade are not their own blockchains at all, they are tokens issued on Ethereum using a shared format called the ERC-20 standard, hammered out back in 2015, which lets any wallet or exchange handle a new token without custom plumbing. That is why thousands of coins behave alike and drop into the same apps. Stablecoins, governance tokens, the decent projects and the outright junk, a vast number of them are just ERC-20 tokens riding Ethereum's rails. Worth knowing, because when you hold one you still need a little ether to move it. The fee is always paid in ether, never in the token.

Gas fees: paying for the shared computer

Running code on a computer the whole planet shares is not free, and that cost is the gas fee. Every action, sending ether, using an app, minting a token, costs a fee in ether, paid to whoever is keeping the lights on. The price floats, tracking demand, because everyone is bidding for the same scarce room in each block. In a quiet hour an ordinary transfer might run a few pence, and during a frenzy it has spiked into the tens of pounds for one click.

None of that is hypothetical: through the 2020 and 2021 boom, when a flood of trading apps and art sales swamped the network, the average transfer fee blew past 50 dollars on the worst days, and fiddly actions cost a good deal more. People paid more in fees than the thing they were buying was worth. That is the loudest complaint Ethereum gets, and it is the reason a whole layer of cheaper networks now sits on top to take the strain, which I will come back to. A 2021 change called EIP-1559 also reworked how fees are set and started burning a slice of every one, taking that ether out of circulation for good.

The history that shaped it

Two events tell you most of what you need about how Ethereum behaves, so learn them before you buy any. The first is The DAO: in 2016, barely a year after launch, a flagship project of that name raised around 150 million dollars of ether from thousands of people. The pitch: an investment fund run entirely by code, no managers, no suits. Then an attacker spotted a flaw and started draining it, siphoning off roughly 60 million dollars. The community froze: do nothing and honour the principle that the code is final, or step in and grab the money back.

They stepped in. The network was rewound to undo the theft, and the row over it was so bitter that a stubborn minority refused on principle and kept the original, untouched chain alive. That fork is still around today as Ethereum Classic, its own coin with its own crowd, trading years later. A blunt lesson: "code is law" gets awkward the second the code has a bug, and it forced an early, uncomfortable question about who really runs a network that is meant to be run by no one.

The second is The Merge: for its first seven years Ethereum secured itself the way Bitcoin still does, through mining, with machines racing to crack puzzles and burning electricity to do it. Critics battered the network for years over the power bill. The Merge switched mining off and swapped in staking, where holders lock up ether to validate transactions and earn rewards rather than burning power. It happened on 15 September 2022, after delay upon delay, and the network did not miss a beat: energy use fell by about 99.9% overnight. To validate solo you need 32 ether, which is a lot, so most stakers go through pools or exchanges and join with far less. A follow-up upgrade in April 2023, Shapella, finally let stakers pull out the ether they had locked, shutting a gap that had nagged at people. The security maths shifted too: under mining an attacker needed raw computing power. Under staking they would need to own and risk a huge pile of ether, and any cheating gets that pile destroyed, a punishment the network calls slashing. Different threat, same logic: attacking Ethereum should cost you more than you could ever steal.

What actually runs on Ethereum

It helps to see what it is for, and four broad things sit on top. Decentralised finance, DeFi for short, rebuilds lending, borrowing and trading with smart contracts instead of banks, and at its late-2021 peak held over 100 billion dollars of crypto. Non-fungible tokens, NFTs, use the network to prove who owns a given digital item, which is how a single collage by the artist Beeple went for 69 million dollars at Christie's in March 2021. Stablecoins, coins pinned to a dollar, mostly live here and shift billions a day, routinely dwarfing ether's own volume. And layer-2 networks, names like Arbitrum, Optimism and Base, bundle transactions cheaply elsewhere then settle them back on Ethereum, which is how the network is coping with the fee mess instead of pricing ordinary people out.

You do not need any of that to own ether. But it is why ether is worth anything beyond a punt: people need it to pay for all of the above, and the busier it gets, the more of it those activities eat.

Wallets and addresses, briefly

To hold ether or use anything here you need a wallet. A wallet does not store coins, the coins live on the blockchain: it holds the keys that prove the coins are yours and let you spend them. Each wallet has a public address, a long string starting "0x", which you hand out to receive funds, and a private key or recovery phrase, which you guard like your life depends on it, because whoever holds it holds the money. One nice thing: the same wallet works across the lot. A single address can hold ether, a dozen tokens and an NFT at once, and click into apps. Lose the recovery phrase and the access is gone for good, no support line resets it. Full control in exchange for full responsibility, and it catches people out constantly.

Ethereum is not "better" than Bitcoin, it is different

People love staging these two as rivals, but they are barely going for the same job. Bitcoin wants to be the soundest possible digital money: deliberately plain, hard to change, capped at 21 million coins ever. Ethereum trades some of that restraint for flexibility, and flexibility means more moving parts and more ways to come unstuck. One is a vault, the other is a workshop. You judge a vault on how little it changes and a workshop on how much it lets you build. Plenty of people hold both, for exactly those opposite reasons, and there is nothing odd about that. The mistake is treating "which wins" as if they were racing to one finish line. They are not.

The honest risks

Ether is volatile: it topped out near 4,800 dollars in November 2021, then sank under 1,000 by mid-2022, a fall of roughly 80%, before clawing back over the years since. That swing is the norm for it, not a freak event, and you have to be able to stomach it. Past price, the platform carries risks Bitcoin mostly sidesteps. Smart contracts get exploited, as The DAO showed and as fresh hacks prove most years, hundreds of millions drained from buggy or malicious apps. The network keeps changing through upgrades, a strength for builders and a headache for everyone wanting a quiet life. And the wider ecosystem is stuffed with junk tokens trading on Ethereum's name, some flat-out scams. None of which means avoid it, it means know what you are holding, and treat anything promising effortless riches with deep suspicion.

How to buy a little

Buying ether works like buying any crypto: through an on-ramp that turns your money into ETH and sends it to your wallet or account. A fraction is fine, you never need a whole coin, and ether splits into tiny units, so a few pounds buys a sliver. Sensible opening amount is one you would not miss if it halved, because it can and it has. Once you hold some you can leave it be, send it to a wallet you control, or use it across the apps above, though that last bit is for later, not day one. For the full walkthrough, read how to buy crypto for the first time, and for the foundations under all of this, start with what Bitcoin is. This is a beginner's guide and an educational explainer, not financial advice.