Ethereum and Smart Contracts Explained
By NorwegianSpark Editorial — written with AI assistance and reviewed by the NorwegianSpark SA editorial team | Last updated: 2026-07-18
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A smart contract is simply a program that holds rules and executes them: "if X happens, send Y to Z." This enables the broader ecosystem people talk about — decentralised finance (lending, trading without a company in the middle), NFTs, stablecoins and more, all built as contracts on top of Ethereum. Running these operations costs "gas", a fee paid in ETH that compensates the network and varies with demand; high activity means high gas, which is why fees spike during busy periods.
The honest beginner's caveat: this programmability is powerful but introduces new risks. Smart contracts can contain bugs or be outright malicious, and "the code is the law" cuts both ways — if a contract is exploited, there is often no recourse. That is why our security guide stresses caution with token approvals.
Ethereum builds on the foundations in Bitcoin basics, and it underpins much of what we discuss in stablecoins and crypto earn and staking, since ETH itself can be staked. As always, volatility and risk applies — ETH is as volatile as the rest of the market.
What "Unstoppable Code" Costs You
The property that makes smart contracts useful is the same one that makes them dangerous: they execute exactly as written, and neither party can intervene.
The practical consequences, in the order they bite:
- A bug is a feature of the contract, not an error to be corrected. Funds lost to
one are lost in accordance with the code.
- An approval is standing permission. Granting a contract access to a token usually
grants it access to your balance until you revoke it, not just for one transaction.
- Upgradeable contracts have an admin. That is often sensible engineering and it
means somebody can change the rules. Find out who, and what a change requires.
- Composability propagates failure. A contract that calls another inherits its
weaknesses, which is how single failures have cascaded across protocols.
The single most valuable habit here is reviewing and revoking token approvals periodically. Old approvals from protocols you no longer use remain live indefinitely.
Reading an Audit Correctly
An audit is a snapshot review of specific code by a specific firm, and it is routinely cited as though it were a guarantee. What to check:
| Question | Why |
|---|---|
| Which commit was audited | Deployed code is often not the audited code |
| What was in scope | Peripheral contracts are frequently excluded |
| Who performed it | Reputation in this field varies enormously |
| Were findings fixed, and re-reviewed | An audit listing unfixed criticals is a warning |
| When | Code changes; an old audit describes an old system |
An unaudited protocol is a clear risk. An audited one is a reduced risk, not an absent one — several audited protocols have failed since.
Gas, and Why Transactions Fail
Gas is payment for computation, and understanding it removes most beginner frustration:
- You pay for the attempt, not the result. A reverted transaction still consumes
gas, because the work was performed.
- The gas limit and the gas price are different things. Too low a limit causes a
failure; too low a price causes a wait.
- Costs rise with network demand, which is why the same action costs different
amounts at different times.
- Layer 2 networks exist largely to reduce this, with their own trade-offs — see
Interacting With a Contract Safely
- Verify the contract address from the protocol's official documentation, never
from a search result or a message.
- Read what the transaction actually requests in the wallet before signing.
Unlimited approvals should be a deliberate choice.
- Test with a small amount on any contract you have not used.
- Check the protocol has been live for a meaningful period with meaningful value in
it. Time is imperfect evidence and it is evidence.
- Revoke approvals you no longer need, on a schedule.
Capital at risk. Smart-contract risk is not covered by any protection scheme, and what DeFi is and whether it is safe covers the wider picture.
Understand smart contracts as automated, unstoppable code — powerful and risky in equal measure. To hold ETH or interact with contracts directly, Coinbase covers the exchange side; for the self-custody side you need a wallet whose recovery phrase you hold yourself, such as COCA. Capital at risk. This is not financial advice.
Content on AICryptoCoin is for informational purposes only and does not constitute financial advice. Always do your own research and consult a qualified financial advisor before making investment decisions.
