What Is a Dapp? Decentralized Applications on Ethereum Explained

A dapp (decentralized application) is an application whose core logic and data run on a blockchain via smart contracts, rather than on servers controlled by a single company, typically paired with a regular web or mobile frontend that lets users interact with that on-chain logic through their wallet. The "decentralized" part refers specifically to where the application's rules and state live — on a public blockchain that no single party controls — not necessarily to how the interface itself is built or hosted.

The two-part structure of a typical dapp

Most dapps combine two distinct pieces:

1. The smart contract backend. This is the actual logic — a lending market's interest rate calculations, a DEX's swap logic, an NFT marketplace's ownership records — deployed on-chain, where it's publicly visible, executes exactly as written, and can't be unilaterally altered by any single party (barring specific, often time-locked upgrade mechanisms the contract itself defines).
2. The frontend interface. This is the website or app most users actually interact with — built with ordinary web technologies, connecting to the user's wallet, and translating clicks and form inputs into transactions sent to the underlying smart contracts.

This split matters because the frontend, unlike the smart contract, is usually not decentralized in the same sense — it's typically hosted on regular web infrastructure, controlled by the team that built it, and can be taken down, changed, or compromised independently of the underlying contracts. This is why experienced DeFi users sometimes distinguish between "the protocol" (the smart contracts, genuinely decentralized and persistent) and "the app" (the frontend, which can go offline or be phished even if the protocol itself keeps functioning) — a distinction worth understanding alongside our DeFi wallet security guide.

Categories of dapps

Category	What it does	Examples of function
Decentralized exchanges	Swap tokens directly against on-chain liquidity pools	Automated market makers, order-book DEXs
Lending and borrowing	Deposit assets to earn yield, or borrow against collateral	Covered in our DeFi lending guide
Liquid staking	Stake ETH and receive a tradeable representative token	Covered in our liquid staking guide
NFT marketplaces	Buy, sell, and mint non-fungible tokens	Covered in our NFT explainer
Stablecoin protocols	Mint or redeem tokens designed to track a stable value	Covered in our stablecoins guide
Governance / DAOs	Let token holders vote on protocol parameters and treasury decisions	On-chain proposal and voting systems

How interacting with a dapp actually works

When you use a dapp, your wallet is the bridge between you and the underlying smart contract. Typically:

1. You connect your wallet to the dapp's frontend, which reads your public address (this alone doesn't grant it access to your funds — it's read-only until you sign something).
2. The frontend constructs a proposed transaction — say, a swap or a deposit — based on your inputs.
3. Your wallet displays what you're being asked to sign or send, ideally in a structured, readable format (see our explainer on EIP-712 typed signatures for how this readability actually works under the hood).
4. You approve, your wallet signs the transaction, and it's broadcast to the network for inclusion in a block.

At no point does the dapp's frontend team custody your funds directly (in a well-designed, non-custodial dapp) — your assets move only when you sign a transaction yourself, directly interacting with the smart contract.

Why "the frontend isn't the protocol" matters

Because frontends are centrally hosted, they can be a weak point even when the underlying contracts are sound. A compromised DNS record, a hacked hosting account, or a malicious update to a frontend's code can result in users being shown a slightly different, malicious version of a normally-trustworthy interface — one that requests a malicious signature or sends funds to an attacker-controlled contract instead of the real one. This has happened to established projects' frontends more than once, which is why bookmarking known-good URLs and carefully reading what your wallet asks you to sign remain essential habits, regardless of how reputable the underlying protocol is.

Some dapps address this by supporting decentralized frontend hosting (through systems like IPFS) or by publishing verified, alternative ways to interact with the underlying contract directly — see our guide on interacting with a smart contract directly via a block explorer, bypassing the frontend entirely when needed.

Bottom line

A dapp is best understood as smart contract logic — genuinely decentralized, transparent, and persistent — paired with a conventional frontend that is usually not decentralized in the same way and can be compromised independently of the contracts it talks to. The value dapps unlock (permissionless DeFi, transparent NFT ownership, on-chain governance) comes from the smart contract layer; the practical risks users face day to day often come from the frontend layer, which is why treating the interface and the protocol as separate trust questions is a genuinely useful habit.