Decentralized Application (dApp) Architecture Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Decentralized Application (dApp) Architecture flashcards as text
In a typical dApp stack, what role does the smart contract layer primarily serve?
Answer: Backend business logic and state on-chain
Smart contracts act as the on-chain backend, holding state and enforcing business logic deterministically.
Which library is most commonly used by a dApp frontend to interact with an EVM blockchain?
Answer: ethers.js
ethers.js (and web3.js) provide JavaScript APIs to read contracts and send transactions.
Why are decentralized storage systems like IPFS used in dApps instead of storing files on-chain?
Answer: On-chain storage is expensive and limited
Storing large files on-chain costs enormous gas, so dApps store data off-chain and keep only the hash on-chain.
What does a wallet like MetaMask provide to a dApp architecture?
Answer: Key management and transaction signing
Wallets manage the user's private keys and sign transactions without exposing the keys to the dApp.
Which component lets a dApp efficiently query historical and aggregated on-chain data?
Answer: An indexer like The Graph
Indexing protocols like The Graph parse events into queryable subgraphs since blockchains are poor at complex queries.
What is the purpose of an ABI in dApp architecture?
Answer: Defines how to encode/decode contract calls
The Application Binary Interface describes contract functions and types so clients can encode calls and decode results.
A 'trustless' dApp means users must trust which of the following?
Answer: The deployed contract code and chain consensus
Trustlessness comes from verifiable on-chain code and consensus rather than a trusted intermediary.