Blockchain Developer Decentralized Application (dApp) Architecture 3

Question 1

Why might a dApp frontend be hosted on IPFS rather than a traditional web server?

Accepted Answer

To reduce reliance on a single centralized host

Answer

Hosting the frontend on IPFS resists takedowns and aligns with the decentralization goal.

Question 2

What problem does an oracle solve in dApp architecture?

Accepted Answer

Bringing off-chain data on-chain

Answer

Oracles like Chainlink feed external data (prices, weather) to contracts that cannot access it natively.

Question 3

In a dApp, what is a common reason to use an off-chain relayer with meta-transactions?

Accepted Answer

To let users transact without paying gas directly

Answer

Relayers submit users' signed meta-transactions and pay gas, enabling gasless UX.

Question 4

Which describes the typical data flow when a user clicks 'Submit' in a dApp?

Accepted Answer

Frontend builds tx, wallet signs, node broadcasts

Answer

The frontend constructs a transaction, the wallet signs it, and a node propagates it to the network.

Question 5

What is the main architectural risk of relying on a single RPC provider like Infura?

Accepted Answer

Reintroduces a centralized dependency/outage point

Answer

A single hosted RPC endpoint becomes a centralization and availability bottleneck for the dApp.

Blockchain Practice Test