NFT Marketplace Integration 5

Question 1

When integrating a Dutch auction listing type, how does the price behave over time?

Accepted Answer

It starts high and decreases linearly until sold or reaching an end price

Answer

A Dutch auction declines from a start price toward an end price over the duration, and the first acceptable buyer wins.

Question 2

Why is reentrancy protection important in a marketplace's purchase/settlement function?

Accepted Answer

External calls during settlement could be exploited to re-enter and drain or double-spend

Answer

Settlement involves external token transfers and ETH sends, so without guards a malicious receiver could re-enter and manipulate state.

Question 3

What does the 'consideration' array represent in a Seaport order?

Accepted Answer

The items the offerer must receive for the order to be fulfilled (payments, fees, royalties)

Answer

Consideration items define everything that must be paid out—seller proceeds, marketplace fees, and royalties—when the offer is fulfilled.

Question 4

When indexing marketplace activity for a frontend, what is the most reliable data source for sale history?

Accepted Answer

Decoded on-chain events from the marketplace contract

Answer

On-chain events emitted at fulfillment are the canonical, tamper-proof record of completed sales.

Question 5

What is a key risk when integrating a marketplace that allows arbitrary external contract calls in order fulfillment?

Accepted Answer

Malicious orders could trigger phishing approvals or drain wallets

Answer

Allowing arbitrary calls during fulfillment can be abused to trick users into harmful approvals or transfers, so such flows need strict validation.

NFT Development Practice Test