Top 10 Web3 Interview Questions

1. What is web3? The difference between web2 and web3?

web3 is the next-generation form of the Internet, which is obviously different from the current mainstream web2 form:

• web2 is centralized, and web3 is decentralized.

The web2 platform is controlled by centralized institutions, such as Facebook and WeChat. Users need to go through these centralized platforms to interact. And web3 is based on blockchain decentralization technology, users can connect and interact more freely without being restricted by a centralized platform.

• web2 pursues the maximization of benefits, and web3 pursues the maximization of value.

In order to gain more users, the web2 platform has to rely on the advertising model to make profits, which requires algorithmic recommendations to arouse user clicks and interactions, rather than content that users are really interested in. web3 focuses on allowing creators to exchange value with users directly through blockchain technology, and users can also become participants in the ecology.

• web2 users are products of the platform, and web3 users are users of the platform.

All data and attention of web2 users are collected and utilized by the platform, and users become products of the platform. While web3 users have data autonomy, users are users of the platform rather than products.

        Generally speaking, web3 represents the development trend of Internet decentralization and user decentralization, making the Internet return to the origin of direct connections between users and creators. This is an important direction for the development of Internet technology.

2. What is the difference between PoW (Proof of Work) and PoS (Proof of Stake)?

PoW (Proof of Work) and PoS (Proof of Stake) are two different consensus mechanisms in the blockchain. The main differences are:

• There are different ways to reach consensus.

PoW requires nodes to mine by solving complex computing problems, and nodes that solve problems can obtain accounting rights and system rewards. However, PoS requires nodes to lock certain assets as a deposit, and there are different probabilities of being selected to record new blocks according to the size of the deposit.

• Power consumption is different.

PoW mining requires a lot of calculations, and the power consumption and equipment costs are high. PoS only requires node-locked certificates, and the energy consumption is very low.

• There are different degrees of decentralization.

PoW relies on computing power, which can easily lead to the centralization of computing power. The deposit threshold of PoS is lower and more decentralized.

• Security is different.

PoW is more difficult to be maliciously attacked, and PoS has certain security risks.

• Ease of use is different.

PoS adopts a simpler consensus method, which is suitable for decentralized applications. PoW has a high threshold and is only suitable for high-value scenarios.

Generally speaking, PoS has higher efficiency and better scalability, and is also regarded as the development direction of blockchain. However, PoW still has unique advantages, and both mechanisms will develop in parallel.

3. What is the difference between Bitcoin and Ethereum?

As two well-known blockchain projects, Bitcoin and Ethereum have the following key differences:

• Bitcoin is an encrypted digital currency, and Ethereum is more focused on the blockchain application platform.

Bitcoin is primarily used for value storage and transactions. Ethereum provides smart contract functions that can be used to build various complex decentralized applications.

• The consensus mechanism is different.

Bitcoin uses Proof of Work (PoW), Ethereum currently uses PoW but is gradually moving to Proof of Stake (PoS).

• Programming languages ​​are different.

Bitcoin uses a simple scripting language, and Ethereum supports Solidity, a Turing-complete programming language .

• The block times are different.

The Bitcoin block time is 10 minutes, and the Ethereum target is 15 seconds. Ethereum transactions are confirmed faster.

• Circulation varies.

Bitcoin circulation has a hard upper limit of 21 million, and Ethereum has no maximum circulation limit.

• Transaction fees vary.

The gas fee of Ethereum fluctuates according to the complexity of the transaction and the degree of network congestion, while the transaction fee of Bitcoin is relatively fixed.

        Generally speaking, Ethereum is more flexible in blockchain applications, while Bitcoin is more prominent in digital gold attributes. Both have their own usage scenarios and characteristics.

4. What is a smart contract?

        A smart contract is an automated contract program running on the blockchain, which has the following characteristics :

1. The smart contract includes the rights and obligations of all parties involved in the contract, and is implemented in the form of code.

2. Smart contracts are stored and run on the blockchain network, relying on the distributed node consensus of the blockchain to execute.

3. The execution of smart contracts is automated and autonomous, and execution is automatically triggered when preset conditions are met.

4. The smart contract code and execution process are transparent and verifiable.

5. Smart contracts can handle all kinds of business logic, realize point-to-point value transfer, and can set complex conditions.

6. Smart contracts allow multiple parties to cooperate without trust.

        The main purpose of the smart contract is to make the execution of the contract independent of any intermediary agency, so as to improve the execution efficiency and reliability. Through smart contracts, blockchain can realize automated decentralized applications. Ethereum is currently the most important blockchain platform that supports smart contracts.

5. Public key and private key?

Public key and private key are a very important pair of keys in cryptography and the basis of blockchain technology.

1. The private key is a string of characters generated by random numbers, which is used to digitally sign information and must be kept secret.
2. The public key is generated from the private key and is used to verify the message. The public key can be made public and is the user's blockchain address.
3. The public key and the private key are a pair. If you know the private key, you can derive the public key, but you cannot reverse it.
4. In the blockchain, the user holds the private key to represent the ownership and control of the address. The private key is used for transaction signing.
5. Other users can use the public key to verify the validity of the signature and confirm that the initiator of the transaction has the corresponding private key.
6. If the private key is lost, the asset cannot be recovered. If the private key is leaked, assets may be stolen.
7. Therefore, the private key must be kept safe and kept secret, while the public key can be properly disclosed so that other users can interact with it.

In short, the public-private key is the cornerstone of the blockchain security mechanism and the key for each user to conduct transactions and control assets.

6. Briefly talk about what are dapp, dao, gamefi, and defi?

dapp, dao, gamefi and defi are all forms of decentralized applications based on blockchain:

• Dapp is the abbreviation of decentralized application, which runs on the blockchain through smart contracts and removes the participation of third-party centralized institutions.
• DAO is a decentralized autonomous organization, which replaces the traditional management structure through rules and smart contracts, enabling the organization to operate autonomously in a peer-to-peer manner.
• GameFi introduces the encrypted economy into the field of video games, allowing players to earn token income through games.
• Defi is decentralized finance, which realizes peer-to-peer financial services through smart contracts and removes intermediary banks and other institutions.

These applications take advantage of the immutable, transparent, and trustworthy features of the blockchain to make the provision of Internet services more autonomous and decentralized, and empower end users. They represent the trend of blockchain technology penetrating into various fields.

7. What is gas?

Gas is a key concept in Ethereum, representing the amount of computational work required to execute a transaction or smart contract. Specifically:

1. Initiating any transaction or calling smart contract functions on Ethereum requires payment of Gas fees.

2. Gas is in Gwei, and Gwei is then converted into Ethereum for payment.

3. Gas fee includes two parts: Gas Price (Gas Price) and Gas Limit (Gas Limit). The gas price determines the ether fee per unit of gas. The gas limit is the upper limit of the total amount of gas that can be paid by the transaction.

4. The actual Gas consumption of the transaction is calculated according to the transaction complexity, and the unconsumed Gas will be refunded. The gas limit is set to prevent unexpected super high fees.

5. Gas prices are determined by market dynamics and will rise when the network is congested. Users can set a higher Gas price to confirm transactions first.

6. The Gas mechanism can protect the network from being abused while providing miners with income. It also enables Ethereum to flexibly adapt to different computing workload needs.

In summary, the Gas mechanism is the key to the economic model of the Ethereum smart contract, which enables the effective allocation and utilization of network resources. It is important for users to set a reasonable Gas price and limit.

8. Can you talk about the amm mechanism in one sentence?

AMM (Automatic Market Maker Mechanism) realizes decentralized transactions without an intermediary by determining the proportional relationship of different tokens in the fund pool.

9. What apps have you played?

• Cryptocurrency wallets: such as MetaMask, used to store and transfer cryptocurrencies.
• Decentralized exchanges: such as Uniswap, use an automated market maker model for token transactions.
• NFT market: such as Opensea, used to create and trade non-homogeneous tokens.
• GameFi games: such as Axie Infinity, which integrates the mode of playing and making money.
• Decentralized social platforms: such as Lens Protocol, social applications based on blockchain.
• DeFi platforms: such as AAVE, provide decentralized lending and stable currency services.
• DAO organization: such as MakerDAO, organizes autonomous management through the blockchain.

10. What is the difference between opensea and looksrare?

Both Opensea and Looksrare are very popular NFT markets, the main differences are:

1. Opensea is one of the largest and earliest NFT markets, with the largest circulation and the best liquidity. Looksrare is an up and coming competitor.

2. Looksrare rewards users to provide liquidity for the platform and has a higher user incentive mechanism. Opensea does not.

3. Looksrare adopts the AMM model, while Opensea is more similar to a centralized exchange.

4. Looksrare has no listing fee, and Opensea needs to pay a high listing fee. 

5. Opensea's transaction volume is larger, and Looksrare's transaction volume is growing rapidly.

6. Opensea is more focused on fees, and Looksrare is more focused on community participation.

7. Opensea has a greater risk of centralization, and Looksrare has a higher degree of decentralization.

Overall, Looksrare adopts a more cutting-edge model and provides competitive alternatives, which will promote the development of the entire NFT market in a more decentralized direction. But Opensea still holds the upper hand.