Top 10 Frequently Asked Interview Questions for Blockchain Developer with Answers

As blockchain technology continues to disrupt industries and gain widespread adoption, the demand for skilled blockchain developers has skyrocketed. Companies across a wide range of industries are looking for talented individuals with expertise in designing, developing, and deploying blockchain solutions. If you are looking to apply for a blockchain developer position, it is important to be well prepared for the interview process. In this article, BlockchainWork will help you compile the Top 10 frequently asked blockchain developer interview questions and attach sample answers for your reference.

What exactly is the role of a blockchain developer?

The job of blockchain developers is to create, test, and program blockchain software and systems. They are divided into two types:

• Core Blockchain Developer: They create and maintain the blockchain system architecture. They also create protocols, security templates, and manage the entire network.
• Blockchain Software Developer: These individuals create blockchain applications on top of existing blockchain platforms. They are responsible for developing, maintaining, and troubleshooting these applications.

Qualification to become a blockchain developer

• Understand how blockchain works in practice.
• Learn about failure points and develop overall system security skills.
• A basic understanding of how cryptography works will be helpful when developing blockchain code.
• Proficient in multiple programming languages ​​such as Python, Ruby, C++, Java, JavaScript, Go, Rust, etc.
• A background in web development, networking and security would be beneficial.

>>See more: Latest blockchain jobs in Vietnam

Top 10 Frequently Asked Interview Questions for Blockchain Developer

1. What is blockchain technology and how is it different from traditional databases?

Blockchain technology is a decentralized and distributed ledger system that allows multiple participants to maintain and update a shared database without the need for a third party to manage it. It consists of a chain of blocks, each of which contains a list of transactions or data. A key difference from traditional databases is that blockchain uses cryptographic techniques to ensure the immutability and integrity of data. Additionally, blockchain provides trust and transparency by allowing participants to independently validate and verify transactions, eliminating the need for intermediaries.

2. Why is blockchain called “secure and sustainable”?

Blockchain is considered “secure and sustainable” because data is stored in a decentralized manner, reducing the risk of attacks on a single point. Transactions are encrypted and linked using hash functions, making data tampering nearly impossible. Consensus mechanisms like Proof of Work or Proof of Stake ensure that only valid transactions are recorded. Once data is written to the blockchain, it cannot be altered, maintaining integrity and transparency. Additionally, blockchain is highly fault-tolerant, ensuring continuous operation and long-term data storage. 

>>See more: Vietnam’s Blockchain Adoption Ranking and Tech Talent Quality

3. Name the different types of blockchain? 

Public Blockchain

Anyone can read and write data on the blockchain, and this validation process requires thousands or tens of thousands of nodes to participate. However, it has several disadvantages including high computing power and lack of transaction privacy. These are important factors to consider when using public blockchains in a business environment.

Private Blockchain

Unlike Public Blockchain, Private Blockchain is a peer-to-peer network with a central point of control. Because here participants need to have approval to join the network. Transactions are private and only those ecosystem participants who have been granted permission to join the network can make transactions. So this can be a powerful tool for businesses.

Blockchain Consortium

This is a combination of Public Blockchain and Private Blockchain, where there will be a small number of parties with equal rights acting as validators. Using Consortium Blockchain is the best option for businesses that want all partners to have access to the blockchain and share responsibility among them.

>>See more: Is Your Blockchain Job Safe? Expert Tips to Cope with the Unemployment Wave


4. How does cryptography in blockchain technology ensure security and privacy?

• Secure transactions: Cryptographic techniques such as digital signatures ensure the authenticity and integrity of transactions, preventing unauthorized modifications.
• Privacy protection: Techniques such as asymmetric (public key) encryption and zero-knowledge proofs allow participants to maintain privacy by selectively sharing information while keeping other data secret.
• Immutable Records: Cryptographic hash functions ensure the immutability of blocks and transactions, making it computationally infeasible to tamper with the blockchain’s history.
• Secure key management: encryption is used to generate, store, and manage secure keys, protecting private keys from unauthorized access.

5. What are the popular platforms for building blockchain applications?

Many platforms have entered the market due to the increasing popularity of blockchain technology. In fact, these platforms allow the building of applications and solutions using cryptocurrencies. Some of the popular platforms are Ethereum, Hyperledger, Qtum, EOSIO, and IOTA.

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6. What are the main components of a transaction in a blockchain system?

• Sender: The address or identifier of the entity initiating the transaction.
• Recipient: The address or identifier of the entity receiving the transaction.
• Amount: The amount of digital asset or currency being transferred.
• Transaction hash: A unique identifier created by hashing transaction data.
• Digital Signature: A cryptographic signature created using the sender’s private key to verify the authenticity and integrity of a transaction.
• Timestamp: The time a transaction was created or included in a block.

7. Explain the concept of smart contract and its role in blockchain applications.

A smart contract is a self-executing contract with the terms of the agreement written directly into the code. It is stored and executed on a blockchain network. Smart contracts facilitate the automation and execution of agreements without relying on intermediaries. They allow parties to interact and transact with each other in a transparent and secure manner. Smart contracts can be used for a variety of applications, including financial services, supply chain management, decentralized applications ( DApps ), and more.

8. Describe the process of adding a new block to the blockchain?

• Transactions are collected and grouped into a block.
• Miners or validators compete to solve a complex mathematical puzzle by performing computational work or selected based on particular consensus conditions.
• The first miner to solve the puzzle broadcasts the solution, along with the new block and its transactions, to the network.
• Other nodes in the network verify the block’s transactions and the puzzle’s solution.
• Once the block is verified and accepted by the network, it is added to the blockchain and becomes an unchangeable part of history.

9. What consensus mechanisms operate in blockchain networks, and what are the common consensus mechanisms?

Consensus in a blockchain network is the process by which participants agree on the state of the blockchain and validate transactions. It ensures that all nodes reach a common consensus on the order and validity of transactions. Common consensus mechanisms include:

• Proof of Work ( PoW ): Miners compete to solve a computationally intensive puzzle and the first to find the solution adds the next block. Used by Bitcoin and Ethereum.
• Proof of Stake ( PoS ): Validators are selected to create new blocks based on the amount of cryptocurrency they hold, or “stake.” It reduces the need for computational work and energy consumption. Used by networks like Cardano and Ethereum 2.0.
• Delegated Proof of Stake ( DPoS ): Token holders vote for a group of delegates to validate transactions and create new blocks. It provides faster transaction processing and is used by networks like EOS and TRON.
• Practical Byzantine Fault Tolerance (PBFT): Participants called “validators” reach consensus through multiple rounds of voting. It achieves high throughput and is used by permissioned blockchains like Hyperledger Fabric.

10. Are you familiar with Token standards, such as ERC-20 and ERC-721? Explain their purpose and the difference between them?

• ERC-20: ERC-20 is a standard for fungible tokens, meaning each token is identical and interchangeable. It allows for the creation of cryptocurrencies or tokens that can be used for a variety of purposes, such as digital assets or utility tokens.
• ERC-721: ERC-721 is the standard for non-fungible tokens (NFTs). Unlike ERC-20, each token is unique and represents ownership of a separate asset. NFTs are often used for digital collectibles, works of art, or unique assets in decentralized applications.

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Conclusion

Above, BlockchainWork has compiled for you common interview questions for blockchain developer positions. Although there are other questions outside the list, careful preparation and confidence in the interview will help you achieve good results. Don’t forget to visit BlockchainWork’s website to update more useful information and increase your chances of success!

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References:

Best 26 Blockchain Developer Interview Questions And Answers . (nd). Web3 Jobs.

Roadmap to Become a Blockchain Developer in 2023 – The Workfall Blog . (2023, January 10). Workfall.

Sharma, TK (2022, July 13). Top 15 Blockchain Developer Interview Questions and Answers . Blockchain Council.

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