10+ Blockchain Developer Interview Questions and Answers

Yes, you can publish your own custom blockchain by following these steps.

• Define the purpose and requirements of your custom blockchain

• Choose a consensus mechanism (e.g. Proof of Work, Proof of Stake)

• Select a suitable blockchain platform (e.g. Ethereum, Hyperledger)

• Develop and deploy the custom blockchain network

• Test the network for functionality and security

• Launch and promote your custom blockchain to attract users and developers

Different types of blockchains include public, private, and consortium blockchains.

• Public blockchains are open to anyone and allow for anonymous participation, examples include Bitcoin and Ethereum.

• Private blockchains are restricted to a specific group or organization, providing more control over permissions and data access.

• Consortium blockchains are semi-decentralized, where multiple organizations share the responsibility of maintaining the network, such as Hyperledger.

Different data types in blockchain development and their visibility

• Primitive data types: int, float, bool, string (visible to all)

• Structs: custom data structures (visible within the contract)

• Arrays: collection of data (visible within the contract)

• Mappings: key-value pairs (visible within the contract)

To disable transfer method in smart contracts of private blockchains, modify the contract code to remove the transfer functionality.

• Modify the smart contract code to remove the transfer method

• Update the contract's functions to restrict transfer functionality

• Implement access control mechanisms to prevent unauthorized transfers

Yes, a new blockchain can be created from scratch by defining the protocol, consensus mechanism, and network structure.

• Define the protocol for the blockchain, including the rules for block creation, validation, and transaction processing.

• Choose a consensus mechanism such as Proof of Work (PoW) or Proof of Stake (PoS) to secure the network and validate transactions.

• Design the network structure, including nodes, peers, and communication protocols.

• Implement the blockchain using ...read more

Proof of work requires miners to solve complex mathematical puzzles to validate transactions, while proof of stake selects validators based on the amount of cryptocurrency they hold.

• Proof of work involves miners solving complex mathematical puzzles to validate transactions

• Proof of stake selects validators based on the amount of cryptocurrency they hold

• Proof of work is energy-intensive and requires significant computational power

• Proof of stake is considered more energy-efficie...read more

Consensus mechanism is a process used in blockchain to achieve agreement on a single data value or a single state of the network.

• Consensus mechanisms ensure all nodes in a decentralized network agree on the validity of transactions.

• Popular consensus mechanisms include Proof of Work (PoW), Proof of Stake (PoS), Delegated Proof of Stake (DPoS), and Practical Byzantine Fault Tolerance (PBFT).

• In PoW, miners compete to solve complex mathematical puzzles to validate transactions an...read more

Gas for a transaction is estimated based on the computational resources required to execute the transaction on the blockchain network.

• Gas is a unit used to measure the computational work required to process transactions on the blockchain.

• Gas cost is determined by the complexity of the transaction and the amount of data being processed.

• Developers can estimate gas by using tools like the Ethereum Gas Station or by simulating the transaction on a test network.

• Gas prices can fluc...read more

The complete lifecycle for a blockchain transaction involves creation, validation, broadcast, inclusion in a block, and confirmation.

• Creation of transaction by sender

• Validation of transaction by network nodes

• Broadcasting of transaction to network

• Inclusion of transaction in a block by miners

• Confirmation of transaction by consensus of network nodes

Yes, I have deployed smart contracts.

• I have experience deploying smart contracts on Ethereum and Hyperledger Fabric.

• I have used Solidity and Chaincode for writing smart contracts.

• I have deployed smart contracts for supply chain management and voting systems.

• I have also tested and debugged smart contracts using Truffle and Remix IDEs.

Merkle tree is a data structure used in blockchain to efficiently verify the integrity of data.

• Merkle tree is a binary tree where each leaf node is a hash of a data block.

• Parent nodes are hashes of their respective children nodes.

• Root node is a single hash that represents the entire data structure.

• It allows for efficient verification of large data sets by only needing to check the root hash.

• Example: In a blockchain, each block contains a Merkle tree of all transactions in tha...read more

Yes, inheritance is possible in Solidity.

• Solidity supports inheritance, allowing one contract to inherit properties and methods from another.

• Inheritance is achieved using the 'is' keyword followed by the name of the base contract.

• Child contracts can access the functions and variables of the parent contract.

• Multiple inheritance is also supported in Solidity.

Code split payment method using Solidity

• Create a function in Solidity to split payment between multiple recipients

• Use the 'transfer' function to send the split payments to each recipient

• Ensure the total amount sent equals the original payment amount

I have a strong interest in blockchain technology and web3 applications.

• I have actively participated in blockchain projects and communities.

• I have experience developing smart contracts and decentralized applications.

• I stay updated on the latest trends and advancements in the blockchain space.

• I am excited about the potential of web3 to revolutionize various industries.

NFT stands for Non-Fungible Token, a unique digital asset that represents ownership of a specific item or piece of content.

• NFTs are indivisible and cannot be exchanged like cryptocurrencies.

• They are typically used to represent digital art, collectibles, virtual real estate, and more.

• Each NFT has a unique identifier that distinguishes it from other tokens of the same type.

• NFTs are stored on a blockchain, providing proof of ownership and authenticity.