Interview Questions to Ask a Blockchain Developer Before Hiring

In this article, blockchain experts at ARTJOKER have prepared good blockchain developer interview questions for you, as well as answers to them. Given the daily increase in the popularity of blockchain and the growing number of developers, you need to know what questions to ask a blockchain specialist to check his level of knowledge. If you want to hire an experienced and qualified blockchain specialist and want to assess his skills, you need to know questions to ask a blockchain developer on the interview.

General Blockchain Interview Questions

  1. What is a blockchain?

A blockchain is a decentralized, distributed and public digital ledger where encrypted blocks are stored and chained together. Blockchain records are called blocks, which are linked together using cryptography. This is one of the most popular interview questions for blockchain developer.

  1. Where is a blockchain stored?

Blockchain has two storage options, either as a flat file or as a database.

  1. What types of records are present in the blockchain database?

In a blockchain database, there are two types of records, transactional records and block records.

  1. What are blocks in blockchain technology?

This is one of the best questions for blockchain developers because real experts must have an understanding of blocks in blockchain. A blockchain consists of a growing list of records, called blocks, that are linked together using cryptography. Linked blocks form a chain of blocks called a blockchain.

  1. What is the principle behind blockchain technology?

Before you hire a dedicated blockchain developer, make sure he understands the principles of blockchain technology. The main principle of blockchain is decentralization, it aims to provide equal opportunities for everyone in the network.

  1. What is distributed ledger technology?

Basically, distributed ledger technology is a decentralized peer-to-peer digital system in which the transactions are recorded in multiple places at any given point of time. If you decide to hire a blockchain development company in the USA, make sure its developers understand distributed ledger technology. Distributed ledgers have no centralized data storage or administrator. Decentralization provides better transparency, security, and trust between the parties that use it.

  1. How can blockchain build trust?

Every blockchain developer, even a beginner, for successful blockchain application development must understand how can blockchain build trust. Blockchain is designed in such a way that no stored information can be altered or destroyed. Moreover, blockchain fosters transparency and eliminates the need for a single regulatory authority.

Technical Blockchain Interview Questions

  1. What would happen if the execution of a smart contract would cost more than the gas specified?

Before you hire blockchain developers, you need to check their knowledge of smart contracts. So let’s get to the answer. Your transaction will initially be executed, but if the execution of the smart contract will cost more than the specified gas, the miners will no longer validate your contract.

  1. What needs to be done to prevent data tampering in blockchain?

Any blockchain developer for hire must understand that all data and information in the blockchain is protected by cryptography, which means that it cannot be tampered with or altered.

  1. What is a 51% Attack?

A 51% attack, also known as a majority attack, is when a single malicious actor or group of people controls more than 50% of the network hash rate to manipulate new transactions. Before you hire blockchain app developers in the USA, make sure they understand different types of attacks on blockchain.

  1. What is a dApp?

Decentralized Applications are digital applications that built on a decentralized network and can operate autonomously, through the use of smart contracts.

  1. What is a consensus algorithm?

A consensus algorithm is a mechanism or protocol that used to achieve agreement on a single data value among distributed processes. Before you hire blockchain application developers, you need to make sure they know the consensus algorithms.

  1. What are the Merkle trees?

Merkle trees are a prevalent sort of data structure in computer science that enhance the efficiency of cryptocurrencies. Merkle trees enable fast content verification across a broad dataset.

  1. What is encryption in blockchain?

The process of blockchain encryption protects and obscures data, or networks, which makes it difficult for unauthorized parties to access. Blockchain encryption increases the security of the system and prevents sensitive information from falling into the wrong hands.


With the blockchain interview questions and answers we’ve provided in this article, you can confidently interview and check a blockchain developer’s level of knowledge before hiring. If you are looking for a competent blockchain expert, or a full-fledged development team, then ARTJOKER is ready to provide you with a full range of blockchain development services, from analysis of your idea to release and maintenance.

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