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About the test:

The Blockchain Developer Online Test uses scenario-based multiple choice questions to evaluate candidates on their technical knowledge and practical skills related to blockchain development, covering topics such as blockchain architecture, consensus algorithms, smart contracts, cryptocurrency, token economics, decentralized applications (dApps), and blockchain security. The test aims to determine candidates' ability to build innovative blockchain solutions that solve real-world problems and meet business needs.

Covered skills:

  • Blockchain Basics
  • Decentralized Applications
  • Blockchain Security
  • Distributed Ledger Technology
  • Blockchain Development Tools
  • Blockchain Integration
  • Smart Contracts
  • Cryptocurrency
  • Consensus Mechanisms
  • Blockchain Platforms
  • Tokenization
  • Blockchain Scalability

9 reasons why
9 reasons why

Adaface Blockchain Developer Assessment Test is the most accurate way to shortlist Blockchain Developers

Reason #1

Tests for on-the-job skills

The Blockchain Developer Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

  • Understanding the basics of blockchain technology
  • Building and deploying smart contracts
  • Developing decentralized applications on blockchain platforms
  • Understanding the concepts of cryptocurrencies
  • Implementing security measures in blockchain applications
  • Knowledge of various consensus mechanisms
  • Understanding distributed ledger technology
  • Working with different blockchain platforms
  • Using blockchain development tools effectively
  • Understanding the process of tokenization
  • Integrating blockchain into existing systems
  • Managing scalability challenges in blockchain development
Reason #2

No trick questions

no trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

View sample questions

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface
Reason #3

Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

How we design questions

These are just a small sample from our library of 10,000+ questions. The actual questions on this Blockchain Developer Test will be non-googleable.

🧐 Question


51% Attacks
A 51% attack is perhaps the most discussed threat to any public Blockchain asset. A 51% attack happens when a certain miner or mining pool, that owns more than 50% of all the network’s hashing power, acts maliciously to disturb the network’s operation.
For example: Two Bitcoin Cash mining pools, carried out a 51% attack on the Bitcoin Cash blockchain in order to stop an unknown miner from taking coins that they weren’t supposed to have access to, while the network forked.
Which of the following CAN be done by a miner employing a 51% attack?

A: Double spend their coins
B: Reverse confirmed transactions
C: Steal funds from a certain address
D: Prevent transactions from being confirmed
E: Create false transactions that never happened


Breed Chasing, solo engineer is planning to create new cryptocurrency, NEWCRAIGLIST and build a blockchain that facilitates buying and selling second-hand items with NEWCRAIGLIST from each other. Breed expects the platform to be used for international transactions and devised the following process:

- Before a transaction is considered complete, the purchaser must put the funds in an escrow service
- The sender must enter the courier tracking number into that same escrow
Palmart, toy store giant in US is asked by lawmakers to provide evidence that proves the store’s toys are not produced through child labour. Palmart’s toys are transferred between 7 parties between creation and placement at the store. Palmart is considering using blockchain to solve this problem. Discretion in the reading and writing of transactions is highly important to the store chain to protect its proprietary interests. Review the following possible solutions and pick the best approach that solves Palmart’s problem:
Option A:
Use a public blockchain that supports assets.
Then create a new toy asset for each item created. 
When the toy is transferred to the next party, mandate that the associated blockchain asset to be transferred to the next party's blockchain account with required metadata.
Lawmakers can now view transactions and transfers at any time.

Option B: 
Use a permissioned blockchain.
Require that every party involved in the process to host a node on the Palmart's network. 
Create a new toy asset for each item created. 
When the toy is transferred to the next party in the process, have the previous party use a web portal to initialize a chain code Smart Contract to transfer control of the asset. 
When the next party receives the asset have them use a web portal to initialize a chain code Smart Contracts to acknowledge receipt of the asset. 
Provide read-only permissions to the lawmakers so they can receive the evidence they are looking for.


Blockchain Interoperability
Smart Contract Logic
Decentralized Applications
Consider a blockchain ecosystem where a decentralized application (dApp) is designed to operate across two different blockchains: Blockchain A, which uses a unique smart contract language and execution environment, and Blockchain B, which supports Ethereum Virtual Machine (EVM) compatible smart contracts. The dApp includes a cross-chain functionality where certain actions triggered in Blockchain A's smart contract result in specific operations in a smart contract on Blockchain B. The interoperability is facilitated through a decentralized oracle that verifies and relays information between the two blockchains. Given this setup, which of the following statements most accurately reflects the challenges and considerations in implementing this dApp's cross-chain functionality?
A: Cross-chain functionality cannot be achieved due to the different smart contract languages and execution environments.
B: The decentralized oracle introduces a single point of failure, compromising the security of the dApp.
C: Synchronizing state between the two blockchains is seamless and does not introduce any additional latency.
D: The dApp can maintain consistency and atomicity in transactions across the blockchains, but it faces challenges in data validation and oracle reliability.
E: Smart contract execution on Blockchain B is entirely dependent on the state of the smart contract on Blockchain A.
F: The interoperability poses no significant challenges, as EVM compatibility ensures seamless cross-chain communication.


Strategic Tokenomics
Cryptocurrency Economics
A new cryptocurrency, CryptoX, has a fixed total supply of 100 million tokens. Its initial release of 40 million tokens is distributed as follows: 10 million for development, 15 million for a decentralized autonomous organization (DAO) treasury, and 15 million for staking rewards. The remaining 60 million tokens are locked, with a scheduled release decreasing by 10% each year. CryptoX also has a deflationary mechanism where 0.1% of each transaction is burned.

During a market downturn, CryptoX's price drops by 30% in a month. Market analysis attributes this drop primarily to increased token selling by short-term holders, influenced by a broader market downturn in cryptocurrencies. CryptoX's community is considering responses to stabilize the price and reassure long-term investors. Two strategies are proposed:

1) Increase the transaction burn rate to 0.2%, hoping to reduce the circulating supply faster and create a deflationary pressure.
2) Maintain the current tokenomics, believing that the downturn is part of normal market fluctuations and that the existing mechanisms are robust enough for long-term stability.

Given the market analysis and the nature of the downturn, which strategy is more likely to effectively stabilize CryptoX’s price while maintaining long-term value?
A: Increase the transaction burn rate to 0.2%.
B: Maintain the current tokenomics without any changes.
C: Temporarily suspend the transaction burn mechanism.
D: Increase the release rate of the locked tokens.
E: Implement a dynamic burn rate that adjusts with market conditions.
F: Introduce a temporary buyback and burn program.
🧐 Question🔧 Skill


51% Attacks

3 mins




3 mins



Blockchain Interoperability
Smart Contract Logic
Decentralized Applications

3 mins



Strategic Tokenomics
Cryptocurrency Economics

2 mins

🧐 Question🔧 Skill💪 Difficulty⌛ Time
51% Attacks
Medium3 mins
Easy3 mins
Blockchain Interoperability
Smart Contract Logic
Decentralized Applications
Medium3 mins
Strategic Tokenomics
Cryptocurrency Economics
Medium2 mins
Reason #4

1200+ customers in 75 countries

customers in 75 countries

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment Blockchain Developer Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Science behind Adaface tests
Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the Blockchain Developer Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

invite candidates
Reason #7

Detailed scorecards & benchmarks

View sample scorecard
Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

test completion rate
Reason #9

Advanced Proctoring

Learn more

About the Blockchain Developer Online Test

Why you should use Pre-employment Blockchain Developer Test?

The Blockchain Developer Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

  • Understanding and implementing blockchain basics
  • Writing and deploying smart contracts
  • Building decentralized applications (DApps)
  • Knowledge of various cryptocurrencies and their functionalities
  • Ensuring blockchain security measures are in place
  • Understanding different consensus mechanisms
  • Working with distributed ledger technology
  • Familiarity with different blockchain platforms
  • Utilizing blockchain development tools
  • Creating and managing tokenization mechanisms

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the Blockchain Developer Test?

  • Blockchain Basics

    Blockchain basics refer to the fundamental concepts and principles of blockchain technology, such as distributed ledger, decentralization, and immutability. This skill is measured in the test to gauge the candidates' understanding of the core foundations of blockchain before diving into more advanced topics.

  • Smart Contracts

    Smart contracts are self-executing contracts with predefined conditions written in code, which automatically enforce the terms of the agreement. Testing this skill in the assessment ensures that the candidates possess the necessary knowledge to develop and deploy smart contracts on a blockchain network.

  • Decentralized Applications

    Decentralized applications (DApps) are applications that run on a peer-to-peer network of computers instead of a central server. Testing this skill helps recruiters assess the candidates' ability to design, develop, and deploy decentralized applications using blockchain technology.

  • Cryptocurrency

    Cryptocurrency refers to digital or virtual currencies that use cryptography for security and operate independently of a central bank. Including this skill in the test allows recruiters to evaluate the candidates' understanding of cryptocurrency concepts, such as blockchain-based currencies, wallets, transactions, and mining.

  • Blockchain Security

    Blockchain security involves protecting blockchain networks and applications from various threats such as hacking, data breaches, and malicious activities. Assessing this skill helps recruiters identify candidates who are knowledgeable about security best practices within the blockchain ecosystem.

  • Consensus Mechanisms

    Consensus mechanisms determine how participants in a blockchain network agree on the validity of transactions and maintain the integrity of the ledger. Measuring this skill in the assessment ensures that candidates have a comprehensive understanding of different consensus algorithms, such as Proof of Work (PoW) and Proof of Stake (PoS).

  • Distributed Ledger Technology

    Distributed ledger technology (DLT) is the underlying technology of blockchain that enables the decentralized and transparent storage of data across multiple nodes. Assessing this skill allows recruiters to assess the candidates' understanding of the fundamental principles and implementation of DLT in blockchain systems.

  • Blockchain Platforms

    Blockchain platforms are software frameworks or infrastructures that provide the necessary tools and functionalities for building and deploying blockchain applications. Including this skill in the test helps recruiters evaluate candidates' knowledge of popular blockchain platforms like Ethereum, Hyperledger, and Corda.

  • Blockchain Development Tools

    Blockchain development tools are software applications and libraries that facilitate the creation, testing, and deployment of blockchain-based applications. Measuring this skill allows recruiters to assess the candidates' familiarity with tools such as Solidity (for Ethereum smart contract development) and Truffle (for blockchain development and testing).

  • Tokenization

    Tokenization refers to the process of converting real-world assets or rights into digital tokens on a blockchain. Testing this skill helps recruiters evaluate the candidates' understanding of tokenization concepts, token standards like ERC-20, and the integration of tokens within blockchain applications.

  • Blockchain Integration

    Blockchain integration involves connecting existing systems and applications with blockchain networks to leverage the benefits of decentralized, transparent, and secure data storage and transactions. Assessing this skill helps recruiters identify candidates who can effectively integrate blockchain technology into various industries and use cases.

  • Blockchain Scalability

    Blockchain scalability refers to the ability of a blockchain network to handle increasing transaction volumes and user demands without compromising performance and efficiency. Testing this skill in the assessment allows recruiters to evaluate the candidates' knowledge of scalability solutions like sharding, layer 2 protocols, and off-chain transactions.

  • Full list of covered topics

    The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for Blockchain Developer Test to be based on.

    Blockchain fundamentals
    Blockchain architecture
    Smart contract programming
    Blockchain protocols
    Cryptocurrency mining
    Decentralized storage
    Ethereum blockchain
    Hyperledger Fabric
    EOS blockchain
    Stellar blockchain
    Solidity programming language
    Web3.js library
    Truffle framework
    Ethereum Virtual Machine
    Token standards (ERC20, ERC721, etc.)
    ICO development
    Oracles and external data feeds
    Consensus algorithms (Proof of Work, Proof of Stake, etc.)
    Cross-chain interoperability
    Distributed ledger technology frameworks
    Permissioned vs permissionless blockchains
    Blockchain security best practices
    Double spending problem
    Private and public key cryptography
    Secure key storage
    Digital signatures
    Blockchain auditing
    Hash functions
    Peer-to-peer networks
    Blockchain data structures
    Token economics
    Web 3.0 and decentralized web
    Zero-knowledge proofs
    Sidechains and off-chain transactions
    Scalability solutions (sharding, layer 2 protocols, etc.)
    Enterprise blockchain solutions
    Blockchain as a service
    Smart contract testing
    Web application integration with blockchain
    Consensus protocol performance
    Blockchain use cases in supply chain management
    Identity management on blockchain
    Privacy in blockchain
    Blockchain for financial applications
    Smart contract vulnerabilities
    Gas and transaction fees
    Interplanetary File System (IPFS)
    Tokenization of assets
    Blockchain governance
    Decentralized autonomous organizations (DAOs)
    Cryptographic hash functions
    Blockchain regulation and compliance
    Blockchain scalability testing
    Blockchain development frameworks
    Blockchain analytics
    Decentralized finance (DeFi)
    Non-fungible tokens (NFTs)
    Blockchain consensus upgrades
    Cross-border payments on blockchain
    Blockchain marketplace development

What roles can I use the Blockchain Developer Test for?

  • Blockchain Developer
  • Smart Contract Developer
  • Blockchain Engineer
  • Cryptocurrency Developer
  • DApp Developer
  • Blockchain Consultant

How is the Blockchain Developer Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

  • Integrating blockchain technology into existing systems
  • Designing solutions for blockchain scalability challenges
  • Staying up-to-date with the latest developments in blockchain technology
  • Implementing encryption techniques and cryptographic protocols
  • Analyzing and optimizing blockchain performance
  • Troubleshooting and debugging blockchain applications
  • Auditing and assessing the security of blockchain networks
  • Implementing multi-signature and threshold signature schemes
  • Integrating off-chain solutions with on-chain transactions
  • Designing and implementing consensus protocols for private blockchains
  • Managing and monitoring blockchain network nodes and transactions
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The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

reduction in screening time

Blockchain Developer Hiring Test FAQs

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

  • Non-googleable questions
  • IP proctoring
  • Screen proctoring
  • Web proctoring
  • Webcam proctoring
  • Plagiarism detection
  • Secure browser
  • Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

You can check out our pricing plans.

Can I get a free trial?

Yes, you can sign up for free and preview this test.

I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

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40 min tests.
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