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Backend Engineer Online Test

About the test:

The Backend Engineer Online Test uses scenario-based MCQs to evaluate candidates on their knowledge of backend development, which involves designing and implementing server-side logic, databases, and APIs to support web and mobile applications. The test assesses candidates' proficiency in designing scalable and robust architectures, writing efficient code in languages such as Java, Python, or Ruby, building and integrating with databases, implementing RESTful APIs, and debugging and optimizing server-side code.

Covered skills:

  • Backend Development
  • API Design
  • Object-Oriented Programming
  • Performance Optimization
  • Database Design
  • Software Architecture
  • System Design

9 reasons why
9 reasons why

Adaface Backend Engineer Test is the most accurate way to shortlist Backend Engineers



Reason #1

Tests for on-the-job skills

The Backend Engineer Online 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:

  • Proficient in backend development using various programming languages
  • Strong understanding of database design and management
  • Able to design and develop APIs that adhere to industry best practices
  • Knowledgeable in software architecture principles and patterns
  • Skilled in object-oriented programming concepts and implementation
  • Experienced in system design and building scalable applications
  • Capable of performance optimization techniques and strategies
  • Proficient in troubleshooting and debugging complex backend issues
  • Ability to work with and integrate third-party APIs
  • Knowledge of security best practices for backend development
  • Familiarity with caching mechanisms and strategies
  • Understanding of data structures and algorithms in the backend context
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 Backend Engineer Test will be non-googleable.

🧐 Question

Medium

Broker Replication
System Design
Solve
You are working on a large-scale, distributed, and fault-tolerant message processing system designed to handle high throughput and low latency requirements. The system is based on the publish-subscribe pattern and uses multiple brokers to distribute messages across various topics and partitions. In this architecture, both publishers and subscribers are considered clients. The brokers are responsible for replicating messages among themselves to ensure fault tolerance and data durability.
 image
A client reports successfully publishing a message on a specific topic. However, one of the subscribers has not received the message. To investigate the issue, you have gathered detailed logs and system design data, as shown below:
 image
Based on the information provided, which of the following is the most likely reason for the issue?

A: The message was not published on the topic
B: Client C is not subscribed to the correct topic
C: There is a replication lag between brokers B1 and B2
D: Client C is consuming from the wrong broker
E: The message processing system failed to acknowledge the message

Medium

Load Balancer Latency
Debugging
Solve
A backend service is experiencing intermittent latency spikes while processing incoming requests. The service is deployed in a multi-node environment with a load balancer in front. You suspect that the issue might be related to resource contention. You collect the following performance metrics from the affected nodes during a spike:
 image
Which of the following is the most probable cause of the latency spikes?
A: High memory usage on the affected nodes.
B: Disk I/O bottlenecks on the affected nodes.
C: Insufficient CPU resources on the affected nodes.
D: Uneven distribution of incoming requests by the load balancer.
E: Network latency between the load balancer and the backend nodes.

Medium

Decryptor
Strings
Solve
What does the following pseudo code print?
 image

Hard

Fibonacci codes
Time Complexity
Pseudo Code
Solve
Here are three pseudocodes for calculating the Nth Fibonacci number. Which of the following statements about these codes are true?
 image
A: Time complexity/efficiency of CODE 1, CODE 2, CODE 3 is the same.
B: CODE 2 is more space-efficient than CODE 3.
C: CODE 3 is more space-efficient than CODE 2.
D: CODE 2 is more time-efficient than CODE 1.
E: CODE 3 is more time-efficient than CODE 1.

Hard

Palindrome Test cases
Strings
Solve
Go through the following faulty palindrome detection pseudocode and test cases. For which of the test cases would the code return true?
 image
Testcases
A: a
B: aba
C: aaa
D: aac

Medium

Rewards Activities Order
Database Connection
Solve
A new popular app tracks the activities performed by its users and grants them rewards based on each individual's total activities performed in a year. This data is maintained in a database table (activitesinfo), with the following columns: userid, totalactivities, reward. This year, due to fundraising activity, the company has decided to further reward its users by enhancing the reward as per the following formula: If reward < = 4000, increase it by 2%, If 4000 < reward <= 8000, increase it by 4%, If reward > 8000, increase it by 6%.
The tech team has written three different scripts to calculate increment for each slab, each script is to run as a separate transaction. Here are the three scripts:
Script 1:
For users with reward <= 4000, set reward = reward * 1.02

Script 2:
For users with reward > 4000 and reward <= 8000, set reward = reward * 1.04

Script 3:
For users with reward > 8000, set reward = reward * 1.06
Each script is to be executed separately. Which of the following options will update the rewards as expected:
A: Execute Script 1 followed by Script 2 followed by Script 3
B: Execute Script 2 followed by Script 3; Script 1 running concurrently throughout
C: Execute Script 3 followed by Script 2; Script 1 running concurrently throughout
D: Execute Script 3 followed by Script 2 followed by Script 1
E: Execute Script 2 followed by Script 3 followed by Script 1

Easy

Registration Queue
Logic
Queues
Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount.
For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition.
⚠️⚠️⚠️ Note:
- The first line of the input is the length of the array. The second line contains all the elements of the array.
- The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function.
- You need to "print" the final result (not return it) to pass the test cases.

For the example discussed above, the input will be:
5
20 70 -40 30 -10

Your code needs to print the following to the standard output:
20 70 30 -40 -10

Medium

Visitors Count
Strings
Logic
Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. 
Example:

Input:
WWMMWWCCC

Expected Output: 
4W3C2M

Explanation: 
‘W’ has the highest count, then ‘C’, then ‘M’. 
⚠️⚠️⚠️ Note:
- The input is already parsed and passed to a function.
- You need to "print" the final result (not return it) to pass the test cases.
- If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’.
- If any of them have the same count, the output should follow this order - M, W, C.
🧐 Question🔧 Skill

Medium

Broker Replication
System Design

3 mins

Backend
Solve

Medium

Load Balancer Latency
Debugging

3 mins

Backend
Solve

Medium

Decryptor
Strings

2 mins

Technical Aptitude
Solve

Hard

Fibonacci codes
Time Complexity
Pseudo Code

2 mins

Technical Aptitude
Solve

Hard

Palindrome Test cases
Strings

2 mins

Technical Aptitude
Solve

Medium

Rewards Activities Order
Database Connection

3 mins

Technical Aptitude
Solve

Easy

Registration Queue
Logic
Queues

30 mins

Coding
Solve

Medium

Visitors Count
Strings
Logic

30 mins

Coding
Solve
🧐 Question🔧 Skill💪 Difficulty⌛ Time
Broker Replication
System Design
Backend
Medium3 mins
Solve
Load Balancer Latency
Debugging
Backend
Medium3 mins
Solve
Decryptor
Strings
Technical Aptitude
Medium2 mins
Solve
Fibonacci codes
Time Complexity
Pseudo Code
Technical Aptitude
Hard2 mins
Solve
Palindrome Test cases
Strings
Technical Aptitude
Hard2 mins
Solve
Rewards Activities Order
Database Connection
Technical Aptitude
Medium3 mins
Solve
Registration Queue
Logic
Queues
Coding
Easy30 minsSolve
Visitors Count
Strings
Logic
Coding
Medium30 minsSolve
Reason #4

1200+ customers in 75 countries

customers in 75 countries
Brandon

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 Backend Engineer 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 Backend Engineer 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 Backend Engineer Assessment Test

Why you should use Pre-employment Backend Engineer Online Test?

The Backend Engineer 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:

  • Backend development using various programming languages and frameworks
  • Database design and management with popular database systems
  • API design and development for seamless communication between different software components
  • Software architecture design and implementation for scalable and maintainable systems
  • Object-oriented programming principles and best practices
  • System design to ensure efficient and reliable performance
  • Performance optimization techniques for enhancing application speed and responsiveness
  • Troubleshooting and debugging skills to identify and resolve issues
  • Version control using Git or other similar tools
  • Unit testing and knowledge of testing frameworks

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 Backend Engineer Online Test?

  • Backend Development

    Backend development refers to the creation and maintenance of the server-side logic that powers websites and applications. It involves tasks such as handling data storage, processing user requests, and managing server infrastructure. Measuring this skill ensures that candidates have a strong understanding of backend technologies and can effectively build robust and efficient backend systems.

  • Database Design

    Database design involves designing the structure and organization of databases to efficiently store and retrieve data. It includes tasks such as defining tables, creating relationships between them, and optimizing queries. Measuring this skill helps gauge a candidate's ability to create scalable and well-organized databases, which is essential for building reliable and performant applications.

  • API Design

    API design focuses on creating well-designed application programming interfaces (APIs) that enable communication between different software components. It involves determining appropriate endpoints, request/response formats, and authentication mechanisms. Measuring this skill ensures that candidates can create intuitive and developer-friendly APIs, promoting ease of integration and efficient collaboration.

  • Software Architecture

    Software architecture encompasses the high-level design and organization of software systems. It involves making decisions about the structure, components, and interactions of a system to meet functional and non-functional requirements. Measuring this skill helps evaluate a candidate's ability to create scalable, maintainable, and adaptable software architectures that facilitate flexible and robust application development.

  • Object-Oriented Programming

    Object-oriented programming (OOP) is a programming paradigm that organizes software design around objects that encapsulate data and behavior. It involves defining classes, creating objects, and using inheritance and polymorphism. Measuring this skill assesses a candidate's proficiency in utilizing OOP principles and techniques, enabling them to write modular, reusable, and extensible code.

  • System Design

    System design focuses on designing the architecture and components of large-scale systems. It involves identifying system requirements, specifying modules and interfaces, and considering scalability, fault tolerance, and performance. Measuring this skill ensures that candidates can design robust and efficient systems capable of handling high volumes of data and users.

  • Performance Optimization

    Performance optimization involves improving the speed, efficiency, and resource utilization of software systems. It includes tasks such as code profiling, identifying bottlenecks, and implementing optimizations. Measuring this skill helps identify candidates who understand the importance of optimizing software performance, enabling them to create highly responsive and scalable applications.

  • 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 Backend Engineer Test to be based on.

    Backend Development
    Frontend Development
    Database Design
    Relational Databases
    NoSQL Databases
    API Design
    RESTful APIs
    GraphQL
    Microservices
    Software Architecture
    MVC Architecture
    Layered Architecture
    Event-Driven Architecture
    Object-Oriented Programming
    Inheritance
    Polymorphism
    Encapsulation
    Abstraction
    System Design
    Scalability
    High Availability
    Load Balancing
    Data Partitioning
    Performance Optimization
    Caching
    Query Optimization
    Concurrency
    Troubleshooting
    Debugging
    Exception Handling
    Security Best Practices
    Authentication
    Authorization
    Encryption
    Third-Party API Integration
    OAuth
    Webhooks
    Logging
    Error Handling
    Caching Strategies
    Data Structures
    Arrays
    Linked Lists
    Stacks
    Queues
    Hash Tables
    Binary Trees
    Graphs
    Algorithms
    Sorting
    Searching
    Dynamic Programming
    Recursion
    Regular Expressions

What roles can I use the Backend Engineer Online Test for?

  • Backend Engineer
  • Full Stack Developer
  • Software Engineer
  • API Developer
  • Software Architect

How is the Backend Engineer Online 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

  • Experience with microservices architecture
  • Understanding of cloud computing and deployment
  • Knowledge of caching mechanisms and techniques
  • Design patterns and their application in software development
  • Experience with containerization technologies like Docker
  • Skills in designing and maintaining RESTful APIs
  • Knowledge of security best practices in software development
  • Experience with message queues and event-driven architectures
  • Understanding of distributed systems and their challenges
  • Proficiency in SQL and query optimization
  • Ability to optimize application performance and scalability with caching mechanisms

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on experience.

Singapore government logo

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.


85%
reduction in screening time

Backend Engineer 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.
No trick questions.
Accurate shortlisting.
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