Dandy Software Engineer Interview Questions + Guide in 2025

Dandy is a forward-thinking company focused on leveraging technology to enhance customer experiences in the dental industry.

As a Software Engineer at Dandy, you will play a crucial role in developing and maintaining software solutions that streamline processes and improve operational efficiency. Key responsibilities include designing and implementing data models, collaborating with cross-functional teams to understand user needs, and building scalable software applications. Proficiency in programming languages such as Python and SQL is essential, along with a solid understanding of algorithms, data structures, and system design principles. Ideal candidates will exhibit strong problem-solving skills, the ability to work under pressure, and a commitment to delivering high-quality code. Given Dandy's emphasis on innovation and efficiency, a great fit for this role will also embrace an iterative approach to development and demonstrate resilience in navigating a fast-paced environment.

This guide will help you prepare effectively for your interview by providing insights into the role's expectations and the types of questions you might encounter, allowing you to present your skills and experiences in the best light possible.

The interview process for a Software Engineer at Dandy is structured to assess both technical skills and cultural fit within the team. It typically consists of several stages, each designed to evaluate different aspects of a candidate's capabilities.

1. Initial Screening

The process begins with an initial screening, usually conducted by a recruiter. This call lasts about 30 minutes and focuses on discussing the role, the company culture, and your background. The recruiter will gauge your interest in the position and assess whether your skills align with the requirements of the role.

2. Technical Assessment

Following the initial screening, candidates are required to complete a technical assessment. This may involve an online coding test, often hosted on platforms like HackerRank, where you will face a series of timed questions that test your proficiency in SQL and programming languages such as Python. The time constraints can be tight, so it's essential to be prepared for quick problem-solving.

3. Technical Screen

After successfully completing the technical assessment, candidates move on to a technical screen, which is typically conducted via video call. This session usually lasts about an hour and includes live coding exercises and problem-solving questions. Interviewers may ask you to demonstrate your coding skills in real-time, so be ready to articulate your thought process as you work through the problems.

4. Onsite Interviews

The final stage consists of multiple onsite interviews, which may be conducted remotely. This phase usually includes four rounds, each lasting around 45 minutes. The interviews cover a range of topics, including system design, coding challenges, and behavioral questions. You may also be asked to discuss past projects in detail, showcasing your experience and how it relates to the role at Dandy.

Throughout the interview process, candidates should be prepared for a mix of technical and behavioral questions, as well as scenarios that assess their problem-solving abilities and cultural fit within the company.

Now that you have an understanding of the interview process, let's delve into the specific questions that candidates have encountered during their interviews at Dandy.

Here are some tips to help you excel in your interview.

Understand the Interview Structure

Dandy's interview process typically includes multiple stages: an initial phone screen, a technical assessment, and several rounds of onsite interviews. Familiarize yourself with this structure and prepare accordingly. Expect to engage in coding challenges, system design discussions, and behavioral interviews. Knowing what to expect can help you manage your time and energy throughout the process.

Prepare for Technical Assessments

Technical assessments at Dandy often involve SQL and Python questions, as well as coding challenges that may require you to implement algorithms or data structures. Brush up on your coding skills, particularly on platforms like LeetCode, and practice solving problems under time constraints. Be ready to explain your thought process clearly, as communication is key during these assessments.

Be Ready for Behavioral Questions

Dandy places importance on cultural fit and collaboration. Prepare for behavioral questions that assess your teamwork, problem-solving abilities, and how you handle challenges. Reflect on past experiences where you demonstrated these qualities, and be ready to discuss them in detail. This will help you convey your alignment with the company’s values.

Stay Calm Under Pressure

Interviews at Dandy can be intense, with some candidates reporting a high-pressure environment. Practice staying calm and composed, especially during coding challenges. If you encounter a difficult problem, take a moment to gather your thoughts before diving in. Communicate your approach and reasoning clearly, even if you’re unsure of the final solution.

Ask Insightful Questions

During your interviews, take the opportunity to ask questions about the team dynamics, company culture, and expectations. This not only shows your interest in the role but also helps you gauge if Dandy is the right fit for you. Be cautious of red flags, such as high turnover rates or a lack of support for employees, as these can impact your long-term satisfaction.

Practice Time Management

Many candidates have noted that the time constraints during assessments can be challenging. Practice managing your time effectively during coding exercises. If you find yourself stuck, it’s better to move on to another question and return later if time allows. This strategy can help you maximize your performance across the entire assessment.

Reflect on Feedback

If you receive feedback during the interview process, take it constructively. Some candidates have reported feeling dismissed or undervalued during interviews. Use any feedback as a learning opportunity to improve your skills and approach for future interviews, whether at Dandy or elsewhere.

By following these tips and preparing thoroughly, you can enhance your chances of success in the interview process at Dandy. Good luck!

In this section, we’ll review the various interview questions that might be asked during a Software Engineer interview at Dandy. The interview process will likely assess your technical skills, problem-solving abilities, and cultural fit within the team. Be prepared to demonstrate your knowledge in coding, data modeling, and system design, as well as your ability to communicate effectively.

Coding and Algorithms

1. Can you implement a function to flatten a nested list?

This question tests your understanding of data structures and recursion.

How to Answer

Explain your thought process clearly, and consider edge cases. Discuss the time and space complexity of your solution.

Example

“I would use a recursive approach to iterate through the list. If the element is a list, I would call the function recursively; otherwise, I would append it to the result list. This ensures that all elements are flattened regardless of their nesting level.”

2. Given a JSON object of preferences, how would you subtract common preferences from a list of other objects?

This question evaluates your ability to manipulate data structures and perform operations on them.

How to Answer

Outline your approach to parsing the JSON and iterating through the list. Discuss how you would handle duplicates and ensure efficiency.

Example

“I would first convert the JSON object into a dictionary for easy access. Then, I would iterate through the list of objects, checking each one against the preferences dictionary and removing any common elements. This would be done in linear time to maintain efficiency.”

3. How would you design a system for handling dental implant orders at the data layer?

This question assesses your system design skills and understanding of database management.

How to Answer

Discuss the entities involved, relationships, and how you would structure the database. Mention normalization and indexing for performance.

Example

“I would create tables for orders, customers, and products, ensuring that foreign keys maintain relationships. I would also implement indexing on frequently queried fields to optimize performance and ensure data integrity through constraints.”

4. Write a function to find all available 30-minute appointment slots given a set of time blocks.

This question tests your algorithmic thinking and ability to work with time data.

How to Answer

Explain how you would iterate through the time blocks and check for gaps. Discuss edge cases like overlapping time blocks.

Example

“I would first sort the time blocks by start time. Then, I would iterate through the sorted list, checking for gaps between the end of one block and the start of the next. If a gap of 30 minutes or more is found, I would record it as an available slot.”

5. Given an unsorted array of size n, where one number is missing and one occurs twice, how would you find these numbers?

This question evaluates your problem-solving skills and understanding of arrays.

How to Answer

Discuss your approach to using mathematical properties or hash maps to identify the missing and duplicate numbers.

Example

“I would calculate the expected sum of the first n natural numbers and compare it to the actual sum of the array. The difference gives the missing number, while I would use a hash map to track occurrences to find the duplicate.”

SQL and Data Modeling

1. How would you model and query a database that manages orders?

This question assesses your understanding of database design and SQL querying.

How to Answer

Discuss the tables you would create, their relationships, and how you would write queries to retrieve data.

Example

“I would create an orders table with fields for order ID, customer ID, product ID, and timestamps. To query for all orders by a specific customer, I would use a JOIN statement to link the orders table with the customers table based on customer ID.”

2. Write a SQL query to get customers who have orders in specific groups without allowing duplicate records.

This question tests your SQL skills and ability to handle data integrity.

How to Answer

Explain how you would use DISTINCT and JOINs to achieve the desired result.

Example

“I would write a query that selects DISTINCT customer IDs from the orders table, joining it with the groups table to filter by the specified groups. This ensures that each customer is listed only once.”

3. Given a set of time blocks, how would you find overlapping appointments?

This question evaluates your ability to work with time data and identify conflicts.

How to Answer

Discuss your approach to sorting the time blocks and checking for overlaps.

Example

“I would sort the time blocks by start time and then iterate through the list, checking if the start time of the current block is less than the end time of the previous block. If it is, there’s an overlap.”

4. How would you transform data from one format to another in SQL?

This question assesses your data transformation skills.

How to Answer

Explain the SQL functions you would use to manipulate and transform the data.

Example

“I would use the CASE statement to transform data based on conditions, and functions like CONCAT or CAST to change data types as needed. This allows for flexible data manipulation during queries.”

5. Can you explain how to debug a counterintuitive numerical result in a SQL query?

This question tests your analytical skills and attention to detail.

How to Answer

Discuss your approach to identifying the source of the error and validating the results.

Example

“I would start by reviewing the query logic and checking for any joins that might be causing unexpected results. I would also validate the data in the tables to ensure there are no anomalies affecting the output.”