Circle Software Engineer Interview Questions + Guide 2024

Circle is a leading financial technology company at the forefront of the internet of money, where value can travel globally with unparalleled speed and cost-efficiency, thanks to innovations like USDC, a blockchain-based dollar. Circle’s ambitious mission is to revolutionize payments, commerce, and global economic prosperity by leveraging groundbreaking blockchain infrastructure.

As a Software Engineer at Circle, you’ll be integral to extending and enhancing our in-house blockchain systems, ensuring reliable and secure API development, and collaborating with cross-functional teams to design cutting-edge, scalable solutions. This role requires strong technical expertise, excellent communication skills, and a commitment to continuous improvement and high standards. Join us in creating the future of digital finance.

Explore this guide to understand Circle’s interview process and prepare effectively for your Software Engineer interview!

Submitting Your Application

The first step is to submit a compelling application that reflects your technical skills and interest in joining Circle as a Software Engineer. Whether you were contacted by a Circle recruiter or have taken the initiative yourself, carefully review the job description and tailor your CV according to the prerequisites.

Tailoring your CV may include identifying specific keywords that the hiring manager might use to filter resumes and crafting a targeted cover letter. Furthermore, don’t forget to highlight relevant skills and mention your work experiences.

Recruiter/Hiring Manager Call Screening

If your CV happens to be among the shortlisted few, a recruiter from the Circle Talent Acquisition Team will make contact and verify key details like your experiences and skill level. Behavioral questions may also be a part of the screening process.

In some cases, the Circle Software Engineer hiring manager stays present during the screening round to answer your queries about the role and the company itself. They may also indulge in surface-level technical and behavioral discussions.

The whole recruiter call should take about 30 minutes.

CodeSignal Test

The next step in Circle’s interview process is to complete a CodeSignal test. This initial technical screening assesses your coding abilities through four coding questions. Successful completion of this test is crucial to move forward in the interview process.

Behavioral Questions (BQ) Interview

Following the CodeSignal test, you will have a Behavioral Questions (BQ) interview round with an engineer. This round focuses on understanding your motivations, past projects, and how you handle pressure. Key questions include:

• What interests you in Circle?
• Describe your most challenging projects.
• How do you behave under pressure?

This round does not contain any technical questions and primarily evaluates your fit within the company’s culture.

Take-Home Project

Based on interview performance, you will receive a take-home project. The take-home exercise typically involves practical tasks like frontend coding, web API development, or building a small system. This project often takes 5-7 hours to complete and will assess your ability to deliver high-quality code.

Onsite Interview Rounds

Upon successful completion of the take-home project, you will be invited for onsite interview rounds. This includes:

• System Design Round: Involves designing a system based on a given scenario (e.g., Design a ticketing system).
• Pair Programming: Work with an engineer to write a web API, which includes some SQL tasks.
• Behavioral Questions: Similar to the initial BQ round but may dive deeper into your teamwork, conflict resolution, and project management abilities.

These rounds collectively assess your technical proficiency and interpersonal skills for the role.

Quick Tips For Circle Software Engineer Interviews

• Brush Up On System Design And API Development: Expect questions on system design and API development. Practicing these areas can improve your confidence and performance.
• Be Honest and Reflective During Behavioral Interviews: Circle values integrity and mindfulness. Demonstrate these values through honest and reflective answers to behavioral questions.
• Prepare Thoroughly for Coding Tasks: Complete mock CodeSignal tests and take-home assignments to ensure you can efficiently solve problems under time constraints.

Typically, interviews at Circle Internet Financial vary by role and team, but commonly Software Engineer interviews follow a fairly standardized process across these question topics.

• Write a function search_list to check if a target value is in a linked list. Write a function, search_list, that returns a boolean indicating if the target value is in the linked_list or not. You receive the head of the linked list, which is a dictionary with keys value and next. If the linked list is empty, you’ll receive None.

• Write a query to find users who placed less than 3 orders or ordered less than $500 worth of product. Write a query to identify the names of users who placed less than 3 orders or ordered less than $500 worth of product. Use the transactions, users, and products tables.

• Create a function digit_accumulator to sum every digit in a string representing a floating-point number. You are given a string that represents some floating-point number. Write a function, digit_accumulator, that returns the sum of every digit in the string.

• Develop a function to parse the most frequent words used in poems. You’re hired by a literary newspaper to parse the most frequent words used in poems. Poems are given as a list of strings called sentences. Return a dictionary of the frequency that words are used in the poem, processed as lowercase.

• Write a function rectangle_overlap to determine if two rectangles overlap. You are given two rectangles a and b each defined by four ordered pairs denoting their corners on the x, y plane. Write a function rectangle_overlap to determine whether or not they overlap. Return True if so, and False otherwise.

• How would you design a function to detect anomalies in univariate and bivariate datasets? If given a univariate dataset, how would you design a function to detect anomalies? What if the data is bivariate?

• What are the drawbacks of the given student test score data layouts, and how would you reformat them? Assume you have data on student test scores in two layouts. Identify the drawbacks of these layouts, suggest formatting changes for better analysis, and describe common problems in “messy” datasets.

• What is the expected churn rate in March for customers who bought a subscription since January 1st? You noticed that 10% of customers who bought subscriptions in January 2020 canceled before February 1st. Assuming uniform new customer acquisition and a 20% month-over-month decrease in churn, calculate the expected churn rate in March for all customers who bought the product since January 1st.

• How would you explain a p-value to a non-technical person? Describe what a p-value is in simple terms for someone who is not familiar with technical or statistical concepts.

• What are Z and t-tests, and when should you use each? Explain what Z and t-tests are, their uses, the differences between them, and when to use one over the other.

• How does random forest generate the forest and why use it over logistic regression? Explain the process of how random forest generates multiple decision trees to form a forest. Discuss the advantages of using random forest over logistic regression, such as handling non-linear data and reducing overfitting.

• When would you use a bagging algorithm versus a boosting algorithm? Compare two machine learning algorithms and describe scenarios where bagging is preferred over boosting. Provide examples of the tradeoffs, such as variance reduction in bagging and bias reduction in boosting.

• How would you evaluate and compare two credit risk models for personal loans?

1. Identify the type of model developed by the co-worker for loan approval.
2. Describe how to measure the difference between two credit risk models over a timeframe, considering monthly installments.
3. List the metrics to track for measuring the success of the new model, such as accuracy, precision, recall, and AUC-ROC.

• What’s the difference between Lasso and Ridge Regression? Explain the key differences between Lasso and Ridge Regression, focusing on their regularization techniques and how they handle feature selection and multicollinearity.

• What are the key differences between classification models and regression models? Describe the fundamental differences between classification and regression models, including their objectives, output types, and common use cases.

• What are the Z and t-tests, and when should you use each? Explain the purpose and differences between Z and t-tests. Describe scenarios where one test is preferred over the other.

• How would you reformat student test score data for better analysis? Given two datasets of student test scores, identify drawbacks in their current format. Suggest formatting changes and discuss common issues in “messy” datasets.

• What metrics would you use to evaluate the value of marketing channels? Given data on marketing channels and costs for a B2B analytics company, identify key metrics to determine the value of each channel.

• How would you determine the next partner card using customer spending data? With access to customer spending data, outline a method to identify the best partner for a new credit card offering.

• How would you investigate if an email campaign led to increased conversion rates? An E-commerce store’s new email journey increased conversion rates from 40% to 43%. Investigate if the redesign caused the increase or if other factors were involved.

What is the average salary for a Software Engineer at Circle?

Q: What is the interview process for a Software Engineer position at Circle?

The interview process typically starts with a CodeSignal test, followed by behavioral questions (BQ) with an engineer. Subsequent rounds include system design questions, API development tests, and often a take-home project.

Q: What kind of technical challenges can I expect during the interview?

You can expect a range of challenges including system design questions, API development, coding tests, and potentially a take-home project focusing on front-end or back-end technologies.

Q: What qualities does Circle value in an employee?

Circle values dedication to customers and stakeholders, mindfulness, excellence, and high integrity. They look for team players committed to transparency and innovation.

Q: What does the role of Software Engineer at Circle involve?

The role involves building and extending Circle’s blockchain systems, developing scalable microservices, creating secure APIs, collaborating with product teams, and ensuring high-quality code and system design.

Q: What benefits does Circle offer?

Circle offers competitive compensation, annual bonuses, equity options, health benefits (medical, dental, vision), 401(k) plan, discretionary vacation policy, paid sick leave, and paid holidays. The company is also an equal opportunity employer and values diversity.

Conclusion

Excited about joining Circle? You’re about to dive into one of the most innovative financial technology companies at the forefront of the emerging internet of money. With a dynamic and inclusive work culture combined with cutting-edge technology, Circle provides a unique environment where your contributions will shape the future of digital finance.

If you want more insights into the company, check out our comprehensive Circle Interview Guide. At Interview Query, we are dedicated to helping you master your interview skills with a complete toolkit, providing you with the knowledge, confidence, and strategic guidance to ace every software engineer interview question and challenge.

Explore all our company interview guides to boost your preparation. If you have any questions, feel free to reach out to us.

Good luck with your interview!