As a Software Engineer at Hearts & Science, you play a pivotal role in developing innovative technology solutions that drive marketing effectiveness and enhance customer engagement. This position is integral to the company's mission of leveraging data and technology to create personalized advertising experiences. You will work on projects that span various sectors, contributing to the design and implementation of software that supports complex analytics and decision-making processes. The impact of your work extends beyond just coding. You will collaborate closely with cross-functional teams, including data scientists and marketing strategists, to develop tools that not only meet business objectives but also improve user experiences. This role is critical as it combines technical expertise with strategic thinking, allowing you to influence product direction and drive significant business outcomes. Expect to engage in challenging projects that push the boundaries of technology while delivering tangible results for clients.
Phone Screen
reportedInitial screening to assess candidate's background and fit for the role.
What to demonstrate
- Initial screening to assess candidate's background and fit for the role
- Depth in Software Engineering (General)
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Technical Assessment
reportedEvaluation of technical competencies through coding challenges and problem-solving questions.
What to demonstrate
- Evaluation of technical competencies through coding challenges and problem-solving questions
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: Describe a challenging bug you encountered in a project and how you resolved it.
- Answer aloud and timed: How do you ensure the quality of your code before deploying it?
In-Person Interviews
reportedMultiple rounds of interviews focusing on technical skills, behavioral competencies, and cultural fit.
What to demonstrate
- Multiple rounds of interviews focusing on technical skills, behavioral competencies, and cultural fit
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: Discuss a project where you implemented a new technology or framework. What was your approach?
- Answer aloud and timed: How would you design a system to handle real-time data processing?
PracHub editorial advice for the preparation topics above.
Practice Coding
Regularly practice coding problems on platforms like LeetCode or HackerRank to sharpen your skills and improve your confidence.
Prepare for Behavioral Questions
Reflect on your past experiences and be ready to discuss them in detail, focusing on your role, actions, and the outcomes.
Understand the Company’s Products
Familiarize yourself with Hearts & Science's products and services, as understanding the business context can help you during interviews.
Ask Insightful Questions
Prepare thoughtful questions to ask your interviewers. This demonstrates your interest in the role and helps you assess if the company is the right fit for you.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a function to reverse a linked list.
Write a function to reverse a linked list.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
How would you implement a binary search algorithm?
How would you implement a binary search algorithm?
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Given a list of integers, find the two numbers that add up to a specific target.
Given a list of integers, find the two numbers that add up to a specific target.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Explain the difference between depth-first search and breadth-first search.
Explain the difference between depth-first search and breadth-first search.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Can you explain how you would optimize a SQL query for performance?
Can you explain how you would optimize a SQL query for performance?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
What are the trade-offs between SQL and NoSQL databases in a project context?
What are the trade-offs between SQL and NoSQL databases in a project context?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
What programming languages are you most proficient in, and how have you applied them in your projects?
What programming languages are you most proficient in, and how have you applied them in your projects?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe a challenging bug you encountered in a project and how you resolved it.
Describe a challenging bug you encountered in a project and how you resolved it.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How do you ensure the quality of your code before deploying it?
How do you ensure the quality of your code before deploying it?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Discuss a project where you implemented a new technology or framework. What was your approach?
Discuss a project where you implemented a new technology or framework. What was your approach?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you design a system to handle real-time data processing?
How would you design a system to handle real-time data processing?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
What considerations would you take into account when designing a microservices architecture?
What considerations would you take into account when designing a microservices architecture?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Describe how you would approach building a RESTful API for a web application.
Describe how you would approach building a RESTful API for a web application.
Approach
- Say who the caller is and what they do when the call fails halfway.
- Define the identity of a request so a retry cannot double-apply it.
- Separate accepted, pending, failed and confirmed; they are different facts.
- Design the error taxonomy before the success shape; callers branch on it.
Follow-up
- What happens if the caller retries after a timeout?
- How does a client discover it is on an old version of this contract?
How do you ensure that your system is resilient and fault-tolerant?
How do you ensure that your system is resilient and fault-tolerant?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Given a dataset, how would you identify trends and insights?
Given a dataset, how would you identify trends and insights?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
If you were given a project with tight deadlines, how would you manage expectations with stakeholders?
If you were given a project with tight deadlines, how would you manage expectations with stakeholders?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How do you approach learning a new technology or tool quickly?
How do you approach learning a new technology or tool quickly?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you approach debugging a complex application?
How would you approach debugging a complex application?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- Separate the trigger from the cause; the deploy is rarely the bug.
Follow-up
- What would you look at first, and what would it rule out?
- How would you tell a cause from a coincidence here?
Built from the rounds and topics Hearts & Science candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Hearts & Science loop
- Write out the reported sequence: Phone Screen, Technical Assessment, In-Person Interviews.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.
02Work Software Engineering (General)
- Spend the session on Software Engineering (General), which Hearts & Science candidates report being tested on.
- Write one worked example in Software Engineering (General) and time yourself on it.
Deliverable: One timed worked example in Software Engineering (General).
03Work Writing Production Code
- Spend the session on Writing Production Code, which Hearts & Science candidates report being tested on.
- Write one worked example in Writing Production Code and time yourself on it.
Deliverable: One timed worked example in Writing Production Code.
04Work Problem Solving
- Spend the session on Problem Solving, which Hearts & Science candidates report being tested on.
- Write one worked example in Problem Solving and time yourself on it.
Deliverable: One timed worked example in Problem Solving.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What programming languages are you most proficient in, and how have you applied them in your projects?
- Answer aloud, timed: Can you explain how you would optimize a SQL query for performance?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: System Design / Architecture
- Answer aloud, timed: How would you design a system to handle real-time data processing?
- Answer aloud, timed: What considerations would you take into account when designing a microservices architecture?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time when you had to collaborate with a difficult team member. How did you handle it?
- Answer aloud, timed: How do you prioritize tasks when working on multiple projects simultaneously?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
Describe a time when you had to collaborate with a difficult team member. How did you handle it?
Describe a time when you had to collaborate with a difficult team member. How did you handle it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you prioritize tasks when working on multiple projects simultaneously?
How do you prioritize tasks when working on multiple projects simultaneously?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Share an example of a project where you took the lead. What was the outcome?
Share an example of a project where you took the lead. What was the outcome?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you handle feedback and criticism regarding your work?
How do you handle feedback and criticism regarding your work?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe a situation where you had to adapt to a significant change in a project.
Describe a situation where you had to adapt to a significant change in a project.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe your methodology for conducting a code review. What do you look for?
Describe your methodology for conducting a code review. What do you look for?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you handle edge cases in your coding solutions?
How do you handle edge cases in your coding solutions?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
- 01
Describe a time when you had to collaborate with a difficult team member. How did you handle it?
- 02
How do you prioritize tasks when working on multiple projects simultaneously?
- 03
Share an example of a project where you took the lead. What was the outcome?
- 04
How do you handle feedback and criticism regarding your work?
How difficult is the interview process, and how much preparation time is typical?
The interview process is rigorous and designed to assess both technical and behavioral competencies. Candidates typically prepare for several weeks, focusing on coding challenges, system design, and behavioral questions.
Hearts & Science Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate a strong technical foundation, effective problem-solving skills, and the ability to communicate clearly. They also align closely with the company’s values and culture.
Hearts & Science Software Engineer candidate reports ↗What is the culture and working style at Hearts & Science?
Hearts & Science fosters a collaborative and innovative environment, encouraging team members to share ideas and take initiative. A strong emphasis is placed on data-driven decision-making and user-centric design.
Hearts & Science Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The timeline can vary, but candidates generally move from initial screenings to in-person interviews within a few weeks, followed by final offers shortly thereafter.
Hearts & Science Software Engineer candidate reports ↗Are there remote work or hybrid expectations?
While this may vary by role and team, many positions at Hearts & Science offer flexible working arrangements, including remote or hybrid options, depending on project needs.
Hearts & Science Software Engineer candidate reports ↗What topics does Hearts & Science test in interviews?
Hearts & Science interviews most often cover Data analysis, SQL, Software Engineering (General), Python, and Writing Production Code. The exact emphasis depends on the specific role you apply for.
Hearts & Science Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.
- 01Hearts & Science Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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