As a Software Engineer at Liberty Mutual, you play a pivotal role in shaping the future of insurance technology. This position is essential in developing innovative software solutions that enhance user experiences, streamline operations, and drive business success. You will be working in a dynamic environment that emphasizes collaboration and creativity, contributing to projects that have significant impacts on products and services utilized by millions of customers. The work of a Software Engineer at Liberty Mutual encompasses a variety of challenges, from developing robust applications to deploying scalable systems. You will work alongside cross-functional teams, including product managers, designers, and other engineers, to solve complex problems that improve the efficiency and reliability of the company's offerings. Your contributions will directly influence how customers interact with insurance products, making this role both impactful and rewarding. In this position, you will engage with state-of-the-art technology stacks and methodologies, allowing you to grow your skills while being part of a larger mission to modernize the insurance industry. Expect to be involved in a culture that values diversity of thought and encourages continuous learning, making it an exciting opportunity for anyone passionate about technology and innovation.
Phone Screen
reportedInitial phone screen conducted by a recruiter to assess candidate fit.
What to demonstrate
- Initial phone screen conducted by a recruiter to assess candidate fit
- Depth in Data Structures
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 Interviews
reportedOne or more interviews focusing on coding and problem-solving skills.
What to demonstrate
- One or more interviews focusing on coding and problem-solving skills
- Depth in Data Structures
How to prepare
- Answer aloud and timed: Can you explain the differences between REST and SOAP APIs?
- Answer aloud and timed: What is your experience with cloud technologies like AWS or Azure?
Behavioral Questions
reportedCombination of behavioral and technical questions reflecting collaboration and user-centric development.
What to demonstrate
- Combination of behavioral and technical questions reflecting collaboration and user-centric development
- Depth in Data Structures
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral questions above and write down what you would ask to confirm before it.
Coding Challenges
reportedAssess ability to write efficient and maintainable code through coding challenges.
What to demonstrate
- Assess ability to write efficient and maintainable code through coding challenges
- Depth in Data Structures
How to prepare
- Answer aloud and timed: How would you implement a binary search algorithm?
- Answer aloud and timed: Given an array of integers, find two numbers that add up to a specific target.
PracHub editorial advice for the preparation topics above.
Prepare Thoroughly
Familiarize yourself with common data structures and algorithms, as these are frequently tested in coding interviews.
Practice Behavioral Questions
Use the STAR method to articulate your past experiences effectively, emphasizing your contributions and outcomes.
Clarify Questions
If you don’t understand a question during the interview, don’t hesitate to ask for clarification. It shows your willingness to engage and ensures you’re on the right track.
Show Enthusiasm
Demonstrating genuine interest in the role and the company can leave a positive impression on your interviewers.
Follow Up
After your interviews, consider sending a thank-you note to express appreciation for the opportunity and reiterate your interest in the position.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
How do you manage memory in your applications?
How do you manage memory in your applications?
Approach
- Say what the runtime actually does before reasoning about the code.
- Name what is shared across threads and what owns each piece of state.
- Identify the window where an invariant is briefly untrue.
- Distinguish a value from a reference to it, and say which one you handed out.
Follow-up
- What happens if two callers reach this at the same time?
- Where could this allocate more than you expect?
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 an array of integers, find two numbers that add up to a specific target.
Given an array of integers, find 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 time complexity of your solution.
Explain the time complexity of your solution.
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?
Solve a problem using recursion and explain your approach.
Solve a problem using recursion and explain your approach.
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?
Denormalise tenant onto revisions and backfill it live
resource_revision (revision_id, resource_id, version, actor_user_id, change_kind, patch, request_id, created_at) has 400M rows and no tenant column; tenant_id lives only on resource. Two reads need it: a tenant-scoped audit feed ordered by created_at DESC, and an offboarding purge. Both join back to resource today. Justify adding tenant_id to resource_revision against those two reads, name the anomaly the copy introduces and the constraint that prevents it, then give the ordered migration for a live table taking 1.2k writes/second — the lock each step takes, how the backfill is batched, and where each step stops being reversible. PostgreSQL 16.
Approach
- Justify from the access path rather than from taste. Without the column, the audit feed either scans resource_revision by created_at and discards other tenants' rows, or resolves the tenant's resource_ids first and probes with them — both proportional to the tenant's whole history rather than to one page. With (tenant_id, created_at DESC, revision_id DESC) it is a seek that stops at 50 rows, and the purge becomes a ranged delete instead of a join.
- Name the cost exactly: a second copy of a fact can disagree with the first. Make the disagreement unwritable rather than documented — add UNIQUE (resource_id, tenant_id) on resource so it can serve as a foreign-key target, then FOREIGN KEY (resource_id, tenant_id) REFERENCES resource (resource_id, tenant_id) on the revision table. A revision can then only ever carry its parent's tenant.
- Step one, expand: ALTER TABLE resource_revision ADD COLUMN tenant_id BIGINT NULL, with no default, so it is a catalogue change and no rewrite. It still needs ACCESS EXCLUSIVE for an instant, and that instant queues behind the longest open transaction on the table while every later query queues behind it — set lock_timeout to 2s and retry rather than wait.
- Step two, dual-write: deploy the writer that populates tenant_id on every new revision while reads still use the join. Reversible by redeploying the previous build, because nothing reads the column yet.
Follow-up
- The backfill is half finished and a rollback is required. What state is the table in, and what does the previous build do with a half-populated column?
- How do you verify the backfill actually finished, given rows are still being inserted while it runs?
Stop tag and share joins from fanning out a page
resource_tag is (resource_id, tag_id) with PK (resource_id, tag_id); resource_share is (resource_id, shared_with_user_id, permission). The tagged-and-shared listing inner-joins resource to both, filters tenant_id, tag_id = ANY($2) and shared_with_user_id = $3, orders by updated_at DESC and takes 50. Pages come back with fewer than 50 distinct resources and the total in the header is far too high. Explain the row multiplication, rewrite both the page query and the count query so each is correct, and name the index each one needs. PostgreSQL 16.
Approach
- Do the arithmetic against the predicates that are actually there. An inner join emits one row per matching child row, and both joins are filtered: tag_id = ANY($2) admits only the requested tags, shared_with_user_id = $3 admits one user's share rows. So a resource holding three of the requested tags and shared with $3 once yields three rows, not one — the multiplier is its count of matching tags times its share rows for that single user, and that second factor is 1 unless the table admits duplicate (resource_id, shared_with_user_id) pairs. LIMIT 50 then limits rows rather than resources, and COUNT(*) counts pairs — the header is the product, not the population.
- Reject DISTINCT as the fix. It deduplicates after the product has been built, so the planner must materialise and sort the fanned-out set before the LIMIT can apply, and it leaves any SUM or AVG in the same select list wrong.
- Rewrite both filters as semi-joins, keeping resource as the only row source: AND EXISTS (SELECT 1 FROM resource_tag rt WHERE rt.resource_id = r.resource_id AND rt.tag_id = ANY($2)) and the same shape against resource_share. A semi-join stops at the first match per resource and preserves the driving index order, so ORDER BY updated_at DESC, resource_id DESC LIMIT 50 still stops after 50 rows.
- Count with the same predicates and no join at all: SELECT count(*) FROM resource r WHERE r.tenant_id = $1 AND r.status = 'active' AND EXISTS (...) AND EXISTS (...). Nothing multiplies a resource, so the number is the population.
Follow-up
- The filter changes from 'any of these tags' to 'all of these tags'. Rewrite it and state what it costs relative to the ANY form.
- A resource can be shared with the same user twice under different permissions. Does your count change, and should it?
What are the key principles of object-oriented programming?
What are the key principles of object-oriented programming?
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?
Can you explain the differences between REST and SOAP APIs?
Can you explain the differences between REST and SOAP APIs?
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?
Present a case where you had to balance technical debt with feature delivery.
Present a case where you had to balance technical debt with feature delivery.
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 scaling an application to handle increased user load?
How would you approach scaling an application to handle increased user load?
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 scenario where you had to make a trade-off between quality and speed.
Describe a scenario where you had to make a trade-off between quality and speed.
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 issue?
How would you approach debugging a complex application issue?
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 Liberty Mutual candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Liberty Mutual loop
- Write out the reported sequence: Phone Screen, Technical Interviews, Behavioral Questions, Coding Challenges.
- 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 4 reported rounds, with the weakest marked.
02Work Data Structures
- Spend the session on Data Structures, which Liberty Mutual candidates report being tested on.
- Write one worked example in Data Structures and time yourself on it.
Deliverable: One timed worked example in Data Structures.
03Work Algorithms
- Spend the session on Algorithms, which Liberty Mutual candidates report being tested on.
- Write one worked example in Algorithms and time yourself on it.
Deliverable: One timed worked example in Algorithms.
04Work Coding Challenges (General)
- Spend the session on Coding Challenges (General), which Liberty Mutual candidates report being tested on.
- Write one worked example in Coding Challenges (General) and time yourself on it.
Deliverable: One timed worked example in Coding Challenges (General).
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What are the key principles of object-oriented programming?
- Answer aloud, timed: How do you manage memory in your applications?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Coding / Algorithms
- Answer aloud, timed: Write a function to reverse a linked list.
- Answer aloud, timed: How would you implement a binary search algorithm?
Deliverable: Spoken answers to 2 reported Coding / Algorithms question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Tell me about a challenging project you worked on. What was your role?
- Answer aloud, timed: Describe a time when you had to deal with conflict in a team setting.
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.
What is your experience with cloud technologies like AWS or Azure?
What is your experience with cloud technologies like AWS or Azure?
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 time when you optimized a piece of code for performance.
Describe a time when you optimized a piece of code for performance.
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?
Tell me about a challenging project you worked on. What was your role?
Tell me about a challenging project you worked on. What was your role?
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 time when you had to deal with conflict in a team setting.
Describe a time when you had to deal with conflict in a team setting.
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 your work when facing multiple deadlines?
How do you prioritize your work when facing multiple deadlines?
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?
What is your approach to receiving and providing feedback?
What is your approach to receiving and providing feedback?
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?
Discuss a time when you had to learn a new technology quickly.
Discuss a time when you had to learn a new technology quickly.
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 time when you had to redesign a system. What factors did you consider?
Describe a time when you had to redesign a system. What factors did you consider?
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
What is your experience with cloud technologies like AWS or Azure?
- 02
Describe a time when you optimized a piece of code for performance.
- 03
Tell me about a challenging project you worked on. What was your role?
- 04
Describe a time when you had to deal with conflict in a team setting.
How difficult are the interviews, and how much preparation time is typically required?
The interviews can be moderately challenging, focusing on both technical and behavioral aspects. Candidates often find that 2-4 weeks of focused preparation is beneficial.
Liberty Mutual Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates typically demonstrate a strong blend of technical skills and effective communication. They can articulate their thought process clearly and show a willingness to learn and adapt.
Liberty Mutual Software Engineer candidate reports ↗What is the culture like at Liberty Mutual?
The culture emphasizes collaboration, diversity, and continuous improvement. Employees are encouraged to express their ideas and contribute to a supportive work environment.
Liberty Mutual Software Engineer candidate reports ↗How long does the interview process take?
The timeline can vary but expect the process to take anywhere from a few weeks to over a month, depending on the interviewing team’s schedule and responsiveness.
Liberty Mutual Software Engineer candidate reports ↗Are there opportunities for remote work?
Yes, Liberty Mutual offers flexible work arrangements, including remote positions, depending on the role and team requirements.
Liberty Mutual Software Engineer candidate reports ↗What topics does Liberty Mutual test in interviews?
Liberty Mutual interviews most often cover Behavioral Interviewing, Stakeholder Management, Problem Solving, Cross-Functional Collaboration, and Case Study Analysis. The exact emphasis depends on the specific role you apply for.
Liberty Mutual 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.
- 01Liberty Mutual 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
Explore related engineering environments and compare the preparation focus.
Vercel Software Engineer Interview Guide
Debugging practice for Vercel software engineer prep built on a reproduction you trust, narrowing to the smallest failing input, and changing one variable per run so the result stays attributable.
Together Ai Software Engineer Interview Guide
Failure-handling practice for Together Ai software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
Lambda Software Engineer Interview Guide
Failure-handling practice for Lambda software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
CoreWeave Software Engineer Interview Guide
Failure-handling practice for CoreWeave software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.