Interview guides · Fm global

Fm global Software Engineer Interview Guide

Fm global Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

As a Software Engineer at FM Global, you occupy a critical position within one of the world’s most respected commercial property insurers. Your work directly supports the company’s mission of engineering-driven risk management. You are not just writing code; you are building the digital infrastructure that allows FM Global to analyze complex physical risks and protect multibillion-dollar assets globally. The role requires a blend of technical precision and an appreciation for high-stakes problem solving. You will work on platforms that handle significant data volumes, often collaborating with cross-functional teams to modernize legacy systems or build new, scalable solutions.

This guide is scoped to a Software Engineer candidate at Fm global.

Focus areas

Object-Oriented Programming (OOP)
Inheritance
SQL (Structured Query Language)

The Fm global interview process

Fm global candidates report 5 rounds over 4-6 weeks. The stages below are what candidates describe, not a published process.

Initial Contact

Candidates are contacted to begin the interview process.

What to demonstrate

Candidates are contacted to begin the interview process
Depth in Object-Oriented Programming (OOP)

How to prepare

Answer aloud and timed: Describe a time you had to manage a difficult project deadline.
Answer aloud and timed: What are your greatest professional strengths and weaknesses?

Screening Rounds

Candidates navigate a series of screens to assess technical fit.

What to demonstrate

Candidates navigate a series of screens to assess technical fit
Depth in Object-Oriented Programming (OOP)

How to prepare

Answer aloud and timed: How do you handle disagreements within a technical team?
Answer aloud and timed: Why are you interested in a career at FM Global specifically?

Technical Discussions

Deeper technical discussions to evaluate skills and knowledge.

What to demonstrate

Deeper technical discussions to evaluate skills and knowledge
Depth in Object-Oriented Programming (OOP)

How to prepare

Answer aloud and timed: Can you describe a time you took ownership of a complex problem?
Answer aloud and timed: Explain the core concepts of Object-Oriented Programming (OOP) and how you apply them in your code.

Behavioral Discussions

Assessment of how candidates will integrate into existing teams.

What to demonstrate

Assessment of how candidates will integrate into existing teams
Depth in Object-Oriented Programming (OOP)

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 discussions above and write down what you would ask to confirm before it.

Final Decision

The hiring team makes a final decision regarding the candidate.

What to demonstrate

The hiring team makes a final decision regarding the candidate
Depth in Object-Oriented Programming (OOP)

How to prepare

Answer aloud and timed: How do you approach debugging a complex issue in a production environment?
Answer aloud and timed: Can you discuss your experience with specific technologies listed in the job description?

Where candidates lose points

Know your resume inside and out

Be prepared to dive deep into any project or technology you have listed. If you mention it, you should be able to explain it.

Practice the STAR method

Behavioral questions are a staple of the FM Global process. Having 3–5 well-prepared stories that highlight your teamwork, problem-solving, and leadership will serve you well.

Be ready for a presentation

Some interview processes require a short presentation on a topic of your choice. Pick something you are passionate about, and ensure you can deliver it clearly within the time limit.

Research the company

Understand what FM Global does as a property insurer. Mentioning their unique focus on engineering-based risk management shows that you have done your homework.

Stay engaged

Even if the process feels slow, maintain a professional and enthusiastic tone in all your communications with HR and hiring managers.

Questions & practice

Walk me through your process for gathering requirements for a new feature.

Medium · Problem Solving and Methodology

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?

What steps do you take to ensure your software meets high quality standards?

Medium · Problem Solving and Methodology

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?

Archive a resource graph without breaking live references or recursing

Medium · graph traversal · topological order · tenant isolation

Resources reference other resources within a tenant; for the largest tenant the reference table holds up to 2,000,000 nodes and 8,000,000 edges. Archiving a resource must archive everything reachable from it that nothing outside the set still references, refuse when a live external referrer exists, and terminate when references form cycles, which they legitimately do. Produce the archive order and the refusal list, targeting O(V+E). Say what stops the traversal crossing a tenant boundary, and why recursion is the wrong control structure at this size.

Approach

Load the subgraph with the tenant predicate on both endpoints of the edge, not only on the side you started from. Scoping the left table alone is the classic cross-tenant leak: one mis-entered edge then pulls another tenant's resources into the traversal and, worse, into the archive.
Traverse iteratively with an explicit stack. A 2,000,000-node graph can hold a chain deep enough to exhaust a native stack in the low tens of thousands of frames, and that failure is a process crash rather than an error you can return.
Treat cycles as data rather than corruption: compute strongly connected components with Tarjan in O(V+E) using its own explicit stack, then condense. The condensation is a DAG, so a topological order over it gives the archive order, and every member of a component archives in one transaction because no order within a cycle is valid.
Decide refusals with reverse edges. A candidate is archivable only if every in-edge originates inside the candidate set, so build the transpose or count in-degrees restricted to the visited set, and emit each blocked resource with the id of the external referrer, which is the only part of the answer an operator can act on.

Follow-up

The graph is read in one query and the archive writes a minute later. What can change in between, and how do you make the write safe?
The candidate set is 400,000 resources. Is that one transaction, and if not, what does a half-finished archive look like to a reader?

Stop tag and share joins from fanning out a page

Medium · join fan-out · semi-joins · many-to-many

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?

Replace offset paging on the resource feed with keyset

Easy · keyset pagination · composite index · sort order

resource holds resource_id, tenant_id, owner_user_id, title, body_ref, version, status ('draft','active','archived','deleted'), created_at, updated_at, deleted_at, with an index on (tenant_id, status, updated_at DESC, resource_id DESC). The listing endpoint returns active resources for one tenant, newest update first, 50 per page, today with LIMIT 50 OFFSET n. Tenants reach page 400 and rows are created while they read. Write the keyset query, define what the cursor carries and how it is encoded, and say which part of the index each predicate uses. Assume PostgreSQL 16.

Approach

Name the two failures separately. OFFSET 20000 makes the server produce and discard 20,000 rows, so page cost grows with depth rather than with page size. Independently, any write that changes how many rows sort above the offset moves the window between two fetches, and the direction decides which anomaly you get: an insert lands at the head of updated_at DESC and pushes already-returned rows down past the boundary, so they are returned a second time; a delete above the offset, or a row whose updated_at is bumped above the cursor, pulls rows up and one is never returned at all. Nothing in the response reveals either.
Write the seek: WHERE tenant_id = $1 AND status = 'active' AND (updated_at, resource_id) < ($2, $3) ORDER BY updated_at DESC, resource_id DESC LIMIT 50. The row-value comparison is one index range rather than a disjunction, and both columns are NOT NULL, which is what makes that comparison well defined.
Map each predicate onto the index: tenant_id and status are equality on the leading columns, (updated_at, resource_id) is the range, and the ORDER BY matches the index order so no Sort node appears and the scan stops after 50 rows. The DESC in the definition only matters for mixed directions — a plain ascending btree on the same columns is read backwards for this query.
Put both sort columns in the cursor and nothing the client can tamper with into another tenant: base64 of (updated_at, resource_id), validated server-side, with tenant_id taken from the principal.

Follow-up

The client asks for 'jump to page 400'. What do you offer instead, and what does the honest version cost?
Sort order becomes user-selectable across four columns. How many indexes is that, and which would you refuse to add?

Explain the core concepts of Object-Oriented Programming (OOP) and how you apply them in your code.

Medium · Technical Proficiency

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 database design and optimization using SQL?

Medium · Technical Proficiency

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?

How do you ensure your code remains maintainable and scalable over time?

Medium · Problem Solving and Methodology

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?

How do you approach debugging a complex issue in a production environment?

Medium · Technical Proficiency

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?

Suggested practice checklist

Built from the rounds and topics Fm global candidates report.

Day 1 — Map the Fm global loop

Write out the reported sequence: Initial Contact, Screening Rounds, Technical Discussions, Behavioral Discussions, Final Decision.
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 5 reported rounds, with the weakest marked.

Day 2 — Work Object-Oriented Programming (OOP)

Spend the session on Object-Oriented Programming (OOP), which Fm global candidates report being tested on.
Write one worked example in Object-Oriented Programming (OOP) and time yourself on it.

Deliverable: One timed worked example in Object-Oriented Programming (OOP).

Day 3 — Work Inheritance

Spend the session on Inheritance, which Fm global candidates report being tested on.
Write one worked example in Inheritance and time yourself on it.

Deliverable: One timed worked example in Inheritance.

Day 4 — Work SQL (Structured Query Language)

Spend the session on SQL (Structured Query Language), which Fm global candidates report being tested on.
Write one worked example in SQL (Structured Query Language) and time yourself on it.

Deliverable: One timed worked example in SQL (Structured Query Language).

Day 5 — Answer out loud: Behavioral and Cultural Fit

Answer aloud, timed: Describe a time you had to manage a difficult project deadline.
Answer aloud, timed: What are your greatest professional strengths and weaknesses?

Deliverable: Spoken answers to 2 reported Behavioral and Cultural Fit question(s), under time.

Day 6 — Answer out loud: Technical Proficiency

Answer aloud, timed: Explain the core concepts of Object-Oriented Programming (OOP) and how you apply them in your code.
Answer aloud, timed: How do you approach database design and optimization using SQL?

Deliverable: Spoken answers to 2 reported Technical Proficiency question(s), under time.

Day 7 — Answer out loud: Problem Solving and Methodology

Answer aloud, timed: Walk me through your process for gathering requirements for a new feature.
Answer aloud, timed: How do you ensure your code remains maintainable and scalable over time?

Deliverable: Spoken answers to 2 reported Problem Solving and Methodology question(s), under time.