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Thor Solutions Software Engineer Interview Guide

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

The 60-second brief

A Software Engineer at Thor Solutions plays a critical role in supporting the United States Navy and the Department of Defense (DoD). Unlike traditional commercial software roles, engineering at Thor Solutions directly impacts national security, maritime readiness, and tactical capabilities. You will work on mission-critical systems that span across Command, Control, Communications, Computers, Navigation & Electronics (C4N&E), secure DevSecOps pipelines, and complex platform integrations. The software you develop, manage, or deploy is utilized by active-duty sailors, military commanders, and defense analysts.

This guide is scoped to a Software Engineer candidate at Thor Solutions.

Focus areas

  • Local Large Language Models (LLMs)
  • OpenCV
  • Computer Vision Pipeline

The Thor Solutions interview process

Thor Solutions candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Initial Screening Call

A conversation with a recruiter focusing on your professional background, career goals, and eligibility for security clearance.

What to demonstrate

  • A conversation with a recruiter focusing on your professional background, career goals, and eligibility for security clearance
  • Depth in Local Large Language Models (LLMs)

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 Interview

An in-depth interview with hiring managers and senior engineers assessing your domain knowledge, problem-solving skills, and project experience.

What to demonstrate

  • An in-depth interview with hiring managers and senior engineers assessing your domain knowledge, problem-solving skills, and project experience
  • Depth in Local Large Language Models (LLMs)

How to prepare

  • Answer aloud and timed: How do you approach translating high-level operational requirements from Navy stakeholders into concrete technical specifications?
  • Answer aloud and timed: Can you walk us through your experience managing software requirements traceability throughout a project's lifecycle?

Practical Assessment

Depending on the role, you may complete a practical assessment or a system design review.

What to demonstrate

  • Depending on the role, you may complete a practical assessment or a system design review
  • Depth in Local Large Language Models (LLMs)

How to prepare

  • Answer aloud and timed: Describe a time when you had to integrate a modern software application with legacy shipboard hardware. What challenges did you face?
  • Answer aloud and timed: What is your approach to hardening containerized applications (e.g., Docker, Kubernetes) for deployment in air-gapped military networks?

Where candidates lose points

Highlight your DoD experience

If you have previously worked on defense contracts, served in the military, or worked with Navy systems, make sure this experience is prominent on your resume and in your interview answers.

Demonstrate a security-first mindset

Don't just talk about writing code that works. Discuss how you ensure your code is secure, how you handle sensitive data, and your familiarity with cybersecurity standards.

Prepare situational examples

Use the STAR method (Situation, Task, Action, Result) to describe how you have solved complex technical or interpersonal challenges in your past roles.

Show adaptability

Defense projects can experience shifts in requirements, timelines, and priorities. Emphasize your ability to remain productive and focused during periods of change.

Questions & practice

Explain the differences between synchronous and asynchronous programming, and when you would choose one over t

Medium · Software Development & Problem Solving

Explain the differences between synchronous and asynchronous programming, and when you would choose one over the other in a real-time system.

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. 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?

How do you optimize database queries and indexes for applications handling high volumes of transactional data?

Medium · Software Development & Problem Solving

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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 do you design software interfaces to ensure loose coupling and high maintainability over a multi-year life

Medium · Software Development & Problem Solving

How do you design software interfaces to ensure loose coupling and high maintainability over a multi-year lifecycle?

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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?

Hold a per-tenant active cap against concurrent creates

Hard · write skew · isolation levels · constraints

A tenant on the standard plan may hold at most 50 resources with status='active'. The create handler runs SELECT count(*) FROM resource WHERE tenant_id = $1 AND status = 'active', compares to 50, then inserts. Two creates arrive 3 ms apart on different instances and the tenant lands at 51. Name the anomaly, say whether PostgreSQL 16 READ COMMITTED or REPEATABLE READ prevents it and why, then give an implementation that holds the cap at READ COMMITTED with the exact statements. Finally, say what changes when the cap is 'at most one running export per tenant' on job_run.

Approach

  1. Name it: write skew. The two transactions read an overlapping set and write disjoint rows, so there is no row-level conflict for the engine to detect and each commit is individually legal.
  2. Rule out the levels precisely. READ COMMITTED takes a fresh snapshot per statement and takes no lock on the counted rows, so both see 49. PostgreSQL's REPEATABLE READ is snapshot isolation: it removes non-repeatable reads and phantoms within the snapshot but still admits write skew, because the anomaly is not a re-read of a changed row, it is a read of a set that a concurrent transaction invalidates. Only SERIALIZABLE closes it, by tracking the read dependency and aborting one transaction with SQLSTATE 40001 — a guarantee that exists only if the application re-runs the whole transaction from the read.
  3. Convert the set predicate into a single-row conflict: keep tenant.active_resource_count and run UPDATE tenant SET active_resource_count = active_resource_count + 1 WHERE tenant_id = $1 AND active_resource_count < 50 in the same transaction as the INSERT. Zero affected rows is the cap, returned as 409. The row lock serialises the decision at any isolation level, and contention is bounded to one tenant's row — which is also the fair-scheduling unit, unlike a global counter that would convoy every tenant behind one row.
  4. State the cost you just took on: a counter is a second source of truth that can drift, so every path that changes status must adjust it inside the same transaction, and a periodic reconciliation has to exist, with resource_revision as the authority for what the count should have been.

Follow-up

  • A resource moves from archived back to active. Which statements change, and what breaks if the counter update and the status change land in different transactions?
  • The cap becomes plan-dependent and a plan can change mid-month. Where does the number 50 live, and who reads it?

Explain why the owner filter ignores the listing index

Medium · composite index · query plans · sort elimination

The only index on resource is (tenant_id, status, updated_at DESC, resource_id DESC). A new endpoint returns one user's resources across all statuses, newest created first: WHERE tenant_id = $1 AND owner_user_id = $2 ORDER BY created_at DESC LIMIT 20. On a tenant with 2M rows it takes 900 ms and EXPLAIN shows a sort above a large scan. Explain precisely why the existing index cannot serve it, give the index that can, and state which of these the new index still will not help: owner_user_id alone across tenants; the same query ordered by updated_at. PostgreSQL 16.

Approach

  1. Separate the two jobs an index does. For filtering, a composite btree is seekable only on a left prefix, so with no predicate on status the scan can at best range over tenant_id and test owner_user_id per row; PostgreSQL 16 has no btree skip scan to jump the unconstrained column.
  2. For ordering, the index is sorted by (status, updated_at) within a tenant and not by created_at, so the LIMIT cannot stop early: every matching row is read and then sorted. That is the 'Sort Method: top-N heapsort' line, and it is why the plan reads 2M rows to answer with 20.
  3. Derive the replacement from the access path — equality, equality, then the ordering column: CREATE INDEX CONCURRENTLY ON resource (tenant_id, owner_user_id, created_at DESC). The scan seeks to the (tenant, owner) range and walks 20 entries in order, so the Sort node disappears along with the row-read.
  4. Treat INCLUDE (title, status) as conditional, not free. An index-only scan still visits the heap for any row whose page is not marked all-visible, so on a table taking 1.2k writes/second the win depends on autovacuum keeping the visibility map current, and the wider index costs more on every insert.

Follow-up

  • 90% of rows are status='active'. Would a partial index WHERE status = 'active' change your answer, and for which of the three queries?
  • A dashboard runs this for 40 owners in one page load. What changes about the design?

How do you ensure that software designs comply with strict military standards (such as MIL-STD) and cybersecur

Medium · Systems Engineering & DoD Standards

How do you ensure that software designs comply with strict military standards (such as MIL-STD) and cybersecurity requirements?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 translating high-level operational requirements from Navy stakeholders into concrete techn

Medium · Systems Engineering & DoD Standards

How do you approach translating high-level operational requirements from Navy stakeholders into concrete technical specifications?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

What is your approach to hardening containerized applications (e.g., Docker, Kubernetes) for deployment in air

Medium · DevSecOps & Cloud Infrastructure

What is your approach to hardening containerized applications (e.g., Docker, Kubernetes) for deployment in air-gapped military networks?

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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 integrate automated security scanning (SAST/DAST) into a continuous integration/continuous deployme

Medium · DevSecOps & Cloud Infrastructure

How do you integrate automated security scanning (SAST/DAST) into a continuous integration/continuous deployment (CI/CD) pipeline?

Approach

  1. Say who the caller is and what they do when the call fails halfway.
  2. Define the identity of a request so a retry cannot double-apply it.
  3. Separate accepted, pending, failed and confirmed; they are different facts.
  4. 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 manage configuration control and drift across multiple physically separated deployment environments

Medium · DevSecOps & Cloud Infrastructure

How do you manage configuration control and drift across multiple physically separated deployment environments?

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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?

Explain how you would design a resilient backup and disaster recovery strategy for a secure database operating

Medium · DevSecOps & Cloud Infrastructure

Explain how you would design a resilient backup and disaster recovery strategy for a secure database operating in a restricted cloud environment.

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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 strategies do you use to ensure robust error handling and logging in distributed software architectures?

Medium · Software Development & Problem Solving

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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?

Walk us through your process for debugging a critical memory leak in a production environment where you do not

Medium · Software Development & Problem Solving

Walk us through your process for debugging a critical memory leak in a production environment where you do not have direct access to the live system.

Approach

  1. Establish what changed and when, before forming any theory.
  2. Pick a bisection that eliminates candidates whichever way it turns out.
  3. Check the instrumentation before believing the symptom.
  4. 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 Thor Solutions candidates report.

Day 1 — Map the Thor Solutions loop

  • Write out the reported sequence: Initial Screening Call, Technical Interview, Practical Assessment.
  • 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.

Day 2 — Work Local Large Language Models (LLMs)

  • Spend the session on Local Large Language Models (LLMs), which Thor Solutions candidates report being tested on.
  • Write one worked example in Local Large Language Models (LLMs) and time yourself on it.

Deliverable: One timed worked example in Local Large Language Models (LLMs).

Day 3 — Work OpenCV

  • Spend the session on OpenCV, which Thor Solutions candidates report being tested on.
  • Write one worked example in OpenCV and time yourself on it.

Deliverable: One timed worked example in OpenCV.

Day 4 — Work Computer Vision Pipeline

  • Spend the session on Computer Vision Pipeline, which Thor Solutions candidates report being tested on.
  • Write one worked example in Computer Vision Pipeline and time yourself on it.

Deliverable: One timed worked example in Computer Vision Pipeline.

Day 5 — Answer out loud: Systems Engineering & DoD Standards

  • Answer aloud, timed: How do you ensure that software designs comply with strict military standards (such as MIL-STD) and cybersecurity requirements?
  • Answer aloud, timed: Describe your experience with the Risk Management Framework (RMF) and how it influences your software development lifecycle.

Deliverable: Spoken answers to 2 reported Systems Engineering & DoD Standards question(s), under time.

Day 6 — Answer out loud: DevSecOps & Cloud Infrastructure

  • Answer aloud, timed: What is your approach to hardening containerized applications (e.g., Docker, Kubernetes) for deployment in air-gapped military networks?
  • Answer aloud, timed: How do you integrate automated security scanning (SAST/DAST) into a continuous integration/continuous deployment (CI/CD) pipeline?

Deliverable: Spoken answers to 2 reported DevSecOps & Cloud Infrastructure question(s), under time.

Day 7 — Answer out loud: Software Development & Problem Solving

  • Answer aloud, timed: Explain the differences between synchronous and asynchronous programming, and when you would choose one over the other in a real-time system.
  • Answer aloud, timed: How do you optimize database queries and indexes for applications handling high volumes of transactional data?

Deliverable: Spoken answers to 2 reported Software Development & Problem Solving question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

Describe your experience with the Risk Management Framework (RMF) and how it influences your software developm

Medium · Systems Engineering & DoD Standards

Describe your experience with the Risk Management Framework (RMF) and how it influences your software development lifecycle.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?

Can you walk us through your experience managing software requirements traceability throughout a project's lif

Medium · Systems Engineering & DoD Standards

Can you walk us through your experience managing software requirements traceability throughout a project's lifecycle?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 integrate a modern software application with legacy shipboard hardware. What c

Medium · Systems Engineering & DoD Standards

Describe a time when you had to integrate a modern software application with legacy shipboard hardware. What challenges did you face?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 experience with Infrastructure as Code (IaC) tools like Terraform or Ansible in a cloud or hybri

Medium · DevSecOps & Cloud Infrastructure

Describe your experience with Infrastructure as Code (IaC) tools like Terraform or Ansible in a cloud or hybrid environment.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 explain a highly technical software issue to a non-technical military st

Medium · Behavioral & Mission Alignment

Describe a situation where you had to explain a highly technical software issue to a non-technical military stakeholder or government client.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 a situation where a client requests a feature that deviates from the approved system require

Medium · Behavioral & Mission Alignment

How do you handle a situation where a client requests a feature that deviates from the approved system requirements?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 time you had to troubleshoot a critical system failure under tight time constraints, perhaps w

Medium · Behavioral & Mission Alignment

Tell me about a time you had to troubleshoot a critical system failure under tight time constraints, perhaps while deployed or in a field environment.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 manage your workload and maintain focus when project requirements shift rapidly due to changing gov

Medium · Behavioral & Mission Alignment

How do you manage your workload and maintain focus when project requirements shift rapidly due to changing government priorities?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?

Give an example of how you have mentored junior developers or collaborated with cross-functional teams to deli

Medium · Behavioral & Mission Alignment

Give an example of how you have mentored junior developers or collaborated with cross-functional teams to deliver a project on schedule.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?