As a Software Engineer at Rebellion Defense, you play a pivotal role in transforming the landscape of defense technology through innovative software solutions. This position is critical as it directly impacts the efficacy of products that support national security and intelligence efforts. Your work will contribute to the development of cutting-edge AI applications that enhance operational capabilities and improve decision-making processes in high-stakes environments. In this role, you will engage with complex systems, collaborating with cross-functional teams to address real-world challenges. You will be tasked with designing, developing, and deploying software that is not only technically sophisticated but also aligns with the company’s mission to modernize defense technology. Expect to work on projects that involve significant scale and complexity, where your contributions will have a tangible impact on users and stakeholders. The dynamic nature of Rebellion Defense ensures that you will be continuously challenged, providing an environment where innovation thrives. As part of a culture that values agility and collaboration, you will find opportunities to grow your skills and make meaningful contributions to the defense sector.
Initial Screening Call
reportedA preliminary call to assess the candidate's background and fit for the role.
What to demonstrate
- A preliminary call to assess the candidate's background and fit for the role
- Depth in Problem Solving (Debugging)
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
reportedInterviews that may include coding challenges and behavioral assessments.
What to demonstrate
- Interviews that may include coding challenges and behavioral assessments
- Depth in Problem Solving (Debugging)
How to prepare
- Answer aloud and timed: Describe your experience with [specific technology/tool relevant to the role].
- Answer aloud and timed: Discuss a challenging technical problem you've solved.
PracHub editorial advice for the preparation topics above.
Emphasize your mission alignment
Be explicit about how your values resonate with the mission of Rebellion Defense. This connection can set you apart from other candidates.
Be prepared for ambiguity
Expect questions that may not have clear right or wrong answers. Demonstrating your thought process is often more important than arriving at a definitive solution.
Practice coding under pressure
If technical assessments include coding challenges, practice coding in a timed environment to build confidence and efficiency.
Showcase your projects
Be ready to discuss specific projects you’ve worked on, highlighting your role, the challenges faced, and the outcomes achieved.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a function that reverses a string.
Write a function that reverses a string.
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 set of data, how would you find duplicates efficiently?
Given a set of data, how would you find duplicates efficiently?
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?
Write the update path that detects a concurrent edit
resource carries version INT NOT NULL DEFAULT 1. resource_revision holds revision_id, resource_id, version, actor_user_id, change_kind, patch JSONB, request_id, created_at with UNIQUE (resource_id, version). outbox_event holds aggregate_type, aggregate_id, aggregate_version, event_type, payload, status. A PUT carries the version the client read. Write the exact statements for the single transaction that applies the edit, records the revision and enqueues 'resource.updated', and give the handler's branch on zero affected rows. Then say what PostgreSQL 16 does under READ COMMITTED when two of these updates hit one row at once.
Approach
- One transaction, three writes, no network call inside it: UPDATE resource SET title = $3, version = version + 1, updated_at = now() WHERE resource_id = $1 AND tenant_id = $4 AND version = $2; then INSERT the resource_revision row at version $2 + 1; then INSERT the outbox_event row at the same aggregate_version. The event goes to a table rather than a broker because no transaction spans both.
- Branch on the affected-row count before doing anything else. Zero has three causes — stale version, wrong tenant, row gone — so re-read once and map to 409 carrying the current version, or 404 for an id outside the caller's tenant, which also stops the endpoint confirming that another tenant's id exists.
- State the engine behaviour instead of assuming it. Under READ COMMITTED the second UPDATE blocks on the row lock, and when the first commits PostgreSQL re-evaluates the WHERE clause against the newly committed row, so the version predicate now fails and the statement reports zero rows. Under REPEATABLE READ the identical collision raises SQLSTATE 40001 instead, so the handler must fold both shapes into one conflict response.
- Keep UNIQUE (resource_id, version) even though the predicate already serialises writers. It is what makes a lost update unwritable if any other path ever reaches the revision table, and it converts a logic bug into 23505 rather than into a silently missing history row.
Follow-up
- A client sends the version it read ten minutes ago and the resource has moved three versions. What is in your 409 so it can resolve the conflict without a full re-fetch?
- Two editors, two disjoint fields, no overlap. Does your answer still refuse the second write, and should it?
Replace offset paging on the resource feed with keyset
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 a time you optimized a piece of code. What was the impact?
Explain a time you optimized a piece of code. What was the impact?
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 challenging technical problem you've solved.
Discuss a challenging technical problem you've solved.
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?
What are the key considerations when designing a scalable system?
What are the key considerations when designing a scalable system?
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 would you approach a problem where the requirements are unclear?
How would you approach a problem where the requirements are unclear?
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 tasked with improving an existing application, what steps would you take?
If tasked with improving an existing application, what steps would you take?
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 your thought process when given a new project with tight deadlines.
Describe your thought process when given a new project with tight deadlines.
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 debugging a complex system?
How do you approach debugging a complex system?
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 Rebellion Defense candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Rebellion Defense loop
- Write out the reported sequence: Initial Screening Call, Technical 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 2 reported rounds, with the weakest marked.
02Work Problem Solving (Debugging)
- Spend the session on Problem Solving (Debugging), which Rebellion Defense candidates report being tested on.
- Write one worked example in Problem Solving (Debugging) and time yourself on it.
Deliverable: One timed worked example in Problem Solving (Debugging).
03Work AI Solutions (Machine Learning / AI Engineering)
- Spend the session on AI Solutions (Machine Learning / AI Engineering), which Rebellion Defense candidates report being tested on.
- Write one worked example in AI Solutions (Machine Learning / AI Engineering) and time yourself on it.
Deliverable: One timed worked example in AI Solutions (Machine Learning / AI Engineering).
04Work Complex Problem Solving
- Spend the session on Complex Problem Solving, which Rebellion Defense candidates report being tested on.
- Write one worked example in Complex Problem Solving and time yourself on it.
Deliverable: One timed worked example in Complex Problem Solving.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain a time you optimized a piece of code. What was the impact?
- Answer aloud, timed: How do you approach debugging a complex system?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time when you had to work under pressure. How did you handle it?
- Answer aloud, timed: How do you prioritize tasks when you have multiple deadlines?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
07Answer out loud: Problem-Solving / Case Studies
- Answer aloud, timed: How would you approach a problem where the requirements are unclear?
- Answer aloud, timed: If tasked with improving an existing application, what steps would you take?
Deliverable: Spoken answers to 2 reported Problem-Solving / Case Studies 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 your experience with [specific technology/tool relevant to the role].
Describe your experience with [specific technology/tool relevant to the 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 work under pressure. How did you handle it?
Describe a time when you had to work under pressure. 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 you have multiple deadlines?
How do you prioritize tasks when you have 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?
Tell me about a time you had a disagreement with a teammate. How did you resolve it?
Tell me about a time you had a disagreement with a teammate. How did you resolve 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?
What motivates you to perform at your best?
What motivates you to perform at your best?
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 an instance where you had to lead a project or initiative.
Discuss an instance where you had to lead a project or initiative.
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 your experience with [specific technology/tool relevant to the role].
- 02
Describe a time when you had to work under pressure. How did you handle it?
- 03
How do you prioritize tasks when you have multiple deadlines?
- 04
Tell me about a time you had a disagreement with a teammate. How did you resolve it?
How difficult are the interviews at Rebellion Defense?
The difficulty of interviews can vary, but candidates often describe them as challenging yet fair. Preparation in both technical and behavioral areas is essential for success.
Rebellion Defense Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate strong technical skills, effective problem-solving abilities, and a clear alignment with the company’s mission and values.
Rebellion Defense Software Engineer candidate reports ↗What is the culture like at Rebellion Defense?
The culture is collaborative and innovative, with an emphasis on agility and teamwork. Employees are encouraged to bring new ideas and solutions to the table.
Rebellion Defense Software Engineer candidate reports ↗What is the typical timeline from the initial screen to an offer?
The timeline can range from a few weeks to over a month, depending on the interview process and the number of candidates being considered.
Rebellion Defense Software Engineer candidate reports ↗Are there remote work options available?
While specific policies may vary, Rebellion Defense generally supports flexible work arrangements, including remote work, depending on the role and team dynamics.
Rebellion Defense Software Engineer candidate reports ↗What topics does Rebellion Defense test in interviews?
Rebellion Defense interviews most often cover Technical Writing, Problem Solving (Debugging), Portfolio / Sample Writing, AI Solutions (Machine Learning / AI Engineering), and Writing for Different Audiences (Audience Adaptation). The exact emphasis depends on the specific role you apply for.
Rebellion Defense 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.
- 01Rebellion Defense 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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