A Software Engineer at Not Sure plays a pivotal role in the development and enhancement of software products that are essential to our business operations and customer satisfaction. This position is integral to designing, coding, testing, and maintaining applications that directly impact our users' experience and drive business success. As a Software Engineer, you will contribute to innovative projects, collaborate with cross-functional teams, and leverage cutting-edge technology to solve complex problems. In this role, you will have the opportunity to work on diverse projects that may include building scalable web applications, developing efficient algorithms, and enhancing system architecture. The work of a Software Engineer at Not Sure is not only technically challenging but also strategically significant, as it supports our mission to deliver high-quality, user-friendly products. Expect to engage in a dynamic environment where your contributions will have a direct influence on the success of our initiatives, making it both a rewarding and impactful career choice.
Initial Screening
reportedDiscuss your resume in depth during an initial screening interview.
What to demonstrate
- Discuss your resume in depth during an initial screening interview
- Depth in Data Structures & Algorithms (DSA)
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 Assessments
reportedParticipate in coding tests or system design challenges to evaluate technical abilities.
What to demonstrate
- Participate in coding tests or system design challenges to evaluate technical abilities
- Depth in Data Structures & Algorithms (DSA)
How to prepare
- Answer aloud and timed: Describe a project where you implemented a design pattern and the impact it had.
- Answer aloud and timed: What is the significance of RESTful APIs in web development?
Scenario-Based Questions
reportedAnswer scenario-based questions to demonstrate problem-solving approaches.
What to demonstrate
- Answer scenario-based questions to demonstrate problem-solving approaches
- Depth in Data Structures & Algorithms (DSA)
How to prepare
- Answer aloud and timed: How do you handle version control in your projects?
- Answer aloud and timed: Write a function to reverse a linked list.
Final Interviews
reportedEngage in final interviews that may vary depending on the specific team or role.
What to demonstrate
- Engage in final interviews that may vary depending on the specific team or role
- Depth in Data Structures & Algorithms (DSA)
How to prepare
- Answer aloud and timed: How would you implement a binary search algorithm?
- Answer aloud and timed: Given an array of integers, how do you find the two numbers that add up to a specific target?
PracHub editorial advice for the preparation topics above.
Be Yourself
Authenticity matters at Not Sure. Share your true experiences and perspectives during interviews.
Prepare Real Examples
Use specific examples from your past work to illustrate your skills and problem-solving abilities.
Research the Company
Understand Not Sure's mission, products, and culture to better align your responses with their values.
Practice Coding
Regularly practice coding challenges to sharpen your skills and improve your confidence.
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 C++?
How do you manage memory in C++?
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, how do you find the two numbers that add up to a specific target?
Given an array of integers, how do you 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 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?
Describe how you would optimize an existing algorithm.
Describe how you would optimize an existing 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?
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?
Explain the difference between object-oriented programming and functional programming.
Explain the difference between object-oriented programming and functional 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?
Describe a project where you implemented a design pattern and the impact it had.
Describe a project where you implemented a design pattern and the impact it had.
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 is the significance of RESTful APIs in web development?
What is the significance of RESTful APIs in web development?
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 URL shortening service like Bitly?
How would you design a URL shortening service like Bitly?
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 make for a large-scale online marketplace?
What considerations would you make for a large-scale online marketplace?
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 your approach to designing a microservices architecture.
Describe your approach to 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?
How do you ensure the security of an application you are building?
How do you ensure the security of an application you are building?
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 metrics do you consider when evaluating the performance of a system?
What metrics do you consider when evaluating the performance of a 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?
One customer endpoint stalls deliveries to every other destination
The egress service delivers about 1.5k webhooks/second across 40,000 destinations, with a per-destination concurrency cap of 4 and a 10-second connect-plus-read timeout. Throughput falls to 300/second, queue depth climbs, and p99 delivery latency for unaffected destinations goes from 200 ms to minutes, while the error rate barely moves. One tenant holds 900 destination rows whose URLs share a hostname that now answers in 9.5 seconds. Explain the mechanism with the arithmetic, then give the containment in the order you would apply it.
Approach
- Look at saturation before errors. A flat error rate with collapsing throughput says nothing is failing, things are waiting, so the first signal to pull is in-flight request count or pool wait time rather than the error counter. This is the distinction that decides the whole investigation.
- Group in-flight work by resolved host, not by destination id. The cap is keyed per destination row, so 900 rows sharing one hostname buy 3,600 concurrent slots against a single host, each held for 9.5 seconds. The bulkhead was never a bulkhead for that host, and grouping by the wrong dimension is why the dashboard looked healthy.
- Do the arithmetic in both directions. Required concurrency is arrival rate times latency, so 1.5k/second at 200 ms needs about 300 in flight, which is entirely consumed by 3,600 slow slots; conversely whatever concurrency is left sustains rate equals concurrency divided by 9.5 seconds, which is the 300/second you are seeing. Matching both numbers is what promotes this from a plausible story to the mechanism.
- Explain why the circuit breaker never helped. It opens on consecutive failures, and a 9.5-second response inside a 10-second timeout is a success. Slow is not failing, so an error-rate breaker cannot see this; you need a slow-call ratio, a deadline propagated from the caller's remaining budget, or a concurrency limiter.
Follow-up
- The host recovers to 80 ms. How long does the queue take to drain, and what does the drain do to the recovered host?
- Where should the 10-second timeout number actually come from?
Built from the rounds and topics Not Sure candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Not Sure loop
- Write out the reported sequence: Initial Screening, Technical Assessments, Scenario-Based Questions, Final 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 4 reported rounds, with the weakest marked.
02Work Data Structures & Algorithms (DSA)
- Spend the session on Data Structures & Algorithms (DSA), which Not Sure candidates report being tested on.
- Write one worked example in Data Structures & Algorithms (DSA) and time yourself on it.
Deliverable: One timed worked example in Data Structures & Algorithms (DSA).
03Work SQL
- Spend the session on SQL, which Not Sure candidates report being tested on.
- Write one worked example in SQL and time yourself on it.
Deliverable: One timed worked example in SQL.
04Work Database Management Systems (DBMS)
- Spend the session on Database Management Systems (DBMS), which Not Sure candidates report being tested on.
- Write one worked example in Database Management Systems (DBMS) and time yourself on it.
Deliverable: One timed worked example in Database Management Systems (DBMS).
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the difference between object-oriented programming and functional programming.
- Answer aloud, timed: How do you manage memory in C++?
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 time you faced a significant challenge in a project. How did you handle it?
- Answer aloud, timed: Describe your experience working in a team. What role do you typically take?
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.
How do you handle version control in your projects?
How do you handle version control in your projects?
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 faced a significant challenge in a project. How did you handle it?
Tell me about a time you faced a significant challenge in a project. 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?
Describe your experience working in a team. What role do you typically take?
Describe your experience working in a team. What role do you typically take?
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?
How do you prioritize tasks when working on multiple projects?
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 work in software engineering?
What motivates you to work in software engineering?
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?
How do you handle feedback and criticism?
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
How do you handle version control in your projects?
- 02
Tell me about a time you faced a significant challenge in a project. How did you handle it?
- 03
Describe your experience working in a team. What role do you typically take?
- 04
How do you prioritize tasks when working on multiple projects?
What is the typical interview difficulty for a Software Engineer position at Not Sure?
The interview difficulty is generally moderate to high, with candidates reporting a range of experiences from average to difficult. Preparation in both technical and behavioral areas is essential.
Not Sure Software Engineer candidate reports ↗What differentiates successful candidates at Not Sure?
Successful candidates demonstrate a strong technical foundation, effective communication skills, and the ability to work well within a team. They also show a genuine interest in the company's mission and values.
Not Sure Software Engineer candidate reports ↗What is the culture like at Not Sure?
The culture at Not Sure is collaborative and innovation-driven. Employees are encouraged to share ideas and contribute to projects in a supportive environment.
Not Sure Software Engineer candidate reports ↗How long does the interview process typically take?
The interview process can vary but generally spans a few weeks, including screening, technical assessments, and final interviews.
Not Sure Software Engineer candidate reports ↗Are there opportunities for remote work?
While specific policies may vary by team, Not Sure has embraced flexible work arrangements, including options for remote work.
Not Sure Software Engineer candidate reports ↗How many interview rounds does Not Sure have for a Software Engineer?
The process starts with an Initial Screening, then moves into Technical Assessments, followed by Scenario-Based Questions, and ends with Final Interviews. The exact team and role can make the final interviews vary, but these stages are the core loop described for Software Engineers at Not Sure.
Not Sure Software Engineer candidate reports ↗What is the interview difficulty for Not Sure Software Engineer interviews?
In candidate-reported data for Not Sure Software Engineer interviews, the most common difficulty level is average. Across the reported interviews, difficulty does not skew to the extremes based on what candidates reported.
Not Sure Software Engineer candidate reports ↗What topics are tested in Not Sure Software Engineer interviews?
You should expect questions that cover Data Structures and Algorithms (DSA), SQL, DBMS, and DBMS plus Backend plus DSA integration. Java and Object-Oriented Programming (OOP) are also listed, along with Backend Development and a Project-Based Technical Explanation.
Not Sure Software Engineer candidate reports ↗What coding or system design questions should I expect at Not Sure for Software Engineer?
Technical assessments can include coding tests or system design challenges, plus scenario-based questions that test how you approach real problems. The guide also points to system design themes like designing a URL shortening service, and it includes publicly listed sample prompts such as “RESTful APIs Significance” and “Resolving a High-Stakes Technical Challenge.”
Not Sure Software Engineer candidate reports ↗How does the Not Sure Software Engineer interview loop test resume experience?
During Initial Screening, interviewers discuss your resume in depth, so be ready to walk through your projects and choices. After that, the process shifts toward Technical Assessments and scenario-based questions, which are designed to evaluate both technical ability and your problem-solving approach.
Not Sure Software Engineer candidate reports ↗What is the pay range for a Software Engineer at Not Sure?
Because the only reported pay detail is missing here, you should not rely on a specific salary number until you see an actual job posting for the exact level and location.
Not Sure 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.
- 01Not Sure 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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