As a Software Engineer at KARL STORZ, you play a pivotal role in the development of innovative medical technology solutions that enhance patient care and surgical precision. This position is crucial for ensuring that our software systems are robust, reliable, and seamlessly integrated with our advanced medical devices. You will be part of a collaborative team that works on cutting-edge projects, such as developing software for endoscopic imaging systems or surgical instruments, which have a direct impact on the quality of healthcare delivery. Your contributions will not only involve coding and debugging but also require you to engage in cross-functional teamwork, where your insights on technology can help shape product direction and strategic initiatives. The complexity of projects and the high standards of quality at KARL STORZ make this role both challenging and rewarding, offering you the opportunity to be at the forefront of technological advancements in the medical field.
Phone Screening
reportedInitial phone screening to assess candidate qualifications and fit for the role.
What to demonstrate
- Initial phone screening to assess candidate qualifications and fit for the role
- Depth in C#
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Technical Interviews
reportedOne or more technical interviews conducted either virtually or in person.
What to demonstrate
- One or more technical interviews conducted either virtually or in person
- Depth in C#
How to prepare
- Answer aloud and timed: Can you describe a challenging technical problem you faced and how you resolved it?
- Answer aloud and timed: How do you ensure code quality and maintainability in your projects?
Behavioral Questions
reportedMix of technical and behavioral questions to evaluate skills and cultural fit.
What to demonstrate
- Mix of technical and behavioral questions to evaluate skills and cultural fit
- Depth in C#
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral questions above and write down what you would ask to confirm before it.
Team Engagement
reportedEngagement with various team members, including HR, managers, and peers.
What to demonstrate
- Engagement with various team members
- Including HR, managers, and peers
How to prepare
- Answer aloud and timed: Describe a project where you took the lead. What was the outcome?
- Answer aloud and timed: How do you prioritize your tasks when faced with multiple deadlines?
PracHub editorial advice for the preparation topics above.
Understand the Products
Familiarize yourself with KARL STORZ products and technologies. This knowledge will help you tailor your answers and demonstrate genuine interest in the role.
Practice Behavioral Questions
Prepare for behavioral interview questions by using the STAR method (Situation, Task, Action, Result) to structure your responses.
Ask Insightful Questions
Prepare thoughtful questions to ask your interviewers that reflect your interest in the role and the company’s future direction.
Showcase Continuous Learning
Highlight any ongoing education or certifications relevant to software engineering, as this reflects your commitment to professional growth.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
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 determine if a binary tree is balanced?
How would you determine if a binary tree is balanced?
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 difference between a stack and a queue, and provide examples of their usage.
Explain the difference between a stack and a queue, and provide examples of their usage.
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?
Keep soft-deleted accounts from blocking re-registration
app_user holds user_id, tenant_id, email CITEXT, password_hash (NULL for SSO principals), email_verified_at, auth_version, status ('invited','active','suspended','deactivated'), created_at, updated_at, deleted_at. Two live accounts for one address inside a tenant must be impossible, but an address freed by a soft delete must be reusable, and the same tenant may delete and re-register it repeatedly. Write the uniqueness DDL for PostgreSQL 16, then the equivalent for MySQL 8 where partial indexes do not exist, and say what each permits once three deleted rows already hold that address.
Approach
- Start from what is actually unique: not (tenant_id, email), but (tenant_id, email) among live rows. PostgreSQL says that directly — CREATE UNIQUE INDEX app_user_live_email ON app_user (tenant_id, email) WHERE deleted_at IS NULL. A full constraint over the same two columns burns the address permanently the first time someone deletes an account.
- Keep case-insensitivity in the type or the index, never in the application: CITEXT as given, or UNIQUE (tenant_id, lower(email)) as an expression index where the extension is unavailable. A case-sensitive unique column is exactly how two accounts for one human appear.
- For MySQL 8 the predicate has to move inside the key: add a discriminator column that is a constant 0 while the row is live and is set to user_id on delete, with UNIQUE (tenant_id, email, deleted_marker). Live rows share the constant and still collide; deleted rows differ from each other and stop colliding.
- State the NULL variant and its dependency: leaving the marker NULL for deleted rows also works, because a unique index treats NULLs as distinct — true in MySQL, and true in PostgreSQL only under the default NULLS DISTINCT, which PostgreSQL 15 lets you reverse. Check the polarity against the three existing deleted rows: constant-on-live is what preserves the collision you want, and reversing it silently admits duplicate live accounts.
Follow-up
- A deleted account re-registers with the same address the next day. Do the old resource rows follow the new user_id, and how does the API keep the two principals apart?
- How do you honour an erasure request while resource_revision.actor_user_id still references this table?
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 software development lifecycle you follow.
Explain the software development lifecycle you follow.
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 programming languages are you proficient in, and how have you applied them in previous projects?
What programming languages are you proficient in, and how have you applied them in previous projects?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Can you describe a challenging technical problem you faced and how you resolved it?
Can you describe a challenging technical problem you faced and how you resolved it?
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 ensure code quality and maintainability in your projects?
How do you ensure code quality and maintainability in your projects?
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 experience do you have with version control systems?
What experience do you have with version control systems?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you approach designing a new feature for our software?
How would you approach designing a new feature for our software?
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 situation where you had to make a decision with incomplete information. What was your approach?
Discuss a situation where you had to make a decision with incomplete information. What was your approach?
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?
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 KARL STORZ candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the KARL STORZ loop
- Write out the reported sequence: Phone Screening, Technical Interviews, Behavioral Questions, Team Engagement.
- 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 C#
- Spend the session on C#, which KARL STORZ candidates report being tested on.
- Write one worked example in C# and time yourself on it.
Deliverable: One timed worked example in C#.
03Work Entity Framework (ORM)
- Spend the session on Entity Framework (ORM), which KARL STORZ candidates report being tested on.
- Write one worked example in Entity Framework (ORM) and time yourself on it.
Deliverable: One timed worked example in Entity Framework (ORM).
04Work Angular (Frontend Framework)
- Spend the session on Angular (Frontend Framework), which KARL STORZ candidates report being tested on.
- Write one worked example in Angular (Frontend Framework) and time yourself on it.
Deliverable: One timed worked example in Angular (Frontend Framework).
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the software development lifecycle you follow.
- Answer aloud, timed: What programming languages are you proficient in, and how have you applied them in previous projects?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Tell me about a time you had to work with a difficult team member. How did you handle the situation?
- Answer aloud, timed: Describe a project where you took the lead. What was the outcome?
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 designing a new feature for our software?
- Answer aloud, timed: Imagine a scenario where you receive conflicting requirements from stakeholders. How would you resolve this?
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.
Tell me about a time you had to work with a difficult team member. How did you handle the situation?
Tell me about a time you had to work with a difficult team member. How did you handle the situation?
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 project where you took the lead. What was the outcome?
Describe a project where you took the lead. What was the outcome?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you prioritize your tasks when faced with multiple deadlines?
How do you prioritize your tasks when faced with 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?
Give an example of a time when you had to adapt to a significant change in your work environment.
Give an example of a time when you had to adapt to a significant change in your work environment.
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?
Imagine a scenario where you receive conflicting requirements from stakeholders. How would you resolve this?
Imagine a scenario where you receive conflicting requirements from stakeholders. How would you resolve this?
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
Tell me about a time you had to work with a difficult team member. How did you handle the situation?
- 02
Describe a project where you took the lead. What was the outcome?
- 03
How do you prioritize your tasks when faced with multiple deadlines?
- 04
Give an example of a time when you had to adapt to a significant change in your work environment.
What is the typical interview difficulty for the Software Engineer position?
Most candidates report an average difficulty level during interviews, with a balance of technical and behavioral questions. Preparation in both areas is essential for success.
KARL STORZ Software Engineer candidate reports ↗How much preparation time is advisable before the interview?
Candidates typically spend 2-4 weeks preparing, focusing on technical skills, behavioral examples, and understanding the company's products.
KARL STORZ Software Engineer candidate reports ↗What differentiates successful candidates at KARL STORZ?
Successful candidates demonstrate strong technical skills, effective problem-solving abilities, and a collaborative attitude while aligning with the company’s values.
KARL STORZ Software Engineer candidate reports ↗What is the culture like at KARL STORZ?
KARL STORZ fosters a culture of innovation, teamwork, and quality. Employees are encouraged to contribute ideas and collaborate across disciplines.
KARL STORZ Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The process usually takes 4-6 weeks, encompassing various interview stages and reviews.
KARL STORZ Software Engineer candidate reports ↗What topics does KARL STORZ test in interviews?
KARL STORZ interviews most often cover Stakeholder Management, Communication Skills, Stakeholder Communication, Behavioral Interviewing, and Data Analysis. The exact emphasis depends on the specific role you apply for.
KARL STORZ 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.
- 01KARL STORZ 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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