The role of a Software Engineer at Médecins Sans Frontières (MSF) is vital for developing and maintaining technological solutions that support the organization's mission of providing medical care in underserved regions. As a Software Engineer, you will be at the forefront of creating systems that streamline operations, enhance data management, and improve communication across various teams. This role directly impacts the efficiency and effectiveness of MSF's humanitarian efforts, ensuring that resources are allocated where they are most needed. In this position, you will work on a variety of projects that may involve developing applications for patient management systems, data collection tools, or logistics software that supports field operations. The complexity and scale of these projects present exciting challenges, as you must consider not only technical requirements but also the real-world implications of your work in crisis situations. You will be part of a collaborative team that values innovation and problem-solving, making your contributions critical to the success of MSF’s global initiatives.
Written Questionnaire
reportedCandidates complete a written questionnaire to gauge their technical knowledge and experience.
What to demonstrate
- Candidates complete a written questionnaire to gauge their technical knowledge and experience
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: How do you ensure the quality and maintainability of your code?
- Answer aloud and timed: Describe a project where you implemented a new technology or framework. What challenges did you face?
Cognitive Assessments
reportedCandidates undergo cognitive assessments to evaluate their analytical and problem-solving abilities.
What to demonstrate
- Candidates undergo cognitive assessments to evaluate their analytical and problem-solving abilities
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: How do you approach debugging a complex issue in production?
- Answer aloud and timed: Can you explain the principles of Agile development and how you've applied them in your work?
Technical Discussions
reportedCandidates participate in technical discussions to assess their domain knowledge and expertise.
What to demonstrate
- Candidates participate in technical discussions to assess their domain knowledge and expertise
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: What experience do you have with data security and privacy in software applications?
- Answer aloud and timed: Describe a time when you had to make a quick decision under pressure. What was the outcome?
Behavioral Evaluations
reportedCandidates engage in behavioral evaluations to understand their interpersonal skills and team fit.
What to demonstrate
- Candidates engage in behavioral evaluations to understand their interpersonal skills and team fit
- Depth in Software Engineering (General)
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 evaluations above and write down what you would ask to confirm before it.
PracHub editorial advice for the preparation topics above.
Research the Organization
Familiarize yourself with the mission and values of Médecins Sans Frontières. Understanding the humanitarian context will help you articulate your alignment during interviews.
Prepare for Behavioral Questions
Reflect on your past experiences and be ready to discuss specific examples that illustrate your skills and values, particularly in a team setting.
Practice Coding Skills
If coding is part of the interview process, ensure you practice common algorithms and data structures. Use platforms like LeetCode or HackerRank to sharpen your skills.
Be Authentic
When discussing your motivation for working with MSF, be genuine. Share personal stories or experiences that resonate with the organization’s mission.
Ask Insightful Questions
Prepare thoughtful questions to ask your interviewers about the team dynamics, current projects, and how technology is used to support MSF’s operations.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Solve a coding problem involving data structures and algorithms. Explain your thought process.
Solve a coding problem involving data structures and algorithms. Explain your thought process.
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 optimize a function that calculates the Fibonacci sequence?
How would you optimize a function that calculates the Fibonacci sequence?
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 a function to determine if a given string is a palindrome.
Write a function to determine if a given string is a palindrome.
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 concept of time complexity and provide examples of common complexities.
Explain the concept of time complexity and provide examples of common complexities.
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?
Find version gaps and relay lag with window functions
outbox_event holds event_id, aggregate_type, aggregate_id, aggregate_version, event_type, payload, status ('pending','published','dead'), attempts, created_at, published_at. A projection is missing rows and you must decide whether the relay skipped events or the consumer dropped them. Write three queries over the last seven days: one listing every aggregate_id whose published aggregate_version sequence has a hole, one giving per-day counts with a running total, and one returning the newest published event per aggregate. For each, say where the window function is evaluated relative to WHERE and LIMIT. PostgreSQL 16.
Approach
- Gaps: compute lead(aggregate_version) OVER (PARTITION BY aggregate_id ORDER BY aggregate_version) in a subquery, then filter next_version <> aggregate_version + 1 in the outer query. Window functions are evaluated after WHERE, GROUP BY and HAVING and before the outer ORDER BY and LIMIT, so the predicate cannot sit in the same WHERE clause and PostgreSQL 16 has no QUALIFY.
- Say what the seven-day filter does to the answer: it truncates every partition, so the first row per aggregate has no predecessor inside the window and a hole spanning the boundary is invisible. Widen the window, or join to resource.version as the authority for the true maximum.
- Running total: SELECT date_trunc('day', created_at) AS d, count() AS n, sum(count()) OVER (ORDER BY date_trunc('day', created_at) ROWS UNBOUNDED PRECEDING). An aggregate inside a window call is legal because grouping runs before windowing. The grouping key is unique per row here so ROWS and RANGE agree, but write the frame anyway — over ungrouped rows with tied timestamps the default RANGE frame pulls in every peer row and the total jumps.
- Newest per aggregate: DISTINCT ON (aggregate_id) ... ORDER BY aggregate_id, aggregate_version DESC is the cheap PostgreSQL-only form when an index matches that order; row_number() OVER (PARTITION BY aggregate_id ORDER BY aggregate_version DESC) = 1 is the portable form and needs a subquery for the same evaluation-order reason as the gap query.
Follow-up
- Relay failover redelivers events. Does a duplicate break the gap query, and how would you detect one from this table alone?
- Turn the gap check into a continuous monitor rather than a query someone runs after an incident. What does it watch?
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?
How do you ensure the quality and maintainability of your code?
How do you ensure the quality and maintainability of your code?
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 new technology or framework. What challenges did you face?
Describe a project where you implemented a new technology or framework. What challenges did you face?
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 explain the principles of Agile development and how you've applied them in your work?
Can you explain the principles of Agile development and how you've applied them in your work?
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 data security and privacy in software applications?
What experience do you have with data security and privacy in software applications?
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 system for remote data collection in a resource-limited environment?
How would you approach designing a system for remote data collection in a resource-limited environment?
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 steps would you take to optimize an existing application that is experiencing performance issues?
What steps would you take to optimize an existing application that is experiencing performance issues?
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 a user interface for a medical application, what factors would you consider?
If tasked with improving a user interface for a medical application, what factors would you consider?
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 prioritize features when working on a new product?
How do you prioritize features when working on a new product?
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 the architecture of a system you've built? What were your design considerations?
Can you describe the architecture of a system you've built? What were your design considerations?
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 design a scalable application to handle increasing amounts of data?
How would you design a scalable application to handle increasing amounts of data?
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?
Discuss the trade-offs between microservices and monolithic architecture.
Discuss the trade-offs between microservices and monolithic 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?
What considerations would you have when designing software for use in low-bandwidth environments?
What considerations would you have when designing software for use in low-bandwidth environments?
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 how you would approach integrating a new feature into an existing legacy system.
Describe how you would approach integrating a new feature into an existing legacy system.
Approach
- Say who the caller is and what they do when the call fails halfway.
- Define the identity of a request so a retry cannot double-apply it.
- Separate accepted, pending, failed and confirmed; they are different facts.
- 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 approach debugging a complex issue in production?
How do you approach debugging a complex issue in production?
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 Médecins Sans Frontières candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Médecins Sans Frontières loop
- Write out the reported sequence: Written Questionnaire, Cognitive Assessments, Technical Discussions, Behavioral Evaluations.
- 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 Software Engineering (General)
- Spend the session on Software Engineering (General), which Médecins Sans Frontières candidates report being tested on.
- Write one worked example in Software Engineering (General) and time yourself on it.
Deliverable: One timed worked example in Software Engineering (General).
03Work Technical Subject-Matter Knowledge
- Spend the session on Technical Subject-Matter Knowledge, which Médecins Sans Frontières candidates report being tested on.
- Write one worked example in Technical Subject-Matter Knowledge and time yourself on it.
Deliverable: One timed worked example in Technical Subject-Matter Knowledge.
04Work Technical Interviewing
- Spend the session on Technical Interviewing, which Médecins Sans Frontières candidates report being tested on.
- Write one worked example in Technical Interviewing and time yourself on it.
Deliverable: One timed worked example in Technical Interviewing.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: How do you ensure the quality and maintainability of your code?
- Answer aloud, timed: Describe a project where you implemented a new technology or framework. What challenges did you face?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Problem-Solving / Case Studies
- Answer aloud, timed: Describe a time when you had to make a quick decision under pressure. What was the outcome?
- Answer aloud, timed: How would you approach designing a system for remote data collection in a resource-limited environment?
Deliverable: Spoken answers to 2 reported Problem-Solving / Case Studies question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Give an example of a time you had to work with a difficult team member. How did you handle the situation?
- Answer aloud, timed: What motivates you to work in a humanitarian organization like MSF?
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.
Describe a time when you had to make a quick decision under pressure. What was the outcome?
Describe a time when you had to make a quick decision under pressure. 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?
Give an example of a time you had to work with a difficult team member. How did you handle the situation?
Give an example of 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?
What motivates you to work in a humanitarian organization like MSF?
What motivates you to work in a humanitarian organization like MSF?
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 situation when you had to advocate for a technical solution that was not well-received. What did yo
Describe a situation when you had to advocate for a technical solution that was not well-received. What did you do?
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 of your work?
How do you handle feedback and criticism of your work?
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?
Can you discuss a time when you successfully led a project? What were your key actions?
Can you discuss a time when you successfully led a project? What were your key actions?
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?
Can you discuss a time when you had to refactor code? What improvements did you achieve?
Can you discuss a time when you had to refactor code? What improvements did you achieve?
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 a time when you had to make a quick decision under pressure. What was the outcome?
- 02
Give an example of a time you had to work with a difficult team member. How did you handle the situation?
- 03
What motivates you to work in a humanitarian organization like MSF?
- 04
Describe a situation when you had to advocate for a technical solution that was not well-received. What did you do?
What is the typical difficulty level of the interviews?
The interviews for the Software Engineer position at MSF are generally considered to be of average difficulty. Candidates should expect a mix of technical and behavioral questions, which require solid preparation and a good understanding of both the role and the organization.
Médecins Sans Frontières Software Engineer candidate reports ↗How long does the interview process usually take?
The timeline from initial application to an offer can vary, but candidates typically find that the process spans several weeks. It's important to remain patient and proactive in following up on your application status.
Médecins Sans Frontières Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates often demonstrate a strong alignment with MSF’s values, along with technical proficiency and the ability to communicate effectively with diverse stakeholders. Showing a commitment to humanitarian work and a passion for technology also helps set candidates apart.
Médecins Sans Frontières Software Engineer candidate reports ↗What is the work culture like at Médecins Sans Frontières?
The work culture at MSF is collaborative and mission-driven, with a strong emphasis on teamwork and innovation. Employees are encouraged to share ideas and contribute to solutions that directly impact the organization's humanitarian efforts.
Médecins Sans Frontières Software Engineer candidate reports ↗Are there opportunities for remote work?
While many positions may require on-site presence, MSF has increasingly embraced remote work options, especially for roles that can be effectively performed off-site. Candidates should discuss specific arrangements during their interviews.
Médecins Sans Frontières Software Engineer candidate reports ↗What topics does Médecins Sans Frontières test in interviews?
Médecins Sans Frontières interviews most often cover Competency-Based Interviewing, Project Management, Data Visualization, R Programming, and Business Analysis. The exact emphasis depends on the specific role you apply for.
Médecins Sans Frontières 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.
- 01Médecins Sans Frontières 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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