The role of a Software Engineer at Educational Testing Service (Ets) is pivotal in shaping the tools and technologies that support educational assessment and improvement. You will be responsible for developing and maintaining software solutions that ensure the integrity and effectiveness of educational testing services. This position directly influences how students and educators interact with assessment tools, contributing to the overall mission of enhancing learning outcomes through innovative technology. As a Software Engineer, you will work on diverse projects that address complex problems in educational technology, collaborating with cross-functional teams to ensure products are scalable, reliable, and user-friendly. The work you do will not only impact the efficiency of the testing processes but also enhance user experiences for both educators and students, making your role critical in driving the future of education.
Screening Phase
reportedInitial evaluation of candidates to assess their qualifications and fit for the role.
What to demonstrate
- Initial evaluation of candidates to assess their qualifications and fit for the role
- Depth in Java
How to prepare
- Answer aloud and timed: Explain the differences between Java and C#.
- Answer aloud and timed: What do you understand by multithreading, and how have you implemented it in your projects?
Technical Interviews
reportedMultiple rounds focusing on coding challenges and system design discussions.
What to demonstrate
- Multiple rounds focusing on coding challenges and system design discussions
- Depth in Java
How to prepare
- Answer aloud and timed: Describe the Java Collections Framework. What are its advantages?
- Answer aloud and timed: How do you handle exceptions in Java?
Behavioral Assessments
reportedInterviews that evaluate candidates' experiences and cultural fit within the organization.
What to demonstrate
- Interviews that evaluate candidates' experiences and cultural fit within the organization
- Depth in Java
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 assessments above and write down what you would ask to confirm before it.
Final Discussions
reportedConcluding discussions with management to finalize the interview process.
What to demonstrate
- Concluding discussions with management to finalize the interview process
- Depth in Java
How to prepare
- Answer aloud and timed: What considerations would you make for database design in a high-traffic educational platform?
- Answer aloud and timed: Discuss how you would approach designing a microservices architecture.
PracHub editorial advice for the preparation topics above.
Know your resume
Be prepared to discuss all aspects of your experience in detail, as many questions will stem from your past work.
Practice coding
Familiarize yourself with common coding challenges and algorithms, as technical interviews may include live coding exercises.
Understand the mission
Research the mission and values of Educational Testing Service (Ets) to articulate why you are a good fit for the organization.
Ask questions
Prepare thoughtful questions to ask your interviewers about the team, projects, and company culture to demonstrate your interest and engagement.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
What do you understand by multithreading, and how have you implemented it in your projects?
What do you understand by multithreading, and how have you implemented it in your projects?
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 string in Java.
Write a function to reverse a string in Java.
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?
Can you solve this problem using recursion?
Can you solve this problem using recursion?
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?
What is the time complexity of your solution, and how can it be optimized?
What is the time complexity of your solution, and how can it be optimized?
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?
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?
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 the differences between Java and C#.
Explain the differences between Java and C#.
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 the Java Collections Framework. What are its advantages?
Describe the Java Collections Framework. What are its advantages?
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 discuss a software project where you utilized design patterns?
Can you discuss a software project where you utilized design patterns?
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 scalable web application for educational assessments?
How would you design a scalable web application for educational assessments?
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 database design in a high-traffic educational platform?
What considerations would you make for database design in a high-traffic educational platform?
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 how you would approach designing a microservices architecture.
Discuss how you would approach 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?
What are the key differences between monolithic and microservices architecture?
What are the key differences between monolithic and 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?
If you were tasked with reducing the load time of an application, what steps would you take?
If you were tasked with reducing the load time of an 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?
How would you approach a situation where a critical bug was found just before a product launch?
How would you approach a situation where a critical bug was found just before a product launch?
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?
Given a scenario where user feedback indicates confusion with a feature, how would you address it?
Given a scenario where user feedback indicates confusion with a feature, how would you address 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?
Edge instances grow 400 MB per hour until the nightly restart
Edge API instances start at 700 MB resident and grow about 400 MB/hour; a nightly rolling restart has hidden it for weeks. Growth continues unchanged when request rate halves overnight, p99 degrades in the last hours before an instance is recycled, and heap used immediately after a forced full GC rises monotonically. The service holds no product state. Name the discriminating measurement that separates the plausible causes, give the most likely cause, and give the fix and how you would verify it.
Approach
- Separate resident memory from live heap first, because they fail differently. Resident size can grow from fragmentation, native buffers or thread stacks while the heap is flat; heap used after a full GC rising monotonically is the measurement that says objects are reachable and not being released. You already have it, so this is retention, not fragmentation, and that closes off half the candidate list.
- Use the rate's independence from traffic as the discriminator. Growth that continues at half the request rate rules out per-request objects that are merely slow to collect and points at a structure that grows with distinct values observed rather than with call volume. Write the candidates that have that property: a metrics registry keyed on a high-cardinality label, an unevicted cache, an interner, a per-key lock map.
- Take two heap snapshots an hour apart and diff by retained size, reading the dominator tree, not by allocation count or instance count. Expect one root holding a map with millions of entries, then follow the reference chain to the code that inserts and never removes. Allocation profilers point at churn, which is the wrong signal here.
- The candidate that fits this service is an observability label carrying an identifier, such as a request path recorded before templating so that /v1/resources/48213 becomes its own metric series. That grows with distinct ids seen, is independent of rate, and explains the late p99 degradation, since GC cost rises with the size of the live set.
Follow-up
- Post-GC heap is now flat but resident size still creeps. What are you looking at, and does it matter?
- How would you have detected this before an OOM, given the nightly restart masked the trend?
Built from the rounds and topics Educational Testing Service (Ets) candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Educational Testing Service (Ets) loop
- Write out the reported sequence: Screening Phase, Technical Interviews, Behavioral Assessments, Final Discussions.
- 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 Java
- Spend the session on Java, which Educational Testing Service (Ets) candidates report being tested on.
- Write one worked example in Java and time yourself on it.
Deliverable: One timed worked example in Java.
03Work Coding Questions (problem solving)
- Spend the session on Coding Questions (problem solving), which Educational Testing Service (Ets) candidates report being tested on.
- Write one worked example in Coding Questions (problem solving) and time yourself on it.
Deliverable: One timed worked example in Coding Questions (problem solving).
04Work React Hooks
- Spend the session on React Hooks, which Educational Testing Service (Ets) candidates report being tested on.
- Write one worked example in React Hooks and time yourself on it.
Deliverable: One timed worked example in React Hooks.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the differences between Java and C#.
- Answer aloud, timed: What do you understand by multithreading, and how have you implemented it in your projects?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: System Design / Architecture
- Answer aloud, timed: How would you design a scalable web application for educational assessments?
- Answer aloud, timed: What considerations would you make for database design in a high-traffic educational platform?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a challenging project you worked on and how you overcame the obstacles.
- Answer aloud, timed: How do you handle conflict within a team?
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 exceptions in Java?
How do you handle exceptions in Java?
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 challenging project you worked on and how you overcame the obstacles.
Describe a challenging project you worked on and how you overcame the obstacles.
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 conflict within a team?
How do you handle conflict within a team?
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 give an example of a time when you had to lead a project?
Can you give an example of a time when you had to lead a project?
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 the field of educational technology?
What motivates you to work in the field of educational technology?
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 exceptions in Java?
- 02
Describe a challenging project you worked on and how you overcame the obstacles.
- 03
How do you handle conflict within a team?
- 04
Can you give an example of a time when you had to lead a project?
How difficult are the interviews at Educational Testing Service (Ets)?
The interviews are generally considered to be of average difficulty. Expect a mix of technical and behavioral questions aimed at assessing both your skills and cultural fit.
Educational Testing Service (Ets) Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates typically demonstrate not only strong technical skills but also a clear alignment with the organization's mission and values, along with effective communication abilities.
Educational Testing Service (Ets) Software Engineer candidate reports ↗What is the culture like at Educational Testing Service (Ets)?
The culture values collaboration, innovation, and a commitment to educational improvement. Employees are encouraged to share ideas and contribute to meaningful projects.
Educational Testing Service (Ets) Software Engineer candidate reports ↗How long does the interview process typically take?
The interview process can take several weeks, often involving multiple rounds and different stages, including initial screenings and technical assessments.
Educational Testing Service (Ets) Software Engineer candidate reports ↗Is remote work an option?
While specific policies may vary, Educational Testing Service (Ets) has been known to offer flexible working arrangements, including remote options, depending on the role and team.
Educational Testing Service (Ets) Software Engineer candidate reports ↗What topics does Educational Testing Service (Ets) test in interviews?
Educational Testing Service (Ets) interviews most often cover Statistical Analysis, Problem Solving, Stakeholder Management, Data Visualization, and Experimentation / A-B Testing. The exact emphasis depends on the specific role you apply for.
Educational Testing Service (Ets) 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.
- 01Educational Testing Service (Ets) 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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