As a Software Engineer at EY-Parthenon, you operate at the unique intersection of software engineering, digital infrastructure, and strategic consulting. This role is pivotal for driving technology-driven transformations, evaluating digital assets, and advising private equity firms and enterprise clients on software company investments. You will contribute to high-stakes strategic initiatives within specialized groups such as the Software Strategy Group and Digital Infrastructure teams, directly influencing product roadmaps, commercial due diligence, and growth platforms. Your day-to-day impact involves analyzing complex software systems, assessing digital portfolios, and engineering scalable solutions that address high-level business challenges. Whether you are conducting technical due diligence on a target acquisition or architecting modern cloud solutions, your work bridges the gap between technical execution and strategic business vision. The role demands both deep technical proficiency and the ability to communicate intricate software concepts to non-technical stakeholders and executive leadership. Candidates entering this role can expect a fast-paced, intellectually demanding environment where analytical rigor is matched by collaborative problem-solving. You will work alongside sharp, supportive professionals who value both technical curiosity and strong interpersonal dynamics.
Recruiter Screen
reportedInitial screening by a recruiter to assess candidate fit and qualifications.
What to demonstrate
- Initial screening by a recruiter to assess candidate fit and qualifications
- Depth in Case Interviews
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.
Final Round/Superday
reportedComprehensive interviews with multiple professionals to evaluate advanced case-solving and strategic thinking.
What to demonstrate
- Comprehensive interviews with multiple professionals to evaluate advanced case-solving and strategic thinking
- Depth in Case Interviews
How to prepare
- Answer aloud and timed: Describe a time when you collaborated with cross-functional team members to overcome an ambiguous technical challenge.
- Answer aloud and timed: Discuss your genuine passion for technology and how you keep your engineering skills sharp.
PracHub editorial advice for the preparation topics above.
Embrace the conversational case format
Expect cases that lack a rigid, pre-determined structure; view them as an interactive discussion rather than a test.
Structure your thoughts out loud
When presented with complex graphs or figures, vocalize your hypotheses and analytical steps so the interviewer can follow your reasoning.
Connect technical details to business value
Always tie your engineering insights back to what they mean for a company's market viability, scalability, or investment potential.
Ask insightful questions
Demonstrate genuine interest in the team's work by asking how they measure success and how their advisory projects impact private equity clients.
Refine your technical storytelling
Prepare concise, impactful narratives about your hardest engineering projects, focusing on your personal contributions and problem-solving methodology.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Analyze a software company in a private equity firm's current portfolio and recommend strategic growth adjustm
Analyze a software company in a private equity firm's current portfolio and recommend strategic growth adjustments.
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?
Interpret a series of complex, data-heavy graphs and figures to evaluate a target software company's market po
Interpret a series of complex, data-heavy graphs and figures to evaluate a target software company's market positioning.
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?
Structure a commercial due diligence assessment for a software enterprise looking to scale its digital infrast
Structure a commercial due diligence assessment for a software enterprise looking to scale its digital infrastructure.
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?
Walk through a prompt engineering case study to evaluate modern software deployment efficiencies.
Walk through a prompt engineering case study to evaluate modern software deployment efficiencies.
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?
Evaluate a target company's technology stack under tight time constraints and present your structural findings
Evaluate a target company's technology stack under tight time constraints and present your structural findings to senior leadership.
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 why you want to join this specific group and how you evaluate your professional fit within our culture
Explain why you want to join this specific group and how you evaluate your professional fit within our culture.
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
Explain why the owner filter ignores the listing index
The only index on resource is (tenant_id, status, updated_at DESC, resource_id DESC). A new endpoint returns one user's resources across all statuses, newest created first: WHERE tenant_id = $1 AND owner_user_id = $2 ORDER BY created_at DESC LIMIT 20. On a tenant with 2M rows it takes 900 ms and EXPLAIN shows a sort above a large scan. Explain precisely why the existing index cannot serve it, give the index that can, and state which of these the new index still will not help: owner_user_id alone across tenants; the same query ordered by updated_at. PostgreSQL 16.
Approach
- Separate the two jobs an index does. For filtering, a composite btree is seekable only on a left prefix, so with no predicate on status the scan can at best range over tenant_id and test owner_user_id per row; PostgreSQL 16 has no btree skip scan to jump the unconstrained column.
- For ordering, the index is sorted by (status, updated_at) within a tenant and not by created_at, so the LIMIT cannot stop early: every matching row is read and then sorted. That is the 'Sort Method: top-N heapsort' line, and it is why the plan reads 2M rows to answer with 20.
- Derive the replacement from the access path — equality, equality, then the ordering column: CREATE INDEX CONCURRENTLY ON resource (tenant_id, owner_user_id, created_at DESC). The scan seeks to the (tenant, owner) range and walks 20 entries in order, so the Sort node disappears along with the row-read.
- Treat INCLUDE (title, status) as conditional, not free. An index-only scan still visits the heap for any row whose page is not marked all-visible, so on a table taking 1.2k writes/second the win depends on autovacuum keeping the visibility map current, and the wider index costs more on every insert.
Follow-up
- 90% of rows are status='active'. Would a partial index WHERE status = 'active' change your answer, and for which of the three queries?
- A dashboard runs this for 40 owners in one page load. What changes about the design?
Discuss the core components of modern digital infrastructure and how you design systems for high availability.
Discuss the core components of modern digital infrastructure and how you design systems for high availability.
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?
Explain how you approach technical due diligence when assessing a third-party software product.
Explain how you approach technical due diligence when assessing a third-party software 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?
Walk through how you would optimize a legacy software pipeline to meet modern cloud-native standards.
Walk through how you would optimize a legacy software pipeline to meet modern cloud-native standards.
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?
Listing latency scales with page size, not with filters
The tenant listing endpoint reads resource filtered by tenant_id and status, ordered by updated_at DESC, and returns each row plus the owner's display name from app_user and the actor of that resource's latest resource_revision. p99 is 55 ms at 10 rows per page and 1.4 s at 200. Database telemetry shows 401 statements per request, each under 1 ms, and nothing in the slow-query log. Diagnose the cause and give the fix, stating the statement count per request and the p99 you expect afterwards.
Approach
- Read the counters before forming a theory. 401 statements for 200 rows is one driver query plus two per row, and sub-millisecond execution with an empty slow-query log rules out a bad plan. The time is round trips, which is why it is invisible in every per-query metric and scales with rows returned rather than with filter selectivity.
- Name the two per-row statements from their normalised text: a single-row app_user lookup by user_id, and a resource_revision lookup by resource_id ordered by version DESC LIMIT 1. Confirm by dropping those two response fields and watching the statement count fall to one. That locates the calls in the serialisation layer, not the repository.
- Check that the arithmetic accounts for the whole gap. Measure one round trip to the replica in isolation; 400 trips at roughly 3 ms of network plus 0.2 ms of execution is about 1.3 s on top of a 55 ms baseline, which matches. If the multiplication had fallen short, the N+1 would only be part of the story and you would keep looking.
- Batch both lookups. Collect owner_user_ids and resource_ids from the driver query, then issue WHERE tenant_id = $1 AND user_id = ANY($2) for the users, and PostgreSQL's SELECT DISTINCT ON (resource_id) ... WHERE resource_id = ANY($2) ORDER BY resource_id, version DESC for the latest revision, which the UNIQUE (resource_id, version) index serves directly. On an engine without DISTINCT ON, use a lateral join or a row_number window. Three statements per request at any page size.
Follow-up
- The page size is capped at 200 today. What breaks first if it is raised to 2,000, and is it still this bug?
- How do you stop the next N+1 from reaching production, given that no individual query is slow and the endpoint's tests pass?
Built from the rounds and topics EY-Parthenon candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the EY-Parthenon loop
- Write out the reported sequence: Recruiter Screen, Final Round/Superday.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 2 reported rounds, with the weakest marked.
02Work Case Interviews
- Spend the session on Case Interviews, which EY-Parthenon candidates report being tested on.
- Write one worked example in Case Interviews and time yourself on it.
Deliverable: One timed worked example in Case Interviews.
03Work Behavioral Interviewing
- Spend the session on Behavioral Interviewing, which EY-Parthenon candidates report being tested on.
- Write one worked example in Behavioral Interviewing and time yourself on it.
Deliverable: One timed worked example in Behavioral Interviewing.
04Work Problem Solving / Analytical Thinking
- Spend the session on Problem Solving / Analytical Thinking, which EY-Parthenon candidates report being tested on.
- Write one worked example in Problem Solving / Analytical Thinking and time yourself on it.
Deliverable: One timed worked example in Problem Solving / Analytical Thinking.
05Answer out loud: Behavioral & Team Fit
- Answer aloud, timed: Assess how your past professional background aligns with the specific team and responsibilities at EY-Parthenon.
- Answer aloud, timed: Walk through your hardest technical project and explain how you successfully solved the core problems involved.
Deliverable: Spoken answers to 2 reported Behavioral & Team Fit question(s), under time.
06Answer out loud: Case Studies & Analytical Problem Solving
- Answer aloud, timed: Analyze a software company in a private equity firm's current portfolio and recommend strategic growth adjustments.
- Answer aloud, timed: Interpret a series of complex, data-heavy graphs and figures to evaluate a target software company's market positioning.
Deliverable: Spoken answers to 2 reported Case Studies & Analytical Problem Solving question(s), under time.
07Answer out loud: Technical & Domain Knowledge
- Answer aloud, timed: Discuss the core components of modern digital infrastructure and how you design systems for high availability.
- Answer aloud, timed: Explain how you approach technical due diligence when assessing a third-party software product.
Deliverable: Spoken answers to 2 reported Technical & Domain Knowledge 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.
Assess how your past professional background aligns with the specific team and responsibilities at EY-Partheno
Assess how your past professional background aligns with the specific team and responsibilities at EY-Parthenon.
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?
Walk through your hardest technical project and explain how you successfully solved the core problems involved
Walk through your hardest technical project and explain how you successfully solved the core problems involved.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe a time when you collaborated with cross-functional team members to overcome an ambiguous technical ch
Describe a time when you collaborated with cross-functional team members to overcome an ambiguous technical challenge.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Discuss your genuine passion for technology and how you keep your engineering skills sharp.
Discuss your genuine passion for technology and how you keep your engineering skills sharp.
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 with data-heavy engineering challenges and how you ensure system scalability.
Describe your experience with data-heavy engineering challenges and how you ensure system scalability.
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
Assess how your past professional background aligns with the specific team and responsibilities at EY-Parthenon.
- 02
Walk through your hardest technical project and explain how you successfully solved the core problems involved.
- 03
Describe a time when you collaborated with cross-functional team members to overcome an ambiguous technical challenge.
- 04
Discuss your genuine passion for technology and how you keep your engineering skills sharp.
How difficult is the interview process at EY-Parthenon?
The process is moderately challenging, balancing standard software engineering concepts with rigorous business case studies. While the interviewers are known for being exceptionally kind and conversational, the analytical bar for structuring due diligence problems remains high.
EY-Parthenon Software Engineer candidate reports ↗How much preparation time do I need?
Most candidates benefit from 3 to 4 weeks of focused preparation, dedicating time to both practicing unstructured case studies and reviewing core software architecture principles. Tailoring your behavioral stories to highlight complex technical problem-solving is also essential.
EY-Parthenon Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates stand out by demonstrating intellectual curiosity, remaining calm when interpreting graph-heavy data, and communicating their thought process clearly. Being genuinely conversational and collaborative with your interviewers is a major differentiator.
EY-Parthenon Software Engineer candidate reports ↗What is the typical timeline from screen to offer?
The process is designed to move quickly, often taking less than two weeks from the initial HR screening call through the final superday round. Prompt communication and scheduling flexibility will help you keep this efficient pace.
EY-Parthenon Software Engineer candidate reports ↗Are remote or hybrid work options available?
Location flexibility depends on the specific hub office (such as Boston, New York, or Los Angeles) and the team's client-facing commitments. Be sure to discuss specific hybrid expectations with your recruiter during the initial screening call.
EY-Parthenon Software Engineer candidate reports ↗What topics does EY-Parthenon test in interviews?
EY-Parthenon interviews most often cover Quantitative Reasoning, Behavioral Interviewing, Python, Estimation & Back-of-the-Envelope Calculations, and SQL. The exact emphasis depends on the specific role you apply for.
EY-Parthenon 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.
- 01EY-Parthenon 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
Explore related engineering environments and compare the preparation focus.
Vercel Software Engineer Interview Guide
Debugging practice for Vercel software engineer prep built on a reproduction you trust, narrowing to the smallest failing input, and changing one variable per run so the result stays attributable.
Together Ai Software Engineer Interview Guide
Failure-handling practice for Together Ai software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
Lambda Software Engineer Interview Guide
Failure-handling practice for Lambda software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
CoreWeave Software Engineer Interview Guide
Failure-handling practice for CoreWeave software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.