cswork / libraryOpen practice workspace

Interview guides · Brigham Young University (BYU)

Brigham Young University (BYU) Software Engineer Interview Guide

Brigham Young University (BYU) Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

A Software Engineer at Brigham Young University (BYU) plays a vital role in supporting the university’s mission by building and maintaining the digital infrastructure that serves students, faculty, and administrative staff. This role is not just about writing code; it is about creating efficient, reliable, and user-friendly solutions that directly impact the daily academic and operational life of the campus community. Whether working on web platforms, database management, or internal tooling, you are an integral part of a team dedicated to institutional excellence. You will typically work within a collaborative environment, often interacting with cross-functional teams including professors, administrative staff, and fellow student or full-time developers. The work is characterized by a balance of technical rigor and a mission-driven focus.

This guide is scoped to a Software Engineer candidate at Brigham Young University (BYU).

Focus areas

  • Programming Tests / Coding Challenges
  • SQL
  • Relational Database Design

The Brigham Young University (BYU) interview process

Brigham Young University (BYU) candidates report 5 rounds over 4-6 weeks. The stages below are what candidates describe, not a published process.

Application Review

The process begins with a review of your resume to assess qualifications.

What to demonstrate

  • The process begins with a review of your resume to assess qualifications
  • Depth in Programming Tests / Coding Challenges

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.

Initial Conversation

An initial conversation to gauge your interest and basic qualifications.

What to demonstrate

  • An initial conversation to gauge your interest and basic qualifications
  • Depth in Programming Tests / Coding Challenges

How to prepare

  • Answer aloud and timed: What is your experience with relational database design and writing complex SQL queries?
  • Answer aloud and timed: Are you familiar with frameworks like Ruby on Rails or PHP?

Technical Assessment

A technical round that may include a take-home project or a whiteboard session.

What to demonstrate

  • A technical round that may include a take-home project or a whiteboard session
  • Depth in Programming Tests / Coding Challenges

How to prepare

  • Answer aloud and timed: Can you read a piece of code in a language you aren't an expert in and explain what it does?
  • Answer aloud and timed: Can you solve a problem using pseudo-code?

In-Person/Video Interviews

One or more interviews with managers and peer developers to assess fit.

What to demonstrate

  • One or more interviews with managers and peer developers to assess fit
  • Depth in Programming Tests / Coding Challenges

How to prepare

  • Answer aloud and timed: Walk me through a programming challenge in your preferred language.
  • Answer aloud and timed: How do you approach debugging a complex issue in a web application?

Cultural Fit Assessment

Final stages focus on ensuring you are a good fit for the office culture.

What to demonstrate

  • Final stages focus on ensuring you are a good fit for the office culture
  • Depth in Programming Tests / Coding Challenges

How to prepare

  • Answer aloud and timed: Tell me about a project you worked on and your specific contributions.
  • Answer aloud and timed: What are your career goals and how does this role align with them?

Where candidates lose points

Tailor your resume

Ensure your resume highlights the specific skills mentioned in the job description. Managers often review these to decide who gets an interview.

Prepare for the casual vibe

Don't let the relaxed atmosphere catch you off guard. Stay professional and focused, even if the interview feels more like a conversation.

Be honest about your skills

If you don't know an answer, it is better to explain how you would find the answer rather than guessing.

Research the team

If you know who you are interviewing with, look up their work or the department's recent projects. Showing interest in their specific output goes a long way.

Questions & practice

Can you solve a problem using pseudo-code?

Medium · Problem Solving and Coding

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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 me through a programming challenge in your preferred language.

Medium · Problem Solving and Coding

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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?

Diff a projection against the primary without per-row point reads

Hard · reconciliation · range hashing · throttling

The listing projection has drifted and some rows show a stale version. The primary holds 40,000,000 resource rows across 12,000 tenants while serving 1,200 writes and 14,000 reads per second. The obvious repair, reading each resource row and comparing its version against the projection, is correct and would eventually finish. Explain precisely why it is unacceptable here, then give a diff that finds the differing rows, state its complexity, and make it safe to run against a live primary. Replication lag is usually under 100 ms and is not bounded.

Approach

  1. Quantify the naive cost rather than calling it slow: 40,000,000 point reads at even 0.5 ms each is over five hours serialised, and the only lever is concurrency, which is exactly what you cannot spend. The primary's pool is sized for the write path, and 40,000,000 random reads evict the buffer cache that sustains the 85 percent cache hit rate, so the audit degrades the system it is auditing.
  2. Replace random access with one ordered pass per side. Both sides can be read in (tenant_id, resource_id) order, which is a sequential scan on each and a merge join in O(n) time and O(1) memory. For a dense diff that is the whole answer, and it reads the primary once instead of 40,000,000 times.
  3. For the expected sparse case, compare range hashes instead of rows: partition the key space, compute per range an order-independent aggregate over hash(resource_id, version), compare aggregates, and descend only into ranges that differ. With d differing rows and branching factor B, at most d ranges mismatch per level, so the drill-down examines O(d log_B(n/d)) ranges and reads full rows only in mismatching leaves.
  4. Aggregate with a sum modulo 2^64 or a multiset hash, never XOR. XOR is order-independent but self-cancelling, so two rows wrong in the same way, or a row duplicated on one side, leave the range aggregate matching and the range is declared clean.

Follow-up

  • The diff reports 900 stale rows. How do you decide between patching those rows and rebuilding the projection from resource_revision?
  • Same job, but the projection lives in a search index that cannot be scanned in key order. What changes?

Write the update path that detects a concurrent edit

Medium · optimistic concurrency · transactional outbox · audit history

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

  1. 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.
  2. 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.
  3. 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.
  4. 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?

Explain why the owner filter ignores the listing index

Medium · composite index · query plans · sort elimination

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

  1. 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.
  2. 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.
  3. 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.
  4. 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?

How would you explain the JavaScript event loop?

Medium · Technical and Domain Knowledge

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

Are you familiar with frameworks like Ruby on Rails or PHP?

Medium · Technical and Domain Knowledge

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 read a piece of code in a language you aren't an expert in and explain what it does?

Medium · Technical and Domain Knowledge

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 approach debugging a complex issue in a web application?

Medium · Problem Solving and Coding

Approach

  1. Establish what changed and when, before forming any theory.
  2. Pick a bisection that eliminates candidates whichever way it turns out.
  3. Check the instrumentation before believing the symptom.
  4. 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?

Suggested practice checklist

Built from the rounds and topics Brigham Young University (BYU) candidates report.

Day 1 — Map the Brigham Young University (BYU) loop

  • Write out the reported sequence: Application Review, Initial Conversation, Technical Assessment, In-Person/Video Interviews, Cultural Fit Assessment.
  • 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 5 reported rounds, with the weakest marked.

Day 2 — Work Programming Tests / Coding Challenges

  • Spend the session on Programming Tests / Coding Challenges, which Brigham Young University (BYU) candidates report being tested on.
  • Write one worked example in Programming Tests / Coding Challenges and time yourself on it.

Deliverable: One timed worked example in Programming Tests / Coding Challenges.

Day 3 — Work SQL

  • Spend the session on SQL, which Brigham Young University (BYU) candidates report being tested on.
  • Write one worked example in SQL and time yourself on it.

Deliverable: One timed worked example in SQL.

Day 4 — Work Relational Database Design

  • Spend the session on Relational Database Design, which Brigham Young University (BYU) candidates report being tested on.
  • Write one worked example in Relational Database Design and time yourself on it.

Deliverable: One timed worked example in Relational Database Design.

Day 5 — Answer out loud: Technical and Domain Knowledge

  • Answer aloud, timed: Can you describe your experience with HTML, CSS, and JavaScript?
  • Answer aloud, timed: How would you explain the JavaScript event loop?

Deliverable: Spoken answers to 2 reported Technical and Domain Knowledge question(s), under time.

Day 6 — Answer out loud: Problem Solving and Coding

  • Answer aloud, timed: Can you solve a problem using pseudo-code?
  • Answer aloud, timed: Walk me through a programming challenge in your preferred language.

Deliverable: Spoken answers to 2 reported Problem Solving and Coding question(s), under time.

Day 7 — Answer out loud: Behavioral and Culture Fit

  • Answer aloud, timed: Tell me about a project you worked on and your specific contributions.
  • Answer aloud, timed: What are your career goals and how does this role align with them?

Deliverable: Spoken answers to 2 reported Behavioral and Culture Fit question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

Can you describe your experience with HTML, CSS, and JavaScript?

Medium · Technical and Domain Knowledge

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 is your experience with relational database design and writing complex SQL queries?

Medium · Technical and Domain Knowledge

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Tell me about a project you worked on and your specific contributions.

Medium · Behavioral and Culture Fit

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 are your career goals and how does this role align with them?

Medium · Behavioral and Culture Fit

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 working in a team environment?

Medium · Behavioral and Culture Fit

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 are your interests outside of work? (Be prepared for casual, personal questions).

Medium · Behavioral and Culture Fit

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?