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REI (Recreational Equipment Inc.) Software Engineer Interview Guide

REI (Recreational Equipment Inc.) Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

A Software Engineer at REI (Recreational Equipment Inc.) plays a pivotal role in bridging the gap between the physical outdoors and digital commerce. As a member of the co-op, you are not just building software for a standard corporation; you are engineering platforms that support millions of active members who value sustainability, community, and outdoor stewardship. The systems you build power everything from the high-traffic e-commerce engine on REI.com and the mobile application to complex inventory management, supply chain logistics, and membership reward programs. The impact of this role is massive. REI (Recreational Equipment Inc.) relies heavily on its digital presence to drive its co-op business model, where member engagement and seamless digital touchpoints are critical to long-term loyalty.

This guide is scoped to a Software Engineer candidate at REI (Recreational Equipment Inc.).

Focus areas

  • Data structures
  • Communication skills
  • High-level vs. deep-dive technical explanations

The REI (Recreational Equipment Inc.) interview process

REI (Recreational Equipment Inc.) candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Recruiter Phone Screen

Initial call focusing on your background and high-level fit, often using a checklist of technologies.

What to demonstrate

  • Initial call focusing on your background and high-level fit, often using a checklist of technologies
  • Depth in Data structures

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.

Hiring Manager Call

Get-to-know-you call exploring your past projects and career goals.

What to demonstrate

  • Get-to-know-you call exploring your past projects and career goals
  • Depth in Data structures

How to prepare

  • Prepare two projects you led end to end, each with the decision you owned and what it cost.
  • Have three questions about the team's roadmap and how success is measured in the first six months.

Coding Exercise or Technical Screen

Complete a take-home coding exercise or undergo a technical phone screen with a developer.

What to demonstrate

  • Complete a take-home coding exercise or undergo a technical phone screen with a developer
  • Depth in Data structures

How to prepare

  • Answer aloud and timed: Explain the internal workings of a HashMap, including collision resolution.
  • Answer aloud and timed: How would you design a relational database schema for a retail inventory system?

Panel Interviews

Series of interviews with multiple pairs of engineers and stakeholders covering coding, system design, and behavioral scenarios.

What to demonstrate

  • Series of interviews with multiple pairs of engineers and stakeholders covering coding, system design, and behavioral scenarios
  • Depth in Data structures

How to prepare

  • Answer aloud and timed: Explain the trade-offs between SQL and NoSQL databases when handling transactional user data.
  • Answer aloud and timed: How do you handle database connection pooling in a high-concurrency environment?

Where candidates lose points

Be specific about the role details

Some candidates have noted that online job descriptions do not always perfectly align with the daily realities of the team. Do not hesitate to ask highly specific questions during your hiring manager screen about the exact tech stack, daily responsibilities, and team expectations.

Practice step-by-step explanations

When describing your past projects or answering technical questions, practice breaking down the process into granular steps. Avoid skipping over the details of how data flows through your services or how memory is managed.

Showcase your collaborative nature

Use "we" in addition to "I" when discussing past achievements. Emphasize how you worked with your team to overcome challenges, mentored others, or aligned with product stakeholders.

Perfect your "Why REI?" story

Do not treat this as a generic behavioral question. Spend time researching the co-op's unique business model, its community initiatives, and why its mission resonates with you personally. An authentic connection to the co-op's values is a major differentiator.

Questions & practice

How do you implement and optimize a basic binary search tree?

Medium · Core Programming & Data Structures

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?

Explain the difference between an interface and an abstract class in Java, and when you would use each.

Medium · Core Programming & Data Structures

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?

What are the memory management implications of garbage collection in a JVM environment?

Medium · Core Programming & Data Structures

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. 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?

Walk me through how you would reverse a linked list, both iteratively and recursively.

Medium · Core Programming & Data Structures

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?

Explain the internal workings of a HashMap, including collision resolution.

Medium · Core Programming & Data Structures

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?

Explain the trade-offs between SQL and NoSQL databases when handling transactional user data.

Medium · System Design & Database Concepts

Approach

  1. Name the grain you start from and join outward from it.
  2. Check whether any join is one-to-many before aggregating, or the sums inflate.
  3. Say which index the query would use, and what makes it unusable.
  4. 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?

Stop tag and share joins from fanning out a page

Medium · join fan-out · semi-joins · many-to-many

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

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

How would you design a relational database schema for a retail inventory system?

Medium · System Design & Database Concepts

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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 build a caching layer to reduce latency on a frequently accessed product catalog.

Medium · System Design & Database Concepts

Approach

  1. Fix the scope first: who calls this, how often, and what they do when it fails.
  2. Name the read and write paths separately; they rarely have the same bottleneck.
  3. Choose a partition key and say what query it makes expensive.
  4. 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?

Listing latency scales with page size, not with filters

Easy · n+1 · latency · query batching

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

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

Suggested practice checklist

Built from the rounds and topics REI (Recreational Equipment Inc.) candidates report.

Day 1 — Map the REI (Recreational Equipment Inc.) loop

  • Write out the reported sequence: Recruiter Phone Screen, Hiring Manager Call, Coding Exercise or Technical Screen, Panel Interviews.
  • 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.

Day 2 — Work Data structures

  • Spend the session on Data structures, which REI (Recreational Equipment Inc.) candidates report being tested on.
  • Write one worked example in Data structures and time yourself on it.

Deliverable: One timed worked example in Data structures.

Day 3 — Work Communication skills

  • Spend the session on Communication skills, which REI (Recreational Equipment Inc.) candidates report being tested on.
  • Write one worked example in Communication skills and time yourself on it.

Deliverable: One timed worked example in Communication skills.

Day 4 — Work High-level vs. deep-dive technical explanations

  • Spend the session on High-level vs. deep-dive technical explanations, which REI (Recreational Equipment Inc.) candidates report being tested on.
  • Write one worked example in High-level vs. deep-dive technical explanations and time yourself on it.

Deliverable: One timed worked example in High-level vs. deep-dive technical explanations.

Day 5 — Answer out loud: Core Programming & Data Structures

  • Answer aloud, timed: How do you implement and optimize a basic binary search tree?
  • Answer aloud, timed: Explain the difference between an interface and an abstract class in Java, and when you would use each.

Deliverable: Spoken answers to 2 reported Core Programming & Data Structures question(s), under time.

Day 6 — Answer out loud: System Design & Database Concepts

  • Answer aloud, timed: How would you design a relational database schema for a retail inventory system?
  • Answer aloud, timed: Explain the trade-offs between SQL and NoSQL databases when handling transactional user data.

Deliverable: Spoken answers to 2 reported System Design & Database Concepts question(s), under time.

Day 7 — Answer out loud: Behavioral, Teamwork & "Why REI?"

  • Answer aloud, timed: Why do you want to work for REI (Recreational Equipment Inc.) specifically?
  • Answer aloud, timed: Describe a time when you had a disagreement with a technical lead or product manager. How did you resolve it?

Deliverable: Spoken answers to 2 reported Behavioral, Teamwork & "Why REI?" question(s), under time.

Behavioural preparation

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

How do you handle database connection pooling in a high-concurrency environment?

Medium · System Design & Database Concepts

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?

Why do you want to work for REI (Recreational Equipment Inc.) specifically?

Medium · Behavioral, Teamwork & "Why REI?"

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?

Describe a time when you had a disagreement with a technical lead or product manager. How did you resolve it?

Medium · Behavioral, Teamwork & "Why REI?"

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 time you had to learn a new technology quickly to deliver a project.

Medium · Behavioral, Teamwork & "Why REI?"

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 approach mentoring junior engineers or collaborating with non-technical stakeholders?

Medium · Behavioral, Teamwork & "Why REI?"

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?