CHEP Software Engineer Interview Guide

The 60-second brief

As a Software Engineer at CHEP, you are at the heart of the world’s largest circular economy. CHEP is the global leader in managed pooling solutions, and our software engineers are responsible for the digital backbone that tracks and manages millions of supply chain assets—pallets, crates, and containers—across 60 countries. Your work directly impacts the efficiency of global commerce and the sustainability of the planet by optimizing how goods move from producers to consumers. The engineering team at CHEP solves complex logistical challenges using a modern tech stack, including React, TypeScript, and JavaScript. You will work on high-scale platforms that handle massive amounts of data, integrate with IoT tracking devices, and provide real-time visibility into global supply chains.

This guide is scoped to a Software Engineer candidate at CHEP.

Focus areas

• Coding (general)
• React
• Practical coding / hands-on coding

The CHEP interview process

CHEP candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Recruiter Screening Call

Initial call to discuss your background and interest in the Software Engineer role.

What to demonstrate

• Initial call to discuss your background and interest in the Software Engineer role
• Depth in Coding (general)

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.

Technical Assessment

Timed assessment focusing on fundamentals like React and TypeScript.

What to demonstrate

• Timed assessment focusing on fundamentals like React and TypeScript
• Depth in Coding (general)

How to prepare

• Answer aloud and timed: Describe the "Temporal Dead Zone" in JavaScript.
• Answer aloud and timed: How would you handle state management across a large-scale application with multiple nested components?

Live Coding Session

Interactive coding session with a hiring manager and senior engineers.

What to demonstrate

• Interactive coding session with a hiring manager and senior engineers
• Depth in Coding (general)

How to prepare

• Answer aloud and timed: What are the pros and cons of using Functional Components vs. Class Components in modern React?
• Answer aloud and timed: Write a function to flatten a deeply nested array without using built-in methods.

Project Presentation

Present a technical project or previous work to a panel of managers.

What to demonstrate

• Present a technical project or previous work to a panel of managers
• Depth in Coding (general)

How to prepare

• Answer aloud and timed: How would you implement a "loading" state for multiple concurrent API calls?
• Answer aloud and timed: Given a string, find the first non-repeating character.

Where candidates lose points

Master the MCQ

For the 30-question assessment, you have roughly one minute per question. Practice your JavaScript and React fundamentals until they are second nature to ensure you don't run out of time.

Video Policy Awareness

Be aware that CHEP often requires candidates to have their video on during interviews, even if the interviewer does not. Prepare your environment accordingly to remain professional.

Showcase In-house Adaptability

Mentioning your experience with proprietary frameworks or your ability to quickly ramp up on custom internal tools will resonate well with CHEP's engineering culture.

Explain the "Why

During live coding, talk through your thought process. Even if you don't finish a task, showing a logical and structured approach can still lead to a positive evaluation.

Questions & practice

Write a function to flatten a deeply nested array without using built-in methods.

Medium · Coding & Logic

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?

Given a string, find the first non-repeating character.

Medium · Coding & Logic

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 how you would implement a custom hook for handling window resizing.

Medium · Coding & Logic

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?

Solve a series of multiple-choice questions on JavaScript closures and hoisting.

Medium · Coding & Logic

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?

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?

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?

What are the primary differences between an Interface and a Type in TypeScript?

Medium · Frontend & Core Web Technologies

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 does the React Virtual DOM improve performance?

Medium · Frontend & Core Web Technologies

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?

Describe the "Temporal Dead Zone" in JavaScript.

Medium · Frontend & Core Web Technologies

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 would you handle state management across a large-scale application with multiple nested components?

Medium · Frontend & Core Web Technologies

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?

What are the pros and cons of using Functional Components vs. Class Components in modern React?

Medium · Frontend & Core Web Technologies

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 would you implement a "loading" state for multiple concurrent API calls?

Medium · Coding & Logic

Approach

1. Say who the caller is and what they do when the call fails halfway.
2. Define the identity of a request so a retry cannot double-apply it.
3. Separate accepted, pending, failed and confirmed; they are different facts.
4. 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?

What is your process for debugging a complex production issue?

Medium · Behavioral & Experience

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 CHEP candidates report.

Day 1 — Map the CHEP loop

• Write out the reported sequence: Recruiter Screening Call, Technical Assessment, Live Coding Session, Project Presentation.
• 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 Coding (general)

• Spend the session on Coding (general), which CHEP candidates report being tested on.
• Write one worked example in Coding (general) and time yourself on it.

Deliverable: One timed worked example in Coding (general).

Day 3 — Work React

• Spend the session on React, which CHEP candidates report being tested on.
• Write one worked example in React and time yourself on it.

Deliverable: One timed worked example in React.

Day 4 — Work Practical coding / hands-on coding

• Spend the session on Practical coding / hands-on coding, which CHEP candidates report being tested on.
• Write one worked example in Practical coding / hands-on coding and time yourself on it.

Deliverable: One timed worked example in Practical coding / hands-on coding.

Day 5 — Answer out loud: Frontend & Core Web Technologies

• Answer aloud, timed: What are the primary differences between an Interface and a Type in TypeScript?
• Answer aloud, timed: How does the React Virtual DOM improve performance?

Deliverable: Spoken answers to 2 reported Frontend & Core Web Technologies question(s), under time.

Day 6 — Answer out loud: Coding & Logic

• Answer aloud, timed: Write a function to flatten a deeply nested array without using built-in methods.
• Answer aloud, timed: How would you implement a "loading" state for multiple concurrent API calls?

Deliverable: Spoken answers to 2 reported Coding & Logic question(s), under time.

Day 7 — Answer out loud: Behavioral & Experience

• Answer aloud, timed: Tell me about a time you had to work with a difficult stakeholder or team member.
• Answer aloud, timed: Describe a project where you had to learn a new technology very quickly.

Deliverable: Spoken answers to 2 reported Behavioral & Experience question(s), under time.

Behavioural preparation

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

Tell me about a time you had to work with a difficult stakeholder or team member.

Medium · Behavioral & Experience

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 project where you had to learn a new technology very quickly.

Medium · Behavioral & Experience

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 ensure your code is accessible to all users?

Medium · Behavioral & Experience

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 at CHEP specifically, and how does your experience align with our mission?

Medium · Behavioral & Experience

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?