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Course Hero Software Engineer Interview Guide

Course Hero Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

As a Software Engineer at Course Hero, you are at the heart of an educational mission to empower students to learn more effectively. You will be responsible for building, scaling, and maintaining the platform that connects millions of students with study resources, experts, and collaborative tools. Your work directly impacts how students navigate their academic journeys, requiring a balance of technical rigor and a passion for educational equity. This role is critical to the Course Hero product ecosystem. You will work on high-traffic systems that demand both stability and rapid iteration. Whether you are optimizing database queries, building responsive front-end components, or designing scalable back-end services, you are expected to treat the platform as a living product that evolves with the needs of our global user base.

This guide is scoped to a Software Engineer candidate at Course Hero.

Focus areas

  • Data Structures & Algorithms
  • Runtime Analysis / Time Complexity
  • Problem Solving (Coding Challenges)

The Course Hero interview process

Course Hero candidates report 2 rounds over 2-4 weeks. The stages below are what candidates describe, not a published process.

Initial Assessment

Assessment of technical fundamentals to gauge candidate's baseline skills.

What to demonstrate

  • Assessment of technical fundamentals to gauge candidate's baseline skills
  • Depth in Data Structures & Algorithms

How to prepare

  • Answer aloud and timed: Explain the time complexity of your solution and how it could be optimized.
  • Answer aloud and timed: How would you handle a scenario requiring string manipulation or complex data parsing?

Deep-Dive Discussions

In-depth discussions with the teams you would be working with daily.

What to demonstrate

  • In-depth discussions with the teams you would be working with daily
  • Depth in Data Structures & Algorithms

How to prepare

  • Answer aloud and timed: Given two tables, write a query using JOIN and aggregation functions to extract specific data.
  • Answer aloud and timed: Solve a coding challenge involving an array or linked list (e.g., reversing a structure or finding a specific element).

Where candidates lose points

Practice Collaborative Coding

Use tools that allow for real-time code sharing. Practice explaining your logic out loud as you write, as this is a key part of our technical evaluation.

Research the Product

Understand what Course Hero does. Having a clear idea of our users and the challenges they face will help you provide more meaningful answers during behavioral rounds.

Be Prepared to Discuss Your Past Work

Have a few specific examples of projects you've worked on, the challenges you faced, and the impact you had. Use the STAR method (Situation, Task, Action, Result) to keep your stories focused.

Ask Insightful Questions

We look for curiosity. Prepare questions about our tech stack, our engineering culture, or how we tackle specific scaling challenges.

Questions & practice

Explain the time complexity of your solution and how it could be optimized.

Medium · Technical & Algorithmic Foundations

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?

How would you handle a scenario requiring string manipulation or complex data parsing?

Medium · Technical & Algorithmic Foundations

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 coding challenge involving an array or linked list (e.g., reversing a structure or finding a specific

Medium · Technical & Algorithmic Foundations

Solve a coding challenge involving an array or linked list (e.g., reversing a structure or finding a specific element).

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 two tables, write a query using JOIN and aggregation functions to extract specific data.

Medium · Technical & Algorithmic Foundations

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?

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 design a system to handle high volumes of document uploads and retrieval?

Medium · System Design & Architecture

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?

What are the trade-offs between different database designs for our specific use cases?

Medium · System Design & Architecture

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?

How do you approach web security when building user-facing features?

Medium · System Design & Architecture

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?

Explain how you would optimize the front-end performance of a content-heavy page.

Medium · System Design & Architecture

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?

Exports duplicate a row range about once a week

Hard · leases · clock skew · idempotency

Roughly once a week an export writes a file containing a duplicated range of rows. The affected job_run rows show attempt = 1, status = succeeded, one started_at, and a lease_owner naming a different host from the one whose logs show the job starting. Leases last 30 seconds and are heartbeated every 10 from inside the handler; lease_expires_at is computed on the worker and compared against the database's now(). Find the mechanism, and give a fix that holds even if you cannot fix the clocks.

Approach

  1. Start from the fact that eliminates the obvious answer. attempt = 1 means no retry was recorded, so this is not a re-run after failure; two workers ran the same row concurrently and the takeover path never touched the counter. lease_owner naming a host other than the one that started the job is the same statement from the other side.
  2. Enumerate the mechanisms that cause a premature takeover, then find the signal that separates them. Either the lease genuinely expired because the heartbeat did not fire, which is what happens when the heartbeat runs on the handler's own thread and the handler makes a long blocking call, or it only appeared expired because two clocks disagree, since lease_expires_at is written from the worker's clock and evaluated against the database's. The discriminator is the distribution: incidents clustered on the longest exports indict the heartbeat, incidents clustered on one host indict skew. Measure both, and measure each host's offset against the database directly.
  3. Read the reclaim query precisely. In PostgreSQL now() is transaction start time, not statement time, so a reclaimer holding a long transaction compares against an older timestamp than expected; clock_timestamp() is the statement-time function. This is worth ruling in or out before you redesign anything, because it changes which rows look expired.
  4. Remove the second clock rather than trying to synchronise it. Issue and extend the lease in the database, with lease_expires_at = now() + interval '30 seconds' in both the claim and the heartbeat, so exactly one clock is ever compared and worker skew stops mattering to this predicate.

Follow-up

  • The displaced worker has already streamed half the file to object storage. What makes that side effect safe to repeat?
  • You now count takeovers. What alert fires on that counter, and at what threshold?

Suggested practice checklist

Built from the rounds and topics Course Hero candidates report.

Day 1 — Map the Course Hero loop

  • Write out the reported sequence: Initial Assessment, Deep-Dive 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 2 reported rounds, with the weakest marked.

Day 2 — Work Data Structures & Algorithms

  • Spend the session on Data Structures & Algorithms, which Course Hero candidates report being tested on.
  • Write one worked example in Data Structures & Algorithms and time yourself on it.

Deliverable: One timed worked example in Data Structures & Algorithms.

Day 3 — Work Runtime Analysis / Time Complexity

  • Spend the session on Runtime Analysis / Time Complexity, which Course Hero candidates report being tested on.
  • Write one worked example in Runtime Analysis / Time Complexity and time yourself on it.

Deliverable: One timed worked example in Runtime Analysis / Time Complexity.

Day 4 — Work Problem Solving (Coding Challenges)

  • Spend the session on Problem Solving (Coding Challenges), which Course Hero candidates report being tested on.
  • Write one worked example in Problem Solving (Coding Challenges) and time yourself on it.

Deliverable: One timed worked example in Problem Solving (Coding Challenges).

Day 5 — Answer out loud: Technical & Algorithmic Foundations

  • Answer aloud, timed: Explain the time complexity of your solution and how it could be optimized.
  • Answer aloud, timed: How would you handle a scenario requiring string manipulation or complex data parsing?

Deliverable: Spoken answers to 2 reported Technical & Algorithmic Foundations question(s), under time.

Day 6 — Answer out loud: Behavioral & Cultural Alignment

  • Answer aloud, timed: Why do you want to work at Course Hero specifically?
  • Answer aloud, timed: Tell us about a time you faced a difficult technical challenge and how you resolved it.

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

Day 7 — Answer out loud: System Design & Architecture

  • Answer aloud, timed: How would you design a system to handle high volumes of document uploads and retrieval?
  • Answer aloud, timed: What are the trade-offs between different database designs for our specific use cases?

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

Behavioural preparation

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

How do you handle edge cases and boundary conditions in your code?

Medium · Technical & Algorithmic Foundations

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 Course Hero specifically?

Medium · Behavioral & Cultural Alignment

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 us about a time you faced a difficult technical challenge and how you resolved it.

Medium · Behavioral & Cultural Alignment

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 situation where you had to collaborate with a non-technical stakeholder.

Medium · Behavioral & Cultural Alignment

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 feedback or disagreements within a team?

Medium · Behavioral & Cultural Alignment

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 aspirations and how do they fit with our company culture?

Medium · Behavioral & Cultural Alignment

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?