A Software Engineer at Esper plays a pivotal role in developing and maintaining innovative software solutions that empower businesses to manage and optimize their device fleets. This position is critical as it directly impacts the user experience and operational efficiency of our clients, driving the overall success of our products. You will work on complex problems, such as creating scalable applications that cater to various customer needs, ensuring that our solutions remain at the forefront of technology. In this role, you will collaborate with cross-functional teams to design, implement, and enhance systems that support the company's strategic goals. You'll have the opportunity to work on exciting projects involving cloud services, device management, and automation, which are essential for future-proofing our offerings. Being part of the Esper engineering team means contributing to groundbreaking solutions that shape how businesses interact with technology on a daily basis.
HR Screening
reportedInitial screening conducted by HR to assess candidate's background and fit for the role.
What to demonstrate
- Initial screening conducted by HR to assess candidate's background and fit for the role
- Depth in Data Structures & Algorithms (DSA)
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 Assessments
reportedIn-depth technical interviews with engineering team members to evaluate coding skills.
What to demonstrate
- In-depth technical interviews with engineering team members to evaluate coding skills
- Depth in Data Structures & Algorithms (DSA)
How to prepare
- Answer aloud and timed: Describe a challenging coding project you worked on and the outcome.
- Answer aloud and timed: What design patterns do you frequently use, and why?
Behavioral Interviews
reportedInterviews focused on assessing cultural fit and problem-solving approaches.
What to demonstrate
- Interviews focused on assessing cultural fit and problem-solving approaches
- Depth in Data Structures & Algorithms (DSA)
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral interviews above and write down what you would ask to confirm before it.
PracHub editorial advice for the preparation topics above.
Understand the company's mission
Familiarize yourself with Esper's vision and how your role contributes to achieving it.
Prepare for coding interviews
Practice coding problems on platforms like LeetCode or HackerRank to sharpen your skills and increase your confidence.
Showcase your projects
Be ready to discuss past projects in detail, focusing on your contributions and the impact on the team and organization.
Be authentic
Approach behavioral questions with genuine examples that reflect your values and working style.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a function to reverse a linked list.
Write a function to reverse a linked list.
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 how you would find the longest substring without repeating characters.
Explain how you would find the longest substring without repeating characters.
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?
Given an array of integers, find two numbers such that they add up to a specific target.
Given an array of integers, find two numbers such that they add up to a specific target.
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?
Discuss the time complexity of your solution for a given problem.
Discuss the time complexity of your solution for a given problem.
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?
Write a function to perform binary search on a sorted array.
Write a function to perform binary search on a sorted array.
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?
Stop tag and share joins from fanning out a page
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
- 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.
- 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.
- 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.
- 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?
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?
Explain the difference between REST and GraphQL.
Explain the difference between REST and GraphQL.
Approach
- Say who the caller is and what they do when the call fails halfway.
- Define the identity of a request so a retry cannot double-apply it.
- Separate accepted, pending, failed and confirmed; they are different facts.
- 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?
Describe a challenging coding project you worked on and the outcome.
Describe a challenging coding project you worked on and the outcome.
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?
What design patterns do you frequently use, and why?
What design patterns do you frequently use, and why?
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?
How do you ensure code quality and maintainability?
How do you ensure code quality and maintainability?
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?
Design a system for real-time data processing. What considerations would you take into account?
Design a system for real-time data processing. What considerations would you take into account?
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?
How would you handle scaling a web application to support millions of users?
How would you handle scaling a web application to support millions of users?
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?
Describe the architecture of a project you have previously worked on.
Describe the architecture of a project you have previously worked on.
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?
What strategies do you implement to ensure system reliability and performance?
What strategies do you implement to ensure system reliability and performance?
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?
How would you design a RESTful API for a mobile application?
How would you design a RESTful API for a mobile application?
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?
Given a scenario where your application is experiencing latency issues, how would you diagnose and address the
Given a scenario where your application is experiencing latency issues, how would you diagnose and address the problem?
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?
How would you approach a situation where you need to implement a feature but face significant technical challe
How would you approach a situation where you need to implement a feature but face significant technical challenges?
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?
Analyze a recent technology trend and discuss its potential impact on software development.
Analyze a recent technology trend and discuss its potential impact on software development.
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?
How do you approach debugging a complex issue in your code?
How do you approach debugging a complex issue in your code?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- 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?
Built from the rounds and topics Esper candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Esper loop
- Write out the reported sequence: HR Screening, Technical Assessments, Behavioral 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 3 reported rounds, with the weakest marked.
02Work Data Structures & Algorithms (DSA)
- Spend the session on Data Structures & Algorithms (DSA), which Esper candidates report being tested on.
- Write one worked example in Data Structures & Algorithms (DSA) and time yourself on it.
Deliverable: One timed worked example in Data Structures & Algorithms (DSA).
03Work Coding Interviews
- Spend the session on Coding Interviews, which Esper candidates report being tested on.
- Write one worked example in Coding Interviews and time yourself on it.
Deliverable: One timed worked example in Coding Interviews.
04Work System Design
- Spend the session on System Design, which Esper candidates report being tested on.
- Write one worked example in System Design and time yourself on it.
Deliverable: One timed worked example in System Design.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the difference between REST and GraphQL.
- Answer aloud, timed: How do you approach debugging a complex issue in your code?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: System Design / Architecture
- Answer aloud, timed: Design a system for real-time data processing. What considerations would you take into account?
- Answer aloud, timed: How would you handle scaling a web application to support millions of users?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Tell me about a time when you had to resolve a conflict within your team.
- Answer aloud, timed: How do you prioritize tasks when faced with multiple deadlines?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership 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.
Tell me about a time when you had to resolve a conflict within your team.
Tell me about a time when you had to resolve a conflict within your team.
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?
How do you prioritize tasks when faced with multiple deadlines?
How do you prioritize tasks when faced with multiple deadlines?
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 situation where you took the initiative to improve a process.
Describe a situation where you took the initiative to improve a process.
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?
How do you handle feedback and criticism of your work?
How do you handle feedback and criticism of your work?
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?
What motivates you to contribute to a team's success?
What motivates you to contribute to a team's success?
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
Tell me about a time when you had to resolve a conflict within your team.
- 02
How do you prioritize tasks when faced with multiple deadlines?
- 03
Describe a situation where you took the initiative to improve a process.
- 04
How do you handle feedback and criticism of your work?
How difficult is the interview process, and how much preparation time is typical?
The interview process is considered challenging but fair. Candidates typically spend several weeks preparing, focusing on both technical skills and behavioral questions to align with Esper's values.
Esper Software Engineer candidate reports ↗What differentiates successful candidates from others?
Successful candidates demonstrate a combination of strong technical skills, effective problem-solving abilities, and a clear alignment with Esper's culture of collaboration and innovation.
Esper Software Engineer candidate reports ↗What is the working style and culture like at Esper?
Esper fosters a collaborative and inclusive environment where teamwork and open communication are encouraged. Employees are expected to take initiative and contribute to the continuous improvement of processes and products.
Esper Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The timeline can vary, but candidates often complete the interview process within a few weeks, depending on scheduling and team availability.
Esper Software Engineer candidate reports ↗Are there remote work options available?
Esper supports flexible working arrangements, including remote work, to accommodate diverse working styles and preferences.
Esper Software Engineer candidate reports ↗How many rounds does Esper have for a Software Engineer interview, and what are the stages?
The Esper Software Engineer process includes HR screening first, then technical assessments, and behavioral interviews. The guide also notes that candidates often move through multiple rounds at a fast pace, and interviews are primarily conducted online. Technical assessments focus on coding skills with engineering team members.
Esper Software Engineer candidate reports ↗How hard is the Esper Software Engineer interview, based on candidate reports?
Candidate-reported difficulty for Esper Software Engineer interviews is mostly average.
Esper Software Engineer candidate reports ↗What topics does Esper test for Software Engineer candidates?
Coding and problem solving are central, with Data Structures and Algorithms (DSA) and coding interviews explicitly listed. System design and architecture show up through system design, architecture questions, scalability, and distributed systems concepts. The guide also calls out learning agility as a topic area.
Esper Software Engineer candidate reports ↗What kind of coding questions and problem-solving prompts does Esper use?
Public sample questions include “Two Sum for Target” and “Improving Measurement Without Being Asked.” The guide content also indicates you should expect algorithmic coding tasks and questions that test time complexity and algorithmic thinking. In problem-solving, you may also be asked how you would diagnose latency issues in an application.
Esper Software Engineer candidate reports ↗What system design and architecture questions should I prepare for at Esper as a Software Engineer?
Expect system design and architecture prompts that cover real-time data processing considerations, scaling a web application to support millions of users, and designing a RESTful API for a mobile application. Reliability and performance strategies are also mentioned as themes. Distributed systems concepts and scalability are listed among the top topics.
Esper Software Engineer candidate reports ↗What salary does Esper offer for a Software Engineer, and does pay vary?
No compensation numbers are provided in the supplied Esper Software Engineer guide or structured data. If you have a job posting link or level, share it and I can help you interpret it using only your provided text.
Esper 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.
- 01Esper 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
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