As a Software Engineer at Ontra, you will play a pivotal role in shaping the technology that powers our innovative legal operations platform. This role is essential for developing scalable software solutions that enhance efficiency and accuracy in legal document management. The impact of your work will be felt across various teams, enabling them to serve clients more effectively and contributing to the overall success of the business. In this position, you will collaborate closely with product managers, designers, and other engineers to solve complex problems and deliver high-quality code. You will be at the forefront of building features that directly affect user experience and operational workflows, making your contributions critical to both user satisfaction and business goals. Expect to engage with cutting-edge technologies and work on impactful projects that challenge your skills and expand your expertise.
Phone Screen
reportedInitial call with a recruiter to discuss your background and the role in detail.
What to demonstrate
- Initial call with a recruiter to discuss your background and the role in detail
- Depth in Technical Coding Interviews
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.
Interviews with Hiring Manager
reportedMeetings with the hiring manager to assess your fit for the role.
What to demonstrate
- Meetings with the hiring manager to assess your fit for the role
- Depth in Technical Coding Interviews
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.
Technical Assessments
reportedEvaluation of your technical skills through various assessments.
What to demonstrate
- Evaluation of your technical skills through various assessments
- Depth in Technical Coding Interviews
How to prepare
- Answer aloud and timed: What tools and practices do you use for version control?
- Answer aloud and timed: Design a URL shortening service. What components would you include?
Team Discussions
reportedConversations with team members to evaluate cultural fit and collaboration.
What to demonstrate
- Conversations with team members to evaluate cultural fit and collaboration
- Depth in Technical Coding Interviews
How to prepare
- Answer aloud and timed: How would you approach scaling an application for increased user demand?
- Answer aloud and timed: Describe how you would implement a caching mechanism. What strategies would you use?
PracHub editorial advice for the preparation topics above.
Prepare for Conversational Interviews
The interview process at Ontra tends to be more conversational, so practice articulating your thoughts clearly and engagingly.
Showcase Collaboration Skills
Be ready to discuss how you have successfully collaborated with cross-functional teams in the past.
Research the Company Culture
Understanding Ontra’s mission and values will help you articulate your fit within the organization.
Ask Insightful Questions
Prepare thoughtful questions to ask your interviewers, demonstrating your interest in the role and the company.
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?
Implement a search algorithm for a sorted array.
Implement a search algorithm for 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?
How would you find the longest substring without repeating characters in a string?
How would you find the longest substring without repeating characters in a string?
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?
Describe the time complexity of your solution and any optimizations you could implement.
Describe the time complexity of your solution and any optimizations you could implement.
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 a list of integers, write a program to find all unique triplets that sum to zero.
Given a list of integers, write a program to find all unique triplets that sum to zero.
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?
What factors do you consider when designing a database schema?
What factors do you consider when designing a database schema?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- 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?
Write the update path that detects a concurrent edit
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
- 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.
- 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.
- 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.
- 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 programming languages are you most proficient in, and why?
What programming languages are you most proficient in, 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?
Describe a challenging technical problem you solved. What was your approach?
Describe a challenging technical problem you solved. What was your approach?
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 the quality of your code?
How do you ensure the quality of your code?
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?
Explain the concept of RESTful APIs and their importance in web development.
Explain the concept of RESTful APIs and their importance in web 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?
What tools and practices do you use for version control?
What tools and practices do you use for version control?
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 URL shortening service. What components would you include?
Design a URL shortening service. What components would you include?
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 approach scaling an application for increased user demand?
How would you approach scaling an application for increased user demand?
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 how you would implement a caching mechanism. What strategies would you use?
Describe how you would implement a caching mechanism. What strategies would you use?
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?
Explain the trade-offs between microservices and monolithic architecture.
Explain the trade-offs between microservices and monolithic architecture.
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 set of user requirements, how would you prioritize features for a product?
Given a set of user requirements, how would you prioritize features for a product?
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?
Describe how you would handle a situation where project requirements change unexpectedly.
Describe how you would handle a situation where project requirements change unexpectedly.
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 steps do you take when faced with a tight deadline?
What steps do you take when faced with a tight deadline?
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 learning a new technology or programming language?
How do you approach learning a new technology or programming language?
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 debugging a complex issue in a production environment?
How would you approach debugging a complex issue in a production environment?
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 Ontra candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Ontra loop
- Write out the reported sequence: Phone Screen, Interviews with Hiring Manager, Technical Assessments, Team 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 4 reported rounds, with the weakest marked.
02Work Technical Coding Interviews
- Spend the session on Technical Coding Interviews, which Ontra candidates report being tested on.
- Write one worked example in Technical Coding Interviews and time yourself on it.
Deliverable: One timed worked example in Technical Coding Interviews.
03Work System Design
- Spend the session on System Design, which Ontra 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.
04Work Data Schema Design
- Spend the session on Data Schema Design, which Ontra candidates report being tested on.
- Write one worked example in Data Schema Design and time yourself on it.
Deliverable: One timed worked example in Data Schema Design.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What programming languages are you most proficient in, and why?
- Answer aloud, timed: Describe a challenging technical problem you solved. What was your approach?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: System Design / Architecture
- Answer aloud, timed: Design a URL shortening service. What components would you include?
- Answer aloud, timed: How would you approach scaling an application for increased user demand?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time when you led a project or initiative. What challenges did you face?
- Answer aloud, timed: How do you handle conflict within a team?
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.
Describe a time when you led a project or initiative. What challenges did you face?
Describe a time when you led a project or initiative. What challenges did you face?
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 conflict within a team?
How do you handle conflict within a 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?
Can you give an example of how you mentored a junior engineer?
Can you give an example of how you mentored a junior engineer?
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 values are most important to you in a work environment?
What values are most important to you in a work environment?
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 time when you had to make a difficult decision. What was the outcome?
Describe a time when you had to make a difficult decision. What was the outcome?
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
Describe a time when you led a project or initiative. What challenges did you face?
- 02
How do you handle conflict within a team?
- 03
Can you give an example of how you mentored a junior engineer?
- 04
What values are most important to you in a work environment?
How difficult are the interviews at Ontra?
The interviews can vary in difficulty, but candidates should expect a mix of technical and behavioral questions that test both knowledge and cultural fit.
Ontra Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates typically demonstrate a strong understanding of technical concepts, a collaborative mindset, and alignment with Ontra's core values.
Ontra Software Engineer candidate reports ↗What is the typical timeline from the initial screen to an offer?
The interview process generally takes 2-3 weeks, depending on scheduling and the number of interview rounds.
Ontra Software Engineer candidate reports ↗How does the company support remote work or hybrid expectations?
Ontra supports flexible work arrangements, allowing for a blend of remote and in-office work depending on team needs and individual preferences.
Ontra Software Engineer candidate reports ↗What topics does Ontra test in interviews?
Ontra interviews most often cover Stakeholder Communication, Presentation Skills, Problem Solving, Time Management, and Interview Process Design. The exact emphasis depends on the specific role you apply for.
Ontra 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.
- 01Ontra 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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