A Software Engineer at National Oilwell Varco (NOV) plays a critical role in bridging the gap between heavy industrial machinery and cutting-edge digital intelligence. As a global leader in oilfield equipment, rig technologies, and industrial operations, National Oilwell Varco relies on its software engineering teams to build, deploy, and maintain the complex control systems, data pipelines, and enterprise applications that power global energy infrastructure. Whether you are developing real-time control systems for multi-million dollar drilling rigs or writing data analytics tools to optimize asset performance, your work directly impacts the safety, efficiency, and sustainability of global operations. Unlike traditional technology firms where software exists purely in the cloud, software engineering at National Oilwell Varco is deeply tangible. You will work on software that interacts directly with physical hardware, sensors, and mechanical systems. This requires a unique blend of robust system architecture design, real-time performance optimization, and a deep appreciation for the physical environments in which your software will operate. Your code will run on offshore platforms, remote land rigs, and manufacturing facilities worldwide, making reliability, security, and safety-critical design paramount. This position is highly collaborative, offering the chance to work alongside mechanical engineers, electrical engineers, and product managers.
Initial Screening
reportedA brief phone call with HR or a hiring manager to review your background and discuss career goals.
What to demonstrate
- A brief phone call with HR or a hiring manager to review your background and discuss career goals
- Depth in Behavioral interview skills
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 Evaluation
reportedInvolves a coding challenge, take-home test, or technical phone interview focusing on OOP, SQL, and system design.
What to demonstrate
- Involves a coding challenge, take-home test, or technical phone interview focusing on OOP, SQL, and system design
- Depth in Behavioral interview skills
How to prepare
- Answer aloud and timed: Explain how you would implement a standard search algorithm and optimize its time complexity.
- Answer aloud and timed: Walk through a basic string manipulation problem and discuss how you handle edge cases such as null inputs or special characters.
Onsite / Panel Interview
reportedA multi-hour round including behavioral discussions, whiteboard problem-solving, and a panel interview with engineering leads.
What to demonstrate
- A multi-hour round including behavioral discussions, whiteboard problem-solving, and a panel interview with engineering leads
- Depth in Behavioral interview skills
How to prepare
- Answer aloud and timed: Explain the core pillars of Object-Oriented Programming (OOP) and give a real-world example of how you have applied inheritance and polymorphism in a project.
- Answer aloud and timed: What is the difference between a Web Service and Windows Communication Foundation (WCF)? When would you choose one over the other?
Facility Tour & Wrap-up
reportedConcludes the onsite interview with a tour of the local manufacturing plant or engineering facility.
What to demonstrate
- Concludes the onsite interview with a tour of the local manufacturing plant or engineering facility
- Depth in Behavioral interview skills
How to prepare
- Answer aloud and timed: Describe the Software Development Life Cycle (SDLC) phases and explain your preferred methodology when managing a fast-paced project.
- Answer aloud and timed: How would you design a software architecture to handle real-time data streaming from multiple hardware sensors on a drilling rig?
1 candidate reports. Individual accounts describe a particular role and hiring cycle.
National Oilwell Varco Software Engineer interview: calm whiteboard screen
A recruiter conversation set expectations and made the process feel systematic. I received detailed information in advance and the interviews did not feel pressurized. The overall timeline seemed likely to run about one or two months. An early Zoom screen covered basics and me as a person: school or curriculum background, research interests, extracurriculars, and personality-style questions. A la…
Read full experiencePracHub editorial advice for the preparation topics above.
Highlight Practical Projects
When discussing your portfolio, focus on projects where you had to solve real-world problems, optimize performance, or integrate with hardware or external APIs.
Show Enthusiasm for the Industry
Take the time to research NOV's recent innovations and product lines. Showing that you understand the scale and importance of their industrial machinery will make a highly positive impression on the hiring managers.
Brush Up on Databases
Do not skip your SQL preparation. Be ready to write queries on a whiteboard, explain optimization strategies, and discuss data normalization.
Be Honest About Your Skills
If you do not know the answer to a technical question, walk the interviewer through your thought process on how you would find the answer. NOV managers value honesty, logical thinking, and coachability over memorized answers.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a program that takes a list of numbers as input and outputs the missing numbers in the sequence (e.g., I
Write a program that takes a list of numbers as input and outputs the missing numbers in the sequence (e.g., Input: [1, 2, 5, 7, 9], Output: [3, 4, 6, 8]).
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?
Analyze a provided code snippet and determine the final value of a specific variable after execution.
Analyze a provided code snippet and determine the final value of a specific variable after execution.
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 implement a standard search algorithm and optimize its time complexity.
Explain how you would implement a standard search algorithm and optimize its time complexity.
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?
Walk through a basic string manipulation problem and discuss how you handle edge cases such as null inputs or
Walk through a basic string manipulation problem and discuss how you handle edge cases such as null inputs or special 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?
Write a SQL Union Query to combine data from three tables sharing the same unique ID.
Write a SQL Union Query to combine data from three tables sharing the same unique ID.
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?
What is the difference between `DROP`, `DELETE`, and `TRUNCATE` tables in SQL? Explain the performance and tra
What is the difference between DROP, DELETE, and TRUNCATE tables in SQL? Explain the performance and transactional implications of each.
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?
How do you design database schemas to ensure data integrity when dealing with relational databases?
How do you design database schemas to ensure data integrity when dealing with relational databases?
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?
Explain the core pillars of Object-Oriented Programming (OOP) and give a real-world example of how you have ap
Explain the core pillars of Object-Oriented Programming (OOP) and give a real-world example of how you have applied inheritance and polymorphism in a project.
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 is the difference between a Web Service and Windows Communication Foundation (WCF)? When would you choose
What is the difference between a Web Service and Windows Communication Foundation (WCF)? When would you choose one over the other?
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 Software Development Life Cycle (SDLC) phases and explain your preferred methodology when managin
Describe the Software Development Life Cycle (SDLC) phases and explain your preferred methodology when managing a fast-paced project.
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 software architecture to handle real-time data streaming from multiple hardware sensors
How would you design a software architecture to handle real-time data streaming from multiple hardware sensors on a drilling rig?
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 write and optimize a stored procedure to handle high-frequency data insertion.
Describe how you would write and optimize a stored procedure to handle high-frequency data insertion.
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 a basic electrical circuit concept, including how you calculate voltage, current, resistance, and powe
Explain a basic electrical circuit concept, including how you calculate voltage, current, resistance, and power.
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?
How would you approach writing software that must interface with a proprietary hardware tool or sensor?
How would you approach writing software that must interface with a proprietary hardware tool or sensor?
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?
Listing latency scales with page size, not with filters
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
- 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.
- 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.
- 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.
- 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?
Built from the rounds and topics National Oilwell Varco candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the National Oilwell Varco loop
- Write out the reported sequence: Initial Screening, Technical Evaluation, Onsite / Panel Interview, Facility Tour & Wrap-up.
- 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 Behavioral interview skills
- Spend the session on Behavioral interview skills, which National Oilwell Varco candidates report being tested on.
- Write one worked example in Behavioral interview skills and time yourself on it.
Deliverable: One timed worked example in Behavioral interview skills.
03Work Communication skills (technical + interview communication)
- Spend the session on Communication skills (technical + interview communication), which National Oilwell Varco candidates report being tested on.
- Write one worked example in Communication skills (technical + interview communication) and time yourself on it.
Deliverable: One timed worked example in Communication skills (technical + interview communication).
04Work Project experience storytelling
- Spend the session on Project experience storytelling, which National Oilwell Varco candidates report being tested on.
- Write one worked example in Project experience storytelling and time yourself on it.
Deliverable: One timed worked example in Project experience storytelling.
05Answer out loud: Coding & Algorithms
- Answer aloud, timed: Write a program that takes a list of numbers as input and outputs the missing numbers in the sequence (e.g., Input: `[1, 2, 5, 7, 9]`, Output: `[3, 4, 6, 8]`).
- Answer aloud, timed: Analyze a provided code snippet and determine the final value of a specific variable after execution.
Deliverable: Spoken answers to 2 reported Coding & Algorithms question(s), under time.
06Answer out loud: System Design & Object-Oriented Programming (OOP)
- Answer aloud, timed: Explain the core pillars of Object-Oriented Programming (OOP) and give a real-world example of how you have applied inheritance and polymorphism in a project.
- Answer aloud, timed: What is the difference between a Web Service and Windows Communication Foundation (WCF)? When would you choose one over the other?
Deliverable: Spoken answers to 2 reported System Design & Object-Oriented Programming (OOP) question(s), under time.
07Answer out loud: Database & SQL
- Answer aloud, timed: Write a SQL Union Query to combine data from three tables sharing the same unique ID.
- Answer aloud, timed: What is the difference between `DROP`, `DELETE`, and `TRUNCATE` tables in SQL? Explain the performance and transactional implications of each.
Deliverable: Spoken answers to 2 reported Database & SQL 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 you had to learn a completely new programming language or technology on a very tight dead
Tell me about a time you had to learn a completely new programming language or technology on a very tight deadline. How did you approach it?
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 had to work with a difficult team member or stakeholder. How did you resolve th
Describe a situation where you had to work with a difficult team member or stakeholder. How did you resolve the conflict to deliver the project?
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?
Why do you want to work for National Oilwell Varco, and what do you know about our role in the global energy i
Why do you want to work for National Oilwell Varco, and what do you know about our role in the global energy industry?
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 situations where technical requirements are ambiguous or change mid-project?
How do you handle situations where technical requirements are ambiguous or change mid-project?
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 your experience, if any, with mechanical fundamentals or control systems (such as PLCs or SCADA syste
Describe your experience, if any, with mechanical fundamentals or control systems (such as PLCs or SCADA systems).
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 you had to learn a completely new programming language or technology on a very tight deadline. How did you approach it?
- 02
Describe a situation where you had to work with a difficult team member or stakeholder. How did you resolve the conflict to deliver the project?
- 03
Why do you want to work for National Oilwell Varco, and what do you know about our role in the global energy industry?
- 04
How do you handle situations where technical requirements are ambiguous or change mid-project?
How technical are the software engineering interviews at NOV?
The interviews are highly practical rather than hyper-academic. You should expect questions focused on your direct experience, OOP design, SQL, and basic algorithm design. You are much more likely to be asked to solve a practical coding problem or database query than an abstract, highly complex algorithmic puzzle.
National Oilwell Varco Software Engineer candidate reports ↗Do I need prior experience in the oil and gas industry to apply?
No. While industry experience is a plus, NOV highly values strong software engineering fundamentals and a willingness to learn. Many successful software engineers join NOV from entirely different industries, bringing fresh perspectives on modern software practices.
National Oilwell Varco Software Engineer candidate reports ↗What is the company culture like for software engineers?
The culture is generally described as down-to-earth, collaborative, and highly professional. Because software engineers work closely with hardware and mechanical teams, the environment is very practical and results-oriented. It lacks the hyper-competitive atmosphere of some pure tech companies, focusing instead on teamwork and reliable execution.
National Oilwell Varco Software Engineer candidate reports ↗Is travel required for this role?
This depends heavily on the specific team. Some roles, particularly in control systems or field applications, may require occasional travel to manufacturing facilities, test sites, or active rigs (onshore or offshore). Other enterprise software roles are entirely office-based. This will typically be clarified early in the interview process.
National Oilwell Varco Software Engineer candidate reports ↗What topics does National Oilwell Varco test in interviews?
National Oilwell Varco interviews most often cover Problem Solving, Incoterms, Behavioral Interviewing, Stakeholder Management, and Stakeholder Interaction. The exact emphasis depends on the specific role you apply for.
National Oilwell Varco 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.
- 01National Oilwell Varco 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
Explore related engineering environments and compare the preparation focus.
Cognition Software Engineer Interview Guide
What Cognition asks Software Engineer candidates, from reported rounds and questions.
Discord Software Engineer Interview Guide
Database practice for Discord candidates: how an index changes a query plan, and which anomalies survive a given isolation level, since read committed still permits non-repeatable reads.
CoreWeave Software Engineer Interview Guide
Failure-handling practice for CoreWeave software engineer candidates: requests whose outcome a timeout leaves unknown, where a retry is safe, and deduplicating at the receiver instead of assuming exactly-once delivery.
Aerospike Software Engineer Interview Questions & Guide 2026
Aerospike database-engine preparation through an original single-owner Python key-value store with bounded logical index accounting, disk-offset reads, conditional writes, tombstones, process-restart recovery and 3,240 checks. Existing 14 p