A Software Engineer at TGS-NOPEC plays a pivotal role in developing cutting-edge software solutions that enhance the company's operational capabilities and drive innovation in the energy sector. You will be responsible for designing, coding, testing, and deploying software applications that contribute to the efficiency and effectiveness of TGS-NOPEC's services. This role is critical not only for maintaining the company’s competitive edge but also for ensuring that the software systems align with strategic business objectives. In your position, you will collaborate with multidisciplinary teams, including data scientists, geophysicists, and product managers, to create solutions that meet the diverse needs of clients in the oil and gas industry. You will have the opportunity to work on complex problems involving large datasets, and your contributions will directly impact the quality of services provided to users. Your work will not only enhance existing systems but also pave the way for future innovations that can transform how TGS-NOPEC leverages technology in its operations.
HR Screening
reportedInitial screening conducted by HR to assess candidate fit for the role.
What to demonstrate
- Initial screening conducted by HR to assess candidate fit for the role
- Depth in Programming Fundamentals
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 Interviews
reportedA series of interviews focusing on both behavioral and technical questions.
What to demonstrate
- A series of interviews focusing on both behavioral and technical questions
- Depth in Programming Fundamentals
How to prepare
- Answer aloud and timed: Describe a challenging bug you encountered and how you resolved it.
- Answer aloud and timed: How do you ensure code quality and maintainability in your projects?
Phone Interviews
reportedInitial technical discussions conducted over the phone.
What to demonstrate
- Initial technical discussions conducted over the phone
- Depth in Programming Fundamentals
How to prepare
- Answer aloud and timed: What experience do you have with version control systems like Git?
- Answer aloud and timed: Given a specific software problem, how would you approach finding a solution?
Web Conferencing
reportedTechnical interviews conducted via web conferencing tools.
What to demonstrate
- Technical interviews conducted via web conferencing tools
- Depth in Programming Fundamentals
How to prepare
- Answer aloud and timed: Describe a time when you had to make a trade-off between performance and maintainability.
- Answer aloud and timed: How would you handle conflicting requirements from different stakeholders?
In-Person Interviews
reportedFace-to-face interviews with team members to assess collaboration and fit.
What to demonstrate
- Face-to-face interviews with team members to assess collaboration and fit
- Depth in Programming Fundamentals
How to prepare
- Answer aloud and timed: Describe a situation where you worked in a team to achieve a common goal.
- Answer aloud and timed: How do you handle feedback and criticism from peers or supervisors?
PracHub editorial advice for the preparation topics above.
Understand the Industry
Familiarize yourself with the oil and gas sector, as this knowledge can enhance your relevance during interviews.
Practice Coding
Regularly solve coding challenges and participate in mock interviews to build confidence.
Showcase Projects
Be prepared to discuss your past projects in detail, highlighting your specific contributions and the impact of your work.
Be mindful of the interview environment
Past candidates have noted varying levels of respect during interviews, so approach each interaction professionally.
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 string.
Write a function to reverse 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?
How would you implement a sorting algorithm? Can you explain its time complexity?
How would you implement a sorting algorithm? Can you explain 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?
Given an array of integers, find two numbers that sum up to a specific target.
Given an array of integers, find two numbers that sum 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?
Keep soft-deleted accounts from blocking re-registration
app_user holds user_id, tenant_id, email CITEXT, password_hash (NULL for SSO principals), email_verified_at, auth_version, status ('invited','active','suspended','deactivated'), created_at, updated_at, deleted_at. Two live accounts for one address inside a tenant must be impossible, but an address freed by a soft delete must be reusable, and the same tenant may delete and re-register it repeatedly. Write the uniqueness DDL for PostgreSQL 16, then the equivalent for MySQL 8 where partial indexes do not exist, and say what each permits once three deleted rows already hold that address.
Approach
- Start from what is actually unique: not (tenant_id, email), but (tenant_id, email) among live rows. PostgreSQL says that directly — CREATE UNIQUE INDEX app_user_live_email ON app_user (tenant_id, email) WHERE deleted_at IS NULL. A full constraint over the same two columns burns the address permanently the first time someone deletes an account.
- Keep case-insensitivity in the type or the index, never in the application: CITEXT as given, or UNIQUE (tenant_id, lower(email)) as an expression index where the extension is unavailable. A case-sensitive unique column is exactly how two accounts for one human appear.
- For MySQL 8 the predicate has to move inside the key: add a discriminator column that is a constant 0 while the row is live and is set to user_id on delete, with UNIQUE (tenant_id, email, deleted_marker). Live rows share the constant and still collide; deleted rows differ from each other and stop colliding.
- State the NULL variant and its dependency: leaving the marker NULL for deleted rows also works, because a unique index treats NULLs as distinct — true in MySQL, and true in PostgreSQL only under the default NULLS DISTINCT, which PostgreSQL 15 lets you reverse. Check the polarity against the three existing deleted rows: constant-on-live is what preserves the collision you want, and reversing it silently admits duplicate live accounts.
Follow-up
- A deleted account re-registers with the same address the next day. Do the old resource rows follow the new user_id, and how does the API keep the two principals apart?
- How do you honour an erasure request while resource_revision.actor_user_id still references this table?
Hold a per-tenant active cap against concurrent creates
A tenant on the standard plan may hold at most 50 resources with status='active'. The create handler runs SELECT count(*) FROM resource WHERE tenant_id = $1 AND status = 'active', compares to 50, then inserts. Two creates arrive 3 ms apart on different instances and the tenant lands at 51. Name the anomaly, say whether PostgreSQL 16 READ COMMITTED or REPEATABLE READ prevents it and why, then give an implementation that holds the cap at READ COMMITTED with the exact statements. Finally, say what changes when the cap is 'at most one running export per tenant' on job_run.
Approach
- Name it: write skew. The two transactions read an overlapping set and write disjoint rows, so there is no row-level conflict for the engine to detect and each commit is individually legal.
- Rule out the levels precisely. READ COMMITTED takes a fresh snapshot per statement and takes no lock on the counted rows, so both see 49. PostgreSQL's REPEATABLE READ is snapshot isolation: it removes non-repeatable reads and phantoms within the snapshot but still admits write skew, because the anomaly is not a re-read of a changed row, it is a read of a set that a concurrent transaction invalidates. Only SERIALIZABLE closes it, by tracking the read dependency and aborting one transaction with SQLSTATE 40001 — a guarantee that exists only if the application re-runs the whole transaction from the read.
- Convert the set predicate into a single-row conflict: keep tenant.active_resource_count and run UPDATE tenant SET active_resource_count = active_resource_count + 1 WHERE tenant_id = $1 AND active_resource_count < 50 in the same transaction as the INSERT. Zero affected rows is the cap, returned as 409. The row lock serialises the decision at any isolation level, and contention is bounded to one tenant's row — which is also the fair-scheduling unit, unlike a global counter that would convoy every tenant behind one row.
- State the cost you just took on: a counter is a second source of truth that can drift, so every path that changes status must adjust it inside the same transaction, and a periodic reconciliation has to exist, with resource_revision as the authority for what the count should have been.
Follow-up
- A resource moves from archived back to active. Which statements change, and what breaks if the counter update and the status change land in different transactions?
- The cap becomes plan-dependent and a plan can change mid-month. Where does the number 50 live, and who reads it?
What programming languages are you proficient in, and how have you applied them in projects?
What programming languages are you proficient in, and how have you applied them in projects?
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 bug you encountered and how you resolved it.
Describe a challenging bug you encountered and how you resolved it.
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 in your projects?
How do you ensure code quality and maintainability in your projects?
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 experience do you have with version control systems like Git?
What experience do you have with version control systems like Git?
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?
Given a specific software problem, how would you approach finding a solution?
Given a specific software problem, how would you approach finding a solution?
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?
One customer endpoint stalls deliveries to every other destination
The egress service delivers about 1.5k webhooks/second across 40,000 destinations, with a per-destination concurrency cap of 4 and a 10-second connect-plus-read timeout. Throughput falls to 300/second, queue depth climbs, and p99 delivery latency for unaffected destinations goes from 200 ms to minutes, while the error rate barely moves. One tenant holds 900 destination rows whose URLs share a hostname that now answers in 9.5 seconds. Explain the mechanism with the arithmetic, then give the containment in the order you would apply it.
Approach
- Look at saturation before errors. A flat error rate with collapsing throughput says nothing is failing, things are waiting, so the first signal to pull is in-flight request count or pool wait time rather than the error counter. This is the distinction that decides the whole investigation.
- Group in-flight work by resolved host, not by destination id. The cap is keyed per destination row, so 900 rows sharing one hostname buy 3,600 concurrent slots against a single host, each held for 9.5 seconds. The bulkhead was never a bulkhead for that host, and grouping by the wrong dimension is why the dashboard looked healthy.
- Do the arithmetic in both directions. Required concurrency is arrival rate times latency, so 1.5k/second at 200 ms needs about 300 in flight, which is entirely consumed by 3,600 slow slots; conversely whatever concurrency is left sustains rate equals concurrency divided by 9.5 seconds, which is the 300/second you are seeing. Matching both numbers is what promotes this from a plausible story to the mechanism.
- Explain why the circuit breaker never helped. It opens on consecutive failures, and a 9.5-second response inside a 10-second timeout is a success. Slow is not failing, so an error-rate breaker cannot see this; you need a slow-call ratio, a deadline propagated from the caller's remaining budget, or a concurrency limiter.
Follow-up
- The host recovers to 80 ms. How long does the queue take to drain, and what does the drain do to the recovered host?
- Where should the 10-second timeout number actually come from?
Built from the rounds and topics TGS-NOPEC candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the TGS-NOPEC loop
- Write out the reported sequence: HR Screening, Technical Interviews, Phone Interviews, Web Conferencing, In-Person 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 5 reported rounds, with the weakest marked.
02Work Programming Fundamentals
- Spend the session on Programming Fundamentals, which TGS-NOPEC candidates report being tested on.
- Write one worked example in Programming Fundamentals and time yourself on it.
Deliverable: One timed worked example in Programming Fundamentals.
03Work Basic Programming Knowledge (Core Concepts)
- Spend the session on Basic Programming Knowledge (Core Concepts), which TGS-NOPEC candidates report being tested on.
- Write one worked example in Basic Programming Knowledge (Core Concepts) and time yourself on it.
Deliverable: One timed worked example in Basic Programming Knowledge (Core Concepts).
04Work Technical Screening Exams
- Spend the session on Technical Screening Exams, which TGS-NOPEC candidates report being tested on.
- Write one worked example in Technical Screening Exams and time yourself on it.
Deliverable: One timed worked example in Technical Screening Exams.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the software development lifecycle and your experience with it.
- Answer aloud, timed: What programming languages are you proficient in, and how have you applied them in projects?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Problem-Solving / Case Studies
- Answer aloud, timed: Given a specific software problem, how would you approach finding a solution?
- Answer aloud, timed: Describe a time when you had to make a trade-off between performance and maintainability.
Deliverable: Spoken answers to 2 reported Problem-Solving / Case Studies question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a situation where you worked in a team to achieve a common goal.
- Answer aloud, timed: How do you handle feedback and criticism from peers or supervisors?
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.
Explain the software development lifecycle and your experience with it.
Explain the software development lifecycle and your experience with 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 time when you had to make a trade-off between performance and maintainability.
Describe a time when you had to make a trade-off between performance and maintainability.
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 would you handle conflicting requirements from different stakeholders?
How would you handle conflicting requirements from different stakeholders?
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 worked in a team to achieve a common goal.
Describe a situation where you worked in a team to achieve a common goal.
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 from peers or supervisors?
How do you handle feedback and criticism from peers or supervisors?
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 provide an example of when you took the initiative on a project?
Can you provide an example of when you took the initiative on a 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?
- 01
Explain the software development lifecycle and your experience with it.
- 02
Describe a time when you had to make a trade-off between performance and maintainability.
- 03
How would you handle conflicting requirements from different stakeholders?
- 04
Describe a situation where you worked in a team to achieve a common goal.
What is the typical difficulty level of interviews at TGS-NOPEC?
The interviews are generally considered to be of moderate difficulty, focusing on both technical skills and behavioral assessments. Candidates typically report that preparation in coding and problem-solving is crucial for success.
TGS-NOPEC Software Engineer candidate reports ↗How long does the interview process usually take?
The timeline from the initial screening to the final offer can vary but often spans several weeks. It's essential to be patient and remain engaged throughout the process.
TGS-NOPEC Software Engineer candidate reports ↗What qualities differentiate successful candidates?
Successful candidates demonstrate strong technical skills and the ability to communicate effectively with team members. They also show a willingness to learn and adapt in a fast-paced environment.
TGS-NOPEC Software Engineer candidate reports ↗What is the company culture like at TGS-NOPEC?
The culture emphasizes collaboration, respect, and innovation. Employees are encouraged to contribute ideas and work together to solve complex problems.
TGS-NOPEC Software Engineer candidate reports ↗What topics does TGS-NOPEC test in interviews?
TGS-NOPEC interviews most often cover Sales domain knowledge, Programming Fundamentals, Sales role experience evaluation, Basic Programming Knowledge (Core Concepts), and Product communication. The exact emphasis depends on the specific role you apply for.
TGS-NOPEC 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.
- 01TGS-NOPEC 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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