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Marathon petroleum Software Engineer Interview Guide

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

The 60-second brief

A Software Engineer at Marathon petroleum operates at the critical intersection of digital technology, operational efficiency, and large-scale industrial infrastructure. As one of the nation’s largest petroleum refining, midstream, and marketing companies, Marathon petroleum relies on robust software platforms, real-time data analytics, and operational technology (OT) integrations to keep assets running safely and efficiently. In this role, software engineers build and support platforms spanning digital workplace tools, enterprise automation, operational data pipelines, cloud infrastructure, and AI-driven predictive systems across core locations like Findlay, OH, Houston, TX, and field operational sites. The software engineering function drives measurable business impact across multiple business units.

This guide is scoped to a Software Engineer candidate at Marathon petroleum.

Focus areas

  • Behavioral Interviewing (STAR Method)
  • Conflict Management
  • Teamwork & Collaboration

The Marathon petroleum interview process

Marathon petroleum candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Phone Screen

Initial 15 to 30-minute call with Talent Acquisition or HR recruiter to discuss background, role search status, and motivations.

What to demonstrate

  • Initial 15 to 30-minute call with Talent Acquisition or HR recruiter to discuss background, role search status, and motivations
  • Depth in Behavioral Interviewing (STAR Method)

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.

Panel Interview

30 to 60-minute panel interview with HR representative, hiring managers, and senior engineers focusing on behavioral questions and past projects.

What to demonstrate

  • 30 to 60-minute panel interview with HR representative, hiring managers, and senior engineers focusing on behavioral questions and past projects
  • Depth in Behavioral Interviewing (STAR Method)

How to prepare

  • Answer aloud and timed: Give an example of a time in a group project or team environment where you had a hard time working with someone. How did you resolve the conflict?
  • Answer aloud and timed: Describe a situation where you had too many tasks or conflicting deadlines and had to prioritize your workload.

Onsite Visit

In-person visit including multiple panel discussions, facility tour, and informal meetings with future team members for specific roles.

What to demonstrate

  • In-person visit including multiple panel discussions, facility tour, and informal meetings with future team members for specific roles
  • Depth in Behavioral Interviewing (STAR Method)

How to prepare

  • Answer aloud and timed: Describe a time when you were forced to change your working style or adapt to unexpected project changes, and what was the outcome?
  • Answer aloud and timed: Tell us about how you systematically approach and solve complex, ambiguous problems.

Where candidates lose points

Master the STAR Method

Frame every behavioral answer by stating the Situation, detailing the specific Task, walking through your direct technical Actions, and clearly stating the Result (with quantitative metrics if available).

Expect Panel Format Interviews

You will routinely speak with a panel of two to four people combining HR professionals, engineering supervisors, and senior team members. Address the entire panel when answering, maintaining engaging eye contact with all participants.

Highlight Teamwork and Communication

Marathon petroleum places high value on workplace culture and cross-functional harmony. Focus your stories on how you helped your team succeed, mentored others, or bridged communication gaps between technical teams and field operations.

Avoid giving generic, high-level answers to behavioral questions

Interviewers will press for specific details regarding what action YOU individually took to resolve a problem or complete a task.

Questions & practice

Tell us about how you systematically approach and solve complex, ambiguous problems.

Medium · Problem-Solving & Operational Scenarios

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.

Follow-up

  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Find overlapping job attempts and peak concurrency from lease records

Medium · sweep line · intervals · leases

A day of job_run history yields about 50,000,000 attempt records: (job_run_id, job_type, attempt, started_at, finished_at which is NULL when the worker died, lease_expires_at). Leases expire on a clock, so a job that outran its lease ran twice. Produce (a) every job_run_id whose attempts overlapped in wall-clock time and (b) the peak number of simultaneously running attempts per job_type with the minute it occurred. Target O(n log n). State how you treat a NULL finished_at and what clock skew does to your answer.

Approach

  1. Define the interval before sorting anything: an attempt occupies [started_at, COALESCE(finished_at, lease_expires_at)). finished_at is observed and lease_expires_at is only a promise, so every attempt without a finish contributes an estimate and the whole result is a lower bound on overlap rather than an exact count.
  2. For peak concurrency, sweep: emit 2n endpoints, sort by (timestamp, kind) with ends ordered before starts at equal timestamps, then walk the sequence maintaining a counter per job_type and record each type's maximum with its timestamp. O(n log n) dominated by the sort, O(n) space, or O(1) extra if the sort is external and the walk streams.
  3. For overlap detection, do not compare attempts pairwise. A single global sort by (job_run_id, started_at) gives both the grouping and the order; within a group, keep the maximum end seen so far and report an overlap exactly when the next start is less than that running maximum, which is one linear pass after the sort.
  4. Half-open intervals matter and are easy to get wrong: with closed intervals an attempt ending at the same millisecond another begins reads as concurrency two, and across 50,000,000 records that artefact swamps the real signal.

Follow-up

  • A handler is not idempotent and you have found 400 overlapping jobs. Which of them actually caused damage, and what would you query to find out?
  • Peak concurrency for one job_type is 4 against a configured cap of 4. Is the cap working, or is the data hiding attempts that never started?

Merge partitioned event streams into one ordered feed with bounded lateness

Hard · k-way merge · watermarks · out-of-order streams

The read-model service consumes 64 log partitions carrying about 4,000 events per second in total. Each partition is ordered within itself, but partitions drift by up to 30 seconds, and the activity feed must present a tenant's events in occurred_at order. Produce the merge. State its complexity, the buffer it requires in events and in bytes, what happens when one partition is idle, and what you do with an event that arrives after you have already emitted its position. Payloads average 1 KB.

Approach

  1. Merge with a min-heap over the 64 partition heads keyed on (occurred_at, event_id): O(log P) per event and O(n log P) overall. The tie-break on event_id is what makes the output deterministic when two partitions carry the same millisecond, which matters because the feed is paginated and a non-deterministic order reorders pages under the reader.
  2. Emitting the heap head is only correct once every partition has produced everything up to that timestamp, so the emit condition is a watermark: the minimum across partitions of the highest occurred_at seen, less the allowed lateness. Events are held until the watermark passes them, which is what turns individually ordered streams into a jointly ordered one.
  3. Size the buffer from the lateness rather than guessing: 4,000 events per second times 30 seconds is 120,000 buffered events, and at 1 KB each about 120 MB of heap. That number is the real price of the ordering guarantee and belongs in front of whoever asked for it.
  4. Handle the idle partition explicitly, because it fails the feed rather than corrupting it: a partition with no traffic never advances its own maximum, so the watermark freezes and output stops entirely. Either every partition emits a periodic idle marker carrying the broker's current time, or the watermark falls back to wall clock for a partition silent beyond a threshold.

Follow-up

  • The lateness budget is raised to five minutes. What is the new buffer, and what besides memory changes?
  • The consumer restarts. Where does it resume from, and what does the feed look like for the first 30 seconds?

Keep soft-deleted accounts from blocking re-registration

Easy · soft delete · unique constraints · engine differences

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

  1. 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.
  2. 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.
  3. 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.
  4. 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?

Stop tag and share joins from fanning out a page

Medium · join fan-out · semi-joins · many-to-many

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

  1. 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.
  2. 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.
  3. 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.
  4. 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?

How would you explain a complex technical problem or system constraint to a non-technical stakeholder or busin

Medium · Problem-Solving & Operational Scenarios

How would you explain a complex technical problem or system constraint to a non-technical stakeholder or business manager?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 situation where the scope of a technical project changed mid-stream. How did you handle the change?

Medium · Problem-Solving & Operational Scenarios

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

Walk us through your resume and highlight the technical project that best demonstrates your engineering capabi

Medium · Technical Projects & Professional Experi

Walk us through your resume and highlight the technical project that best demonstrates your engineering capabilities.

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 the types of technical projects you have delivered, including project scope, timeline, and overall pe

Medium · Technical Projects & Professional Experi

Describe the types of technical projects you have delivered, including project scope, timeline, and overall performance against objectives.

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 that would be directly beneficial in supporting enterprise and operational technic

Medium · Technical Projects & Professional Experi

What experience do you have that would be directly beneficial in supporting enterprise and operational technical environments at Marathon petroleum?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

Tell us about your proudest technical accomplishment or project achievement to date.

Medium · Technical Projects & Professional Experi

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 stay up to date on new technical developments, software tools, and engineering frameworks in your f

Medium · Technical Projects & Professional Experi

How do you stay up to date on new technical developments, software tools, and engineering frameworks in your field?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

If a user or field site lost communication with a device or operational system, how would you start troublesho

Medium · Problem-Solving & Operational Scenarios

If a user or field site lost communication with a device or operational system, how would you start troubleshooting?

Approach

  1. Establish what changed and when, before forming any theory.
  2. Pick a bisection that eliminates candidates whichever way it turns out.
  3. Check the instrumentation before believing the symptom.
  4. 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?

Suggested practice checklist

Built from the rounds and topics Marathon petroleum candidates report.

Day 1 — Map the Marathon petroleum loop

  • Write out the reported sequence: Phone Screen, Panel Interview, Onsite Visit.
  • 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.

Day 2 — Work Behavioral Interviewing (STAR Method)

  • Spend the session on Behavioral Interviewing (STAR Method), which Marathon petroleum candidates report being tested on.
  • Write one worked example in Behavioral Interviewing (STAR Method) and time yourself on it.

Deliverable: One timed worked example in Behavioral Interviewing (STAR Method).

Day 3 — Work Conflict Management

  • Spend the session on Conflict Management, which Marathon petroleum candidates report being tested on.
  • Write one worked example in Conflict Management and time yourself on it.

Deliverable: One timed worked example in Conflict Management.

Day 4 — Work Teamwork & Collaboration

  • Spend the session on Teamwork & Collaboration, which Marathon petroleum candidates report being tested on.
  • Write one worked example in Teamwork & Collaboration and time yourself on it.

Deliverable: One timed worked example in Teamwork & Collaboration.

Day 5 — Answer out loud: Behavioral & Behavioral Situation (STAR Method)

  • Answer aloud, timed: Name an example of a time that you failed in a previous role and how you responded to it.
  • Answer aloud, timed: Tell me about a project you worked on recently and describe some of the major technical or logistical challenges you faced.

Deliverable: Spoken answers to 2 reported Behavioral & Behavioral Situation (STAR Method) question(s), under time.

Day 6 — Answer out loud: Problem-Solving & Operational Scenarios

  • Answer aloud, timed: Tell us about how you systematically approach and solve complex, ambiguous problems.
  • Answer aloud, timed: If a user or field site lost communication with a device or operational system, how would you start troubleshooting?

Deliverable: Spoken answers to 2 reported Problem-Solving & Operational Scenarios question(s), under time.

Day 7 — Answer out loud: Technical Projects & Professional Experience

  • Answer aloud, timed: Walk us through your resume and highlight the technical project that best demonstrates your engineering capabilities.
  • Answer aloud, timed: Describe the types of technical projects you have delivered, including project scope, timeline, and overall performance against objectives.

Deliverable: Spoken answers to 2 reported Technical Projects & Professional Experience question(s), under time.

Behavioural preparation

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

Name an example of a time that you failed in a previous role and how you responded to it.

Medium · Behavioral & Behavioral Situation (STAR

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Tell me about a project you worked on recently and describe some of the major technical or logistical challeng

Medium · Behavioral & Behavioral Situation (STAR

Tell me about a project you worked on recently and describe some of the major technical or logistical challenges you faced.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Give an example of a time in a group project or team environment where you had a hard time working with someon

Medium · Behavioral & Behavioral Situation (STAR

Give an example of a time in a group project or team environment where you had a hard time working with someone. How did you resolve the conflict?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a situation where you had too many tasks or conflicting deadlines and had to prioritize your workload

Medium · Behavioral & Behavioral Situation (STAR

Describe a situation where you had too many tasks or conflicting deadlines and had to prioritize your workload.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a time when you were forced to change your working style or adapt to unexpected project changes, and

Medium · Behavioral & Behavioral Situation (STAR

Describe a time when you were forced to change your working style or adapt to unexpected project changes, and what was the outcome?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Tell me about a time when you had to conduct research or acquire new technical skills quickly to complete a pr

Medium · Problem-Solving & Operational Scenarios

Tell me about a time when you had to conduct research or acquire new technical skills quickly to complete a project goal.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Why do you want to work for Marathon petroleum specifically?

Medium · Company Fit, Values & Career Intentions

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

What are your greatest professional strengths and your biggest areas for technical growth?

Medium · Company Fit, Values & Career Intentions

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

How do you feel about working in cross-functional teams with field engineers, operations staff, and corporate

Medium · Company Fit, Values & Career Intentions

How do you feel about working in cross-functional teams with field engineers, operations staff, and corporate management?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

What type of work environment do you perform best in, and what do you expect from team leadership?

Medium · Company Fit, Values & Career Intentions

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Where do you see your engineering career progressing over the next three to five years?

Medium · Company Fit, Values & Career Intentions

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?