General Atomics · Software Engineer
Updated · 2026-09-24

General Atomics Software Engineer
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

As a Software Engineer at General Atomics, you develop the critical software systems that power advanced defense, aerospace, and energy technologies. Your work directly enables unmanned aerial vehicles (UAVs) like the MQ-9B SkyGuardian and Predator series, flight control systems, electromagnetic systems, and ground control stations. In this role, software is not merely an abstraction—it is directly tied to hardware, embedded electronics, sensors, and flight dynamics operating under strict real-time constraints where safety, precision, and reliability are absolute requirements.

Getting the code to run is the floor. What usually separates answers is the case checked without prompting: empty input, a single element, duplicate keys, or a value that overflows the integer type you chose.

General Atomics candidates report 3 rounds · ≈ 3-5 weeks. The stages below are what candidates describe, not a published process.

Make every write idempotent under retryBound every outbound call with a timeoutTrace a symptom to a mechanism under load

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See the practice prompts

14Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

As a Software Engineer at General Atomics, you develop the critical software systems that power advanced defense, aerospace, and energy technologies. Your work directly enables unmanned aerial vehicles (UAVs) like the MQ-9B SkyGuardian and Predator series, flight control systems, electromagnetic systems, and ground control stations. In this role, software is not merely an abstraction—it is directly tied to hardware, embedded electronics, sensors, and flight dynamics operating under strict real-time constraints where safety, precision, and reliability are absolute requirements.

The impact of this role reaches across national security and airborne technology. Software engineers at General Atomics write high-performance C and C++ code, design complex hardware-software interfaces, implement low-level networking and communication protocols, and build algorithms for flight automation and telemetry. Whether you join a Flight Controls Production team, Ground Control Systems group, or Sensor Integration team, your codebase will be deployed to mission-critical hardware where efficiency and system stability are essential.

This position demands both strong theoretical foundations and practical, low-level engineering capability. You will collaborate closely with cross-functional teams including systems engineers, electrical engineers, mechanical designers, and flight test crews. For engineers who thrive on low-level system design, embedded hardware integration, and real-time execution, General Atomics provides a challenging and impactful environment where software directly commands physical systems in the air and on the ground.

01

Phone Screen

reported

The title covers product work, platform work, infrastructure, mobile and frontend, and those are different jobs with different loops behind them. A screening call is the cheapest place to find out which one the seat is, and asking reads as experienced rather than fussy. The questions that separate them: what the team is on call for, what the last three projects were, and whether any round happens inside an existing repository instead of a blank file. Then say which of that you have done and which you have not. Claiming the whole posting is the fastest way to be found out one round later.

What to demonstrate

  • Whether you can locate your experience inside one flavour of the role honestly instead of claiming the entire requirements list
  • Whether you name what you have not done, which an experienced screener reads as a level signal and can plan the loop around
  • Whether what you want next matches what the seat is: someone who wants greenfield work landing on a team that mostly operates an existing system is a hire that leaves within the year

How to prepare

  • Mark every line of the posting as done, adjacent or new, and write one sentence for each adjacent line naming the closest thing you actually built
  • Split your last two years into rough percentages across feature work, operating and debugging live systems, and design or review, so a question about scope gets numbers rather than adjectives
  • Bring three questions that discriminate between seats: what the team is paged for, how much of the work is changing existing code versus standing up something new, and what shipped in the last quarter
PracHub interview research ↗
02

Technical Interviews

reported

The same problem is scored by two different mechanisms depending on the format, and preparing for one does not cover the other. With a person watching, partial progress is visible and a hint is a correction you can absorb; silence is the expensive failure, because nobody can read a half-written function. With an automated grader there is no partial credit for what you were about to do, nobody to ask, and the worked examples in the prompt are the entire specification. Read them as a contract, down to whether an empty result should be an empty list or no output at all.

What to demonstrate

  • In a live session, whether your commentary tracks what your hands are doing, and whether a hint redirects you or gets defended against
  • In an automated one, whether you cover the cases the examples do not show, since the hidden cases are where the score moves
  • Whether you manage the clock on purpose: abandoning an approach that is not converging while there is still time to write something simpler that finishes

How to prepare

  • Have someone hand you a problem and feed you one deliberately wrong hint. Practise testing it against a concrete case instead of accepting or rejecting it on authority.
  • Do one timed run a week in a plain browser editor with autocomplete, linting and your own snippets switched off, which is closer to what these environments give you
  • For the automated format, write the harness before the solution: a main that feeds the worked examples plus an empty and a single-element case and prints expected against actual, so a wrong submission is caught by you first
PracHub interview research ↗
03

Onsite Interview

reported

Coding rounds mostly set a floor. They decide whether you clear the bar, not where you land on the ladder. Level tends to come out of the design discussion and the ownership stories, so the question worth auditing beforehand is whether the scope you describe matches the scope of the job. Work that stops at your own service, or a story whose hard part was writing the code rather than getting several people to agree on an interface, reads a level below where you think you are interviewing, and that gap is usually resolved downwards.

What to demonstrate

  • Whether the largest thing you describe owning ran end to end — the decision, the migration path, the rollout, and what you did when it went wrong — or stopped at the change you merged
  • Whether design answers include what you would not build, what you would defer, and what you would measure before committing, rather than only what the boxes are
  • Whether a disagreement in a story was settled with something checkable — a benchmark, a prototype, a written proposal — instead of by seniority or by waiting it out
  • Whether you can say which calls you made alone and which you escalated, and why the line sat where it did

How to prepare

  • Write your largest piece of owned work as a timeline of decisions — who decided what, when, and what you did when the plan broke — then delete every sentence whose subject is "we" and see how much survives
  • Take one system you know well and drill the migration answer: how old and new paths run side by side under live traffic, how you compare their outputs, what the rollback is once writes are going to both, and which step you would not automate
  • Map each line of the ladder in the job posting to a specific thing you have done, find the line you cannot support, and prepare the closest evidence you have plus an honest account of the gap
PracHub interview research ↗

PracHub editorial advice for the preparation topics above.

01

Shipping a migration and the code that depends on it as a single change

During any rolling deploy, and for as long as a rollback remains possible, old and new code execute against the same schema at the same time. A migration that drops or renames a column breaks every instance that has not restarted yet, and code that requires a column the migration has not applied breaks every instance that restarted early. The discipline is expand then contract: add the new column nullable, write both shapes, backfill in batches, move reads across once the backfill is verified, and only then stop writing the old shape and drop it - four deploys, usually spread over days. It feels disproportionate until the first rollback, at which point it is the only reason the previous version still runs.

02

Assuming an isolation level prevents the anomaly you actually have

Isolation levels are named by the SQL standard but implemented differently, so any claim about one is only true of a named engine. PostgreSQL defaults to READ COMMITTED, where every statement takes a fresh snapshot, so two statements inside one transaction can legitimately disagree about the same row. Its REPEATABLE READ is snapshot isolation: it removes non-repeatable and phantom reads but permits write skew, where two transactions each read a set, each conclude their own write is safe, both commit, and the combined result violates a constraint that no single row expresses. Only SERIALIZABLE closes that, and it closes it by aborting a transaction with a serialization failure (SQLSTATE 40001), which means the guarantee is theoretical unless the application has a retry loop. InnoDB's REPEATABLE READ is a different mechanism again - plain SELECTs read a consistent snapshot while locking reads and writes see the latest committed row - so a read-modify-write inside one transaction can act on a value that the transaction's own earlier SELECT never returned.

03

Never running a concrete value through the code

Trace one small input and one edge input by hand, index by index, out loud. Re-reading your own code catches design mistakes; walking a real value through it catches the off-by-one, the uninitialised accumulator and the loop that never advances.

04

Tests that assert on the implementation rather than the behaviour

Assert on what a caller can observe, not on the number of internal calls or the shape of a private field. A test that breaks on every refactor but still passes when the answer is wrong costs more than it protects.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

11 technical prompts3 include a worked solution

How do pointers work in C/C++, and how do you perform pointer arithmet…

medium
languages, concurrency and fundamentals

How do pointers work in C/C++, and how do you perform pointer arithmetic safely when traversing buffers?

Approach
  1. Say what the runtime actually does before reasoning about the code.
  2. Distinguish a value from a reference to it, and say which one you handed out.
  3. Name what is shared across threads and what owns each piece of state.
Follow-up
  • Where could this allocate more than you expect?
  • What happens if two callers reach this at the same time?

How do static variables behave when declared inside a function versus …

medium
languages, concurrency and fundamentals

How do static variables behave when declared inside a function versus globally in a C file?

Approach
  1. Identify the window where an invariant is briefly untrue.
  2. Say what the runtime actually does before reasoning about the code.
  3. Name what is shared across threads and what owns each piece of state.
Follow-up
  • How would you prove the race exists rather than suspect it?
  • Where could this allocate more than you expect?

What is the difference between a `struct` and a `class` in C++, and ho…

medium
languages, concurrency and fundamentals

What is the difference between a struct and a class in C++, and how does access control differ by default?

Approach
  1. Reach for the cheapest primitive that closes the race, not the broadest lock.
  2. Identify the window where an invariant is briefly untrue.
  3. Name what is shared across threads and what owns each piece of state.
Follow-up
  • What happens if two callers reach this at the same time?
  • How would you prove the race exists rather than suspect it?

Explain memory allocation differences between C and C++ (`malloc`/`fre…

medium
languages, concurrency and fundamentals

Explain memory allocation differences between C and C++ (malloc/free versus new/delete), and how memory layout works in stack versus heap allocation.

Approach
  1. Identify the window where an invariant is briefly untrue.
  2. Distinguish a value from a reference to it, and say which one you handed out.
  3. Say what the runtime actually does before reasoning about the code.
Follow-up
  • Where could this allocate more than you expect?
  • What happens if two callers reach this at the same time?

Track a rolling failure rate per destination for circuit decisions

easyWorked solution
sliding windowring buffercircuit breaker

The egress service delivers about 1,500 webhooks per second across roughly 40,000 destinations, each call bounded by a 10 second timeout. Maintain, per destination, the failure rate over the trailing 60 seconds so a caller can ask before dispatch whether the circuit should open. Attempts arrive as (destination_id, finished_at_ms, outcome). Requirement: amortised O(1) per attempt, with total memory bounded by the destination count rather than by traffic. Give the structure, its exact memory, and the rule that stops a destination with three attempts from opening a circuit.

Approach
  1. Name the exact-deque version and then reject it as the default. Holding timestamps and advancing a tail pointer past anything older than now minus 60 seconds is a correct two-pointer window at amortised O(1) per attempt, but its memory tracks in-window traffic, so one destination in a retry storm holds hundreds of thousands of entries while thousands of quiet destinations hold none.
  2. Use a ring of 60 one-second buckets per destination, each bucket a pair of counters for attempts and failures. On an attempt, advance the ring by the elapsed whole seconds, zeroing at most min(elapsed, 60) buckets, then increment the head. That is amortised O(1) with a fixed footprint per destination.
  3. State the footprint: 60 buckets times two 4-byte counters is 480 bytes of payload per destination, so 40,000 destinations is roughly 20 to 25 MB with per-entry overhead, bounded by the catalogue rather than by the rate. The cost is granularity, since the oldest bucket ages out in whole seconds, which is far tighter than the decision needs.
  4. Require a minimum sample before the circuit may open. A destination with three attempts and three failures reads as 100 percent and is not evidence; a floor of roughly 20 attempts in the window makes the ratio meaningful, and below that floor use a run of consecutive failures as the trigger instead.
  5. Expire idle destinations, or memory grows with every destination ever seen rather than with the live set. Hold the rings in a bounded LRU keyed on destination_id and treat a miss as no history, which is the correct default for an endpoint that has been silent for a minute.
  6. Keep the half-open probe out of the window arithmetic. After the circuit opens, one probe per interval decides whether to close it, and folding that single success into a window that still holds a 100 percent failure history would reopen the destination on one data point.
Worked solution 20 min
  1. Define the bucket struct and the advance step: take floor(finished_at_ms / 1000), compare with the ring's current second, zero min(delta, 60) buckets forward, then write into the new head.
  2. Trace a destination that receives 5 attempts, goes silent for 90 seconds, then receives one more, and confirm the rate is computed from one attempt rather than six.
  3. Compute total memory for 40,000 destinations at 60 buckets of two 4-byte counters, and state what changes if the window widens to 300 seconds.
  4. Write the open rule as a single predicate combining the minimum-attempt floor with the rate threshold.
EXPECTED RESULTA per-destination ring of 60 one-second (attempts, failures) buckets advanced lazily for amortised O(1) cost, roughly 480 bytes of counters per destination and about 20 to 25 MB for 40,000 of them, an LRU bound on live rings, and an open rule requiring both a minimum attempt count in the window and a rate above threshold.
Follow-up
  • The fleet is 30 instances and each sees roughly a thirtieth of a destination's traffic. Where does the rate actually live, and what does a per-instance answer get wrong?
  • A destination answers in 9.5 seconds and succeeds. It is not failing but it is consuming your per-destination concurrency. What signal should open the circuit here?
  • How would you make the window survive a process restart, and is it worth the cost?

Day one measures instead of guessing, under a fixed rubric, and the remaining hours are allocated in proportion to the gaps before any studying begins. The allocation is deliberately not renegotiated midweek, because the area that feels worst on day three is usually the one that is moving.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Diagnostic, scored before you study anything
  • Sit a 110-minute diagnostic in four blocks: forty-five minutes on two coding problems, twenty-five on one design prompt taken to interface and data model, twenty of short-answer fundamentals, and twenty delivering two behavioural answers aloud.
  • Score each block from 0 to 3 on a fixed rubric where 3 is correct and fluent, 2 is correct but slow or prompted, 1 is partially correct and 0 is stuck, grading the artifact rather than how the attempt felt.
  • Allocate days two to five in proportion to 3 minus each block's score, write the allocation down, and commit to leaving it alone.

Deliverable: A scored rubric and a fixed hour allocation for the rest of the week.

Practice prompt ↗Practice prompt ↗Worked solution ↗
02Largest gap: find the boundary rather than the subject
  • Split the weakest area into named sub-skills and rate each separately. For coding those are restating the problem, choosing the structure, stating the invariant, turning the invariant into loop bounds, handling empty and single-element input, and accounting for complexity out loud.
  • Attempt three items positioned just above where the rating drops off, and for each write the first move you failed to make.
  • Re-attempt one of them from blank four hours later with nothing open.

Deliverable: A sub-skill map with the two blocking sub-skills circled.

Practice prompt ↗Practice prompt ↗
03Drill the blocking sub-skill by repeating the shape
  • Do eight short repetitions of the same shape rather than eight different problems, so what gets practised is the pattern and not the puzzle.
  • State the rule you now hold in one sentence, then test it against a case built to break it, a sliding window over an array containing negative values, or a cache-aside read path whose invalidation message is dropped.
  • Have someone else read your one-sentence rule and find the precondition you left out.

Deliverable: One rule statement with its preconditions attached and one counterexample that would have caught the incomplete version.

Practice prompt ↗Practice prompt ↗
04Second gap, plus maintenance on the strongest area
  • Run the same sub-skill decomposition on the second-largest gap in half the time.
  • Spend twenty-five timed minutes on the block you scored highest, choosing the hardest item you can still finish rather than a warm-up.
  • Write whether each area fails you on recall, on setup, or on execution, and set the fix accordingly: repetition for recall, a written checklist for setup, timed work for execution.

Deliverable: A second sub-skill map plus a one-line failure diagnosis for each area.

Practice prompt ↗Practice prompt ↗Worked solution ↗
05The gap that is not a skill
  • Record one technical and one behavioural answer, then count two things in the playback: seconds before your first clarifying question, and sentences you began without knowing where they would end.
  • Practise saying that you do not know, followed by how you would find out, without letting it soften into a guess, and practise stating a complexity or an estimate before being asked for it.
  • Redeliver one answer under a hard ninety-second cap, which forces structure ahead of detail.

Deliverable: Two recordings with a counted reduction in time-to-first-question.

Practice prompt ↗Practice prompt ↗
06Retest under day-one conditions
  • Sit the same 110-minute structure with new prompts of comparable difficulty and score it on the identical rubric.
  • For any block that did not move, change the method rather than adding hours: a block stuck at 1 usually means the practice was too varied, not too short.
  • Write down which single block you would still lose the offer on.

Deliverable: A second scored rubric placed beside the first, with one named remaining risk.

Practice prompt ↗Practice prompt ↗
07Full loop under interview conditions
  • Run a sixty-minute mock over the two blocks that moved least, with an interviewer briefed to interrupt and change direction mid-answer.
  • Write the recovery script for going blank: restate the question, state your assumption, name the first thing you would check.
  • Say every rule from the week aloud without reading it, and cut any you cannot state in a single sentence, since a rule you have to reconstruct mid-answer will not survive an interruption.

Deliverable: A one-page card holding the recovery script and only the rules you could state from memory.

Practice prompt ↗Practice prompt ↗Worked solution ↗

Expand any day for tasks and deliverables. Your progress is saved on this device.

Nobody is scoring your stamina at three in the morning. What carries weight is which signal told you something was wrong, what you measured before touching anything, what you rolled back versus what you fixed forward, and why you picked one. 'We restarted it and it went away' is a story about not knowing.

Tell me about a time you had to learn a new programming language, hard…

medium
behavioural and engineering judgement

Tell me about a time you had to learn a new programming language, hardware interface, or domain knowledge quickly to complete a task.

Approach
  1. State the situation in two sentences and spend the rest on the reasoning.
  2. Close with what you would do differently, concretely.
  3. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What did you decide not to do, and why?
  • What would you do differently if you ran that again?

Describe a conflict you had with a team member or project lead regardi…

medium
behavioural and engineering judgement

Describe a conflict you had with a team member or project lead regarding a design choice, and how you reached a resolution.

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. Close with what you would do differently, concretely.
Follow-up
  • How did you know your change caused the improvement?
  • What would you do differently if you ran that again?

Turn a code review disagreement into a decision

easy
code reviewoptimistic concurrencycommunication

A colleague's change updates a row with UPDATE resource SET version = version + 1 WHERE resource_id = $1 AND version = $2 and treats an affected-row count of zero as a successful no-op. You read that as a silently lost update; they think returning 200 is friendlier to clients than returning a conflict. Describe how you have handled a review disagreement of this shape: what goes in the comment, when you leave the thread, and who decides. Then write the comment you would leave here, in under 80 words.

Approach
  1. Sort the disagreement before writing anything. A silently discarded write is a correctness claim about data; the choice between 409 and 412 is taste. Only the first justifies blocking a merge, and saying which one you are doing is most of the value of the comment.
  2. Make the claim reproducible in the comment itself with an interleaving rather than a principle: A reads version 7, B reads version 7, B commits version 8, A's predicate matches zero rows, A is told it succeeded and A's edit is gone.
  3. Offer the alternative with its cost attached: return 409 carrying the current version and the revision that won, so the client can re-read and re-apply. Note that automatic retry is not the fix, because a retry re-reads the winner's state and reapplies an intent formed against data that no longer exists.
  4. Apply an escalation rule you can state: two round trips on the thread, then a call, and the service's owner decides rather than the reviewer. A reviewer who cannot be overruled is a bottleneck with extra steps.
  5. Close in writing wherever the decision lands, so the next reader finds the reasoning in the code or the ticket instead of in a collapsed review thread.
Follow-up
  • Where would you put the test that fails if someone reintroduces the swallowed zero rowcount?
  • The author says clients cannot handle a 409. How do you check whether that is true?
  • How do you handle the same review comment when the author is more senior than you and in a hurry?
  • 01

    Tell me about a time you had to learn a new programming language, hardware interface, or domain knowledge quickly to complete a task.

  • 02

    Describe a conflict you had with a team member or project lead regarding a design choice, and how you reached a resolution.

  • 03

    A colleague's change updates a row with UPDATE resource SET version = version + 1 WHERE resource_id = $1 AND version = $2 and treats an affected-row count of zero as a successful no-op. You read that as a silently lost update; they think returning 200 is friendlier to clients than returning a conflict. Describe how you have handled a review disagreement of this shape: what goes in the comment, when you leave the thread, and who decides. Then write the comment you would leave here, in under 80 words.

PracHub interview preparation framework ↗
Is this an official General Atomics interview guide?

No. It is PracHub's own research and practice material for the Software Engineer role at General Atomics. Rounds and questions reflect what candidates have reported, not a process General Atomics has published, and they change over time. Confirm the current format and scope with your recruiter.

PracHub interview research ↗
How difficult are the technical interviews at General Atomics compared to Big Tech?

Interviews at General Atomics focus less on abstract LeetCode algorithms and more on practical C/C++ fundamentals, system architecture, pointers, and memory management. The difficulty lies in the breadth of low-level details and the depth of questioning during resume project reviews.

PracHub interview research ↗
Is U.S. Citizenship strictly required for Software Engineer roles?

Yes, for the vast majority of software engineering positions at General Atomics Aeronautical Systems, U.S. Citizenship is mandatory due to federal defense contracts and Department of Defense security clearance requirements.

PracHub interview research ↗
What should I expect during the coding assessment component?

You will typically work on a real computer or whiteboard to solve a practical task, such as writing a C/C++ program to parse binary data packets, implement a buffer, or manipulate arrays using pointers. Evaluators look for clean code, correct logic, and your ability to explain your thought process.

PracHub interview research ↗
How long does the hiring process usually take from start to finish?

The typical timeline ranges from 3 to 6 weeks. However, because defense staffing requirements depend on contract schedules and security background checks, response times between interview stages can occasionally extend longer.

PracHub interview research ↗
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.