At Infinity Systems Engineering, a Software Engineer does not work in a vacuum. Instead, you will design, develop, and integrate software that directly powers cutting-edge aerospace, space, and defense systems. This role is highly multidisciplinary, bridging the gap between traditional software development, systems engineering, and hardware integration. Whether you are working on flight control algorithms, ground station networks, or model-based system architectures, your code will support mission-critical operations where failure is not an option. The impact of this position is felt across national security and space exploration initiatives. By building high-reliability software, you enable seamless communication between complex orbital assets and ground networks. The work is challenging, intellectually stimulating, and requires a deep appreciation for safety-critical systems, real-time operating systems, and robust software architecture. For candidates who thrive on seeing their code interact with physical systems and complex aerospace frameworks, Infinity Systems Engineering offers a unique environment. You will work alongside systems, RF, and aerospace engineers to turn complex mission requirements into functional, high-performance software. It is a collaborative, fast-paced environment where technical precision and operational mission success are the ultimate goals.
Application Review
reportedThe process begins within a week of your application when a hiring manager reaches out.
What to demonstrate
- The process begins within a week of your application when a hiring manager reaches out
- Depth in Software Engineering (General)
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.
On-site Interview
reportedA one-hour conversational interview with three engineering leads covering technical, behavioral, and domain-specific questions.
What to demonstrate
- A one-hour conversational interview with three engineering leads covering technical, behavioral, and domain-specific questions
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: What is your experience with Model-Based Systems Engineering (MBSE), and how do you translate system models into executable code?
- Answer aloud and timed: How would you design a software architecture for a ground station that must process high-rate telemetry data from multiple satellites simultaneously?
Office Tour
reportedCandidates are often given a tour of the office space after the interview.
What to demonstrate
- Candidates are often given a tour of the office space after the interview
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: Explain your approach to writing unit tests for code that interfaces with legacy systems or proprietary hardware.
- Answer aloud and timed: Describe a situation where you had to work with a systems or hardware engineer who had different priorities than the software team. How did you align?
Rapid Hiring Decision
reportedA quick decision is made regarding the candidate's fit for the role.
What to demonstrate
- A quick decision is made regarding the candidate's fit for the role
- Depth in Software Engineering (General)
How to prepare
- Answer aloud and timed: Tell me about a time you faced a highly ambiguous technical requirement. What steps did you take to clarify the scope and deliver the software?
- Answer aloud and timed: How do you handle receiving critical feedback on your code or system design during a peer review?
PracHub editorial advice for the preparation topics above.
Prepare for follow-on questions
Do not just give surface-level answers. The interview panel will actively probe your responses to understand your depth of knowledge and how you handle technical scrutiny.
Highlight your multidisciplinary experience
Emphasize any past work where you had to collaborate with systems, hardware, or network engineers. Showing that you understand the "bigger picture" of a project is highly valued.
Show enthusiasm for the mission
Infinity Systems Engineering works on critical space and defense programs. Demonstrating a genuine interest in aerospace, satellite systems, or digital engineering can make a strong impression on the hiring leads.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
How do you manage memory and latency constraints in a real-time, safety-critical software environment?
How do you manage memory and latency constraints in a real-time, safety-critical software environment?
Approach
- Say what the runtime actually does before reasoning about the code.
- Name what is shared across threads and what owns each piece of state.
- Identify the window where an invariant is briefly untrue.
- Distinguish a value from a reference to it, and say which one you handed out.
Follow-up
- What happens if two callers reach this at the same time?
- Where could this allocate more than you expect?
Collapse a redelivered event batch into per-aggregate high-water marks
You drain a batch of up to 5,000,000 events, each (aggregate_id BIGINT, aggregate_version INT, event_type, payload). The log guarantees order within one aggregate only; the batch merges 64 partitions, and a relay failover has redelivered a range, so an older version for an aggregate can appear after a newer one. Given a map of last_applied_version per aggregate, produce the events worth applying, at most one per (aggregate_id, version), plus the count discarded. Target O(n) time. State the memory for 2,000,000 distinct aggregates and what you do when it does not fit.
Approach
- One pass, one hash map from aggregate_id to the highest version kept, and a discard counter. An event whose version is at or below last_applied_version for its aggregate is dropped without further work, which is the whole reason the event carries its version rather than a delta. O(n) expected time, O(d) space in distinct aggregates.
- Keep the maximum, never the last occurrence. The redelivered range means the final appearance of an aggregate in the batch can be an older version than one seen earlier in the same batch, so last-wins applies stale state over newer state and the projection regresses with no error anywhere.
- Cost the memory instead of calling it large: an 8-byte key plus a 4-byte version is 12 bytes of payload, and an open-addressed table held at a 0.7 load factor costs roughly 17 bytes per entry before per-slot metadata, so 2,000,000 aggregates is tens of megabytes in a native layout and several times that in a runtime that boxes both key and value.
- If the distinct set exceeds memory, partition on hash(aggregate_id) mod P and reduce each partition independently. Every event for one aggregate hashes to the same partition, so the per-partition result is exact and the merge is concatenation rather than a second reduction.
Follow-up
- The payload is a patch rather than a snapshot, so applying only the highest version loses the intermediate changes. What changes in your reduction?
- How do you detect that version 7 arrived while version 6 was never delivered, and what should the consumer do about the gap?
Track a rolling failure rate per destination for circuit decisions
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
- 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.
- 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.
- 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.
- 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.
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?
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?
Denormalise tenant onto revisions and backfill it live
resource_revision (revision_id, resource_id, version, actor_user_id, change_kind, patch, request_id, created_at) has 400M rows and no tenant column; tenant_id lives only on resource. Two reads need it: a tenant-scoped audit feed ordered by created_at DESC, and an offboarding purge. Both join back to resource today. Justify adding tenant_id to resource_revision against those two reads, name the anomaly the copy introduces and the constraint that prevents it, then give the ordered migration for a live table taking 1.2k writes/second — the lock each step takes, how the backfill is batched, and where each step stops being reversible. PostgreSQL 16.
Approach
- Justify from the access path rather than from taste. Without the column, the audit feed either scans resource_revision by created_at and discards other tenants' rows, or resolves the tenant's resource_ids first and probes with them — both proportional to the tenant's whole history rather than to one page. With (tenant_id, created_at DESC, revision_id DESC) it is a seek that stops at 50 rows, and the purge becomes a ranged delete instead of a join.
- Name the cost exactly: a second copy of a fact can disagree with the first. Make the disagreement unwritable rather than documented — add UNIQUE (resource_id, tenant_id) on resource so it can serve as a foreign-key target, then FOREIGN KEY (resource_id, tenant_id) REFERENCES resource (resource_id, tenant_id) on the revision table. A revision can then only ever carry its parent's tenant.
- Step one, expand: ALTER TABLE resource_revision ADD COLUMN tenant_id BIGINT NULL, with no default, so it is a catalogue change and no rewrite. It still needs ACCESS EXCLUSIVE for an instant, and that instant queues behind the longest open transaction on the table while every later query queues behind it — set lock_timeout to 2s and retry rather than wait.
- Step two, dual-write: deploy the writer that populates tenant_id on every new revision while reads still use the join. Reversible by redeploying the previous build, because nothing reads the column yet.
Follow-up
- The backfill is half finished and a rollback is required. What state is the table in, and what does the previous build do with a half-populated column?
- How do you verify the backfill actually finished, given rows are still being inserted while it runs?
How would you design a software architecture for a ground station that must process high-rate telemetry data f
How would you design a software architecture for a ground station that must process high-rate telemetry data from multiple satellites simultaneously?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Explain your approach to writing unit tests for code that interfaces with legacy systems or proprietary hardwa
Explain your approach to writing unit tests for code that interfaces with legacy systems or proprietary hardware.
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?
Walk us through a past project where a sudden change in mission requirements forced you to refactor your softw
Walk us through a past project where a sudden change in mission requirements forced you to refactor your software architecture on a tight timeline.
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?
One log partition stops advancing while the others drain
Search results for a subset of tenants are hours stale; the rest are current. The projection consumer reports lag of zero on 15 of 16 partitions and 400,000 on one. Its error rate is flat and its CPU is idle. outbox_event has no pending rows older than a second, so the relay has published everything it holds. Identify the mechanism, give the ordered checks, and state what you do in the first ten minutes versus what you change permanently.
Approach
- Read the lag distribution first. A slow consumer lags everywhere; zero on fifteen partitions and 400,000 on one is not throughput. Idle CPU on the stuck partition means the consumer is not advancing its offset at all, which points at one message it cannot get past rather than at a rate problem.
- Exonerate the producer before touching the consumer. No pending outbox rows older than a second means the relay published, so the event exists in the log. This separates never sent from sent and never applied, which are different code paths and usually different owners.
- Read the message at the stuck offset and the handler's log lines for its event_id. A flat error rate with no progress has two explanations and you must distinguish them: the handler is throwing and the retry loop is swallowing it, or the handler is blocking on something and never returning. Idle CPU with no error lines favours the second.
- Mitigate before diagnosing further. Move the offending event to a dead-letter store and commit the offset past it. Adding consumers does nothing here, because a partition is consumed by exactly one member of the group, and the blast radius is every aggregate hashed to that partition, not only the aggregate that produced the bad event.
Follow-up
- The dead-lettered event carried aggregate_version 7 and the projection had applied 6. What must the replay do differently if 8 and 9 landed in the meantime?
- How do you show staleness to the user while the partition is behind, given the API already returns the projection's watermark?
Built from the rounds and topics Infinity Systems Engineering candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Infinity Systems Engineering loop
- Write out the reported sequence: Application Review, On-site Interview, Office Tour, Rapid Hiring Decision.
- 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 Software Engineering (General)
- Spend the session on Software Engineering (General), which Infinity Systems Engineering candidates report being tested on.
- Write one worked example in Software Engineering (General) and time yourself on it.
Deliverable: One timed worked example in Software Engineering (General).
03Work Model-Based Systems Engineering (MBSE)
- Spend the session on Model-Based Systems Engineering (MBSE), which Infinity Systems Engineering candidates report being tested on.
- Write one worked example in Model-Based Systems Engineering (MBSE) and time yourself on it.
Deliverable: One timed worked example in Model-Based Systems Engineering (MBSE).
04Work Systems Engineering
- Spend the session on Systems Engineering, which Infinity Systems Engineering candidates report being tested on.
- Write one worked example in Systems Engineering and time yourself on it.
Deliverable: One timed worked example in Systems Engineering.
05Answer out loud: Technical & Domain Integration
- Answer aloud, timed: How do you manage memory and latency constraints in a real-time, safety-critical software environment?
- Answer aloud, timed: Can you describe a time you had to integrate software with physical hardware, and how you debugged communication issues?
Deliverable: Spoken answers to 2 reported Technical & Domain Integration question(s), under time.
06Answer out loud: Behavioral & Team Collaboration
- Answer aloud, timed: Describe a situation where you had to work with a systems or hardware engineer who had different priorities than the software team. How did you align?
- Answer aloud, timed: Tell me about a time you faced a highly ambiguous technical requirement. What steps did you take to clarify the scope and deliver the software?
Deliverable: Spoken answers to 2 reported Behavioral & Team Collaboration question(s), under time.
07Dry run for Infinity Systems Engineering
- Run one full mock under time, then write down the two questions you most want to ask your interviewers.
Deliverable: A completed timed mock and two questions to ask.
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.
Can you describe a time you had to integrate software with physical hardware, and how you debugged communicati
Can you describe a time you had to integrate software with physical hardware, and how you debugged communication issues?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
What is your experience with Model-Based Systems Engineering (MBSE), and how do you translate system models in
What is your experience with Model-Based Systems Engineering (MBSE), and how do you translate system models into executable code?
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 systems or hardware engineer who had different priorities th
Describe a situation where you had to work with a systems or hardware engineer who had different priorities than the software team. How did you align?
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?
Tell me about a time you faced a highly ambiguous technical requirement. What steps did you take to clarify th
Tell me about a time you faced a highly ambiguous technical requirement. What steps did you take to clarify the scope and deliver the software?
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 receiving critical feedback on your code or system design during a peer review?
How do you handle receiving critical feedback on your code or system design during a peer review?
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 prioritize tasks when supporting multiple active engineering projects or flight/ground systems?
How do you prioritize tasks when supporting multiple active engineering projects or flight/ground 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
Can you describe a time you had to integrate software with physical hardware, and how you debugged communication issues?
- 02
What is your experience with Model-Based Systems Engineering (MBSE), and how do you translate system models into executable code?
- 03
Describe a situation where you had to work with a systems or hardware engineer who had different priorities than the software team. How did you align?
- 04
Tell me about a time you faced a highly ambiguous technical requirement. What steps did you take to clarify the scope and deliver the software?
What is the format of the on-site interview?
The on-site interview typically lasts about one hour and is a panel format with three engineering leads. It is highly conversational, covering both your technical background and behavioral scenarios, with plenty of follow-on questions based on your responses.
Infinity Systems Engineering Software Engineer candidate reports ↗How quickly does Infinity Systems Engineering make hiring decisions?
The company is known for an exceptionally fast turnaround. It is common to receive an informal verbal offer as soon as the day after your on-site interview, with formal offers following shortly after.
Infinity Systems Engineering Software Engineer candidate reports ↗Do I need an active security clearance to apply?
While having an active clearance is a major plus and may be required for certain programs, the ability to obtain and maintain a security clearance is the baseline requirement for most engineering roles.
Infinity Systems Engineering Software Engineer candidate reports ↗What is the work environment and location like?
Roles are primarily located in Colorado Springs, CO, and Albuquerque, NM. The office spaces are modern and designed to support highly collaborative, multi-disciplinary engineering teams working on advanced space and defense systems.
Infinity Systems Engineering Software Engineer candidate reports ↗What topics does Infinity Systems Engineering test in interviews?
Infinity Systems Engineering interviews most often cover Software Engineering (General), Model-Based Systems Engineering (MBSE), Systems Engineering, Flight & Ground Software Engineering, and Digital Systems Engineering. The exact emphasis depends on the specific role you apply for.
Infinity Systems Engineering 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.
- 01Infinity Systems Engineering 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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