As a Software Engineer at First horizon bank, you are a critical contributor to the technological infrastructure that powers our financial services. You will be tasked with developing, maintaining, and scaling high-performance applications that serve a diverse client base. Your work directly impacts how our users interact with their financial data, ensuring security, reliability, and seamless performance in a highly regulated industry. This role requires a balance of technical precision and business acumen. You will not only write clean, efficient code but also collaborate with cross-functional teams to translate complex business requirements into robust software solutions. Whether you are working on internal tools or customer-facing platforms, your contributions will be vital to maintaining our competitive edge in the financial sector. ##### Tip The environment at First horizon bank is highly professional. Expect your interviewers to value clear, concise communication and a disciplined approach to problem-solving.
Screening Call
reportedInitial call from an HR representative to discuss your background, interest in the company, and logistical details.
What to demonstrate
- Initial call from an HR representative to discuss your background, interest in the company, and logistical details
- Depth in Take-home coding assessment
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 Assessments
reportedIncludes a take-home coding assignment to evaluate your technical skills.
What to demonstrate
- Includes a take-home coding assignment to evaluate your technical skills
- Depth in Take-home coding assessment
How to prepare
- Answer aloud and timed: How do you handle tight deadlines or shifting project requirements?
- Answer aloud and timed: Why do you want to join the engineering team at First horizon bank?
Onsite/Virtual Interview
reportedMeet with members of the engineering team to discuss your experience, technical approach, and cultural alignment.
What to demonstrate
- Meet with members of the engineering team to discuss your experience, technical approach, and cultural alignment
- Depth in Take-home coding assessment
How to prepare
- Answer aloud and timed: Can you explain your approach to writing scalable and maintainable code?
- Answer aloud and timed: How do you ensure the security of the applications you develop?
PracHub editorial advice for the preparation topics above.
Structure your answers
Use the STAR method (Situation, Task, Action, Result) for behavioral questions to keep your responses focused and impactful.
Prepare your own questions
Always have 3–5 thoughtful questions ready for your interviewers about the team’s current tech stack, the biggest challenges they are currently facing, or the company culture.
Be transparent about your experience
If you don't know an answer, it is better to explain how you would find the solution rather than guessing.
Mind your communication
In a professional environment like First horizon bank, your ability to communicate complex technical ideas to non-technical stakeholders is a significant advantage.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Merge partitioned event streams into one ordered feed with bounded lateness
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
- 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.
- 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.
- 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.
- 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?
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?
Canonicalise a request body into a stable idempotency fingerprint
idempotency_key.request_fingerprint is a SHA-256 over the method, path and canonicalised body, and a retry whose fingerprint differs must be rejected with 422 rather than served the stored response. Write the canonicaliser. Bodies are JSON up to 256 KB nested at most 32 levels; clients vary key order, whitespace and unicode escaping, and some send 64-bit ids as JSON numbers. Produce a deterministic byte string such that semantically identical bodies match and any semantic difference does not. State your complexity and name two normalisations you refuse to perform.
Approach
- Parse once into a tree, then re-serialise under fixed rules: object keys sorted, array order preserved, one escaping convention, no insignificant whitespace. Parsing is O(n) and sorting keys is O(k log k) per object, so O(n log n) overall with O(depth) stack, and the 32-level cap is enforced during parsing because hostile nesting is how a canonicaliser becomes a stack overflow.
- Sort keys by their UTF-8 bytes and say why the obvious implementation is wrong in some runtimes: a default string comparison that orders by UTF-16 code units places surrogate pairs, meaning code points from U+10000 up, below U+E000 to U+FFFF, which is not UTF-8 byte order, so two services written in different languages disagree on the same document.
- Do not re-encode numbers through a double. IEEE-754 binary64 represents integers exactly only up to 2^53, so normalising a 19-digit id through a float changes it, and 1 against 1.0 cannot be reconciled without deciding whether they are the same value. Preserve the literal token, and require ids as strings at the API boundary if you want them comparable.
- Reject duplicate keys rather than picking one. JSON permits them and parsers disagree, most keeping the last, so any choice you make ties the fingerprint to a parser detail that the code handling the request does not necessarily share.
Follow-up
- A client sends the same logical request with an extra field your API ignores. Same key, different fingerprint, so you return 422. Is that the right answer?
- Where does the fingerprint get computed relative to request decompression and the body-size limit?
Why do you want to join the engineering team at First horizon bank?
Why do you want to join the engineering team at First horizon bank?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
If you were tasked with optimizing a slow-performing database query, what steps would you take?
If you were tasked with optimizing a slow-performing database query, what steps would you take?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
Can you walk me through your previous projects and your specific role in them?
Can you walk me through your previous projects and your specific role in them?
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 are the most significant technical challenges you have faced in your career?
What are the most significant technical challenges you have faced in your career?
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?
Can you explain your approach to writing scalable and maintainable code?
Can you explain your approach to writing scalable and maintainable code?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
How do you ensure the security of the applications you develop?
How do you ensure the security of the applications you develop?
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 would you design a system to handle high-frequency transaction data?
How would you design a system to handle high-frequency transaction data?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
How do you approach debugging complex issues in a production environment?
How do you approach debugging complex issues in a production environment?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- 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?
Built from the rounds and topics First horizon bank candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the First horizon bank loop
- Write out the reported sequence: Screening Call, Technical Assessments, Onsite/Virtual Interview.
- 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.
02Work Take-home coding assessment
- Spend the session on Take-home coding assessment, which First horizon bank candidates report being tested on.
- Write one worked example in Take-home coding assessment and time yourself on it.
Deliverable: One timed worked example in Take-home coding assessment.
03Work Onsite follow-up interview
- Spend the session on Onsite follow-up interview, which First horizon bank candidates report being tested on.
- Write one worked example in Onsite follow-up interview and time yourself on it.
Deliverable: One timed worked example in Onsite follow-up interview.
04Work Communication skills (professionalism)
- Spend the session on Communication skills (professionalism), which First horizon bank candidates report being tested on.
- Write one worked example in Communication skills (professionalism) and time yourself on it.
Deliverable: One timed worked example in Communication skills (professionalism).
05Answer out loud: Experience and Background
- Answer aloud, timed: Can you walk me through your previous projects and your specific role in them?
- Answer aloud, timed: What are the most significant technical challenges you have faced in your career?
Deliverable: Spoken answers to 2 reported Experience and Background question(s), under time.
06Answer out loud: Technical and Domain Knowledge
- Answer aloud, timed: Can you explain your approach to writing scalable and maintainable code?
- Answer aloud, timed: How do you ensure the security of the applications you develop?
Deliverable: Spoken answers to 2 reported Technical and Domain Knowledge question(s), under time.
07Answer out loud: Problem-Solving and Logic
- Answer aloud, timed: How would you design a system to handle high-frequency transaction data?
- Answer aloud, timed: If you were tasked with optimizing a slow-performing database query, what steps would you take?
Deliverable: Spoken answers to 2 reported Problem-Solving and Logic 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.
How do you handle tight deadlines or shifting project requirements?
How do you handle tight deadlines or shifting project requirements?
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 the specific tech stack we use?
What is your experience with the specific tech stack we use?
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 you had to learn a new technology quickly to finish a project.
Describe a time you had to learn a new technology quickly to finish 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
How do you handle tight deadlines or shifting project requirements?
- 02
What is your experience with the specific tech stack we use?
- 03
Describe a time you had to learn a new technology quickly to finish a project.
How long does the entire process usually take?
The timeline varies, but from the initial HR screen to the final decision, it is designed to be efficient. Expect a structured flow once you pass the initial screening.
First horizon bank Software Engineer candidate reports ↗Should I expect a whiteboard coding session?
While formats vary, you should be prepared to discuss code, architecture, and logic. Whether it is a take-home assignment or a live session, the focus remains on your ability to solve problems logically.
First horizon bank Software Engineer candidate reports ↗What is the most important trait for success here?
Reliability and a methodical approach. We value engineers who think through the implications of their changes before implementing them, especially given the sensitive nature of our data.
First horizon bank Software Engineer candidate reports ↗How many rounds is the First horizon bank Software Engineer interview process?
Candidates report 3 stages: Screening Call, Technical Assessments, and Onsite/Virtual Interview. The interview process section above breaks down what each stage covers.
First horizon bank Software Engineer candidate reports ↗What topics come up in the First horizon bank Software Engineer interview?
First horizon bank Software Engineer interviews most often cover Take-home coding assessment, Onsite follow-up interview, Communication skills (professionalism), Technical screening (interview Q&A), and Coding assessment evaluation, based on topics extracted from real candidate reports.
First horizon bank 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.
- 01First horizon bank 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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