As a Software Engineer at Proforma, you occupy a pivotal role in driving the technological advancements that support our franchise operations and enhance our product offerings. This position is not merely about writing code; it involves architecting robust solutions that optimize business processes and improve user experiences. You will be engaged in developing features that directly impact how our franchises operate, ensuring they have the tools necessary to provide exceptional service to our clients. The Software Engineer role is critical to ensuring that Proforma remains competitive in a rapidly changing market. You will work on complex systems that handle large volumes of data and user interactions, contributing to projects that enhance our web and mobile applications. The work you do will not only influence the immediate functionality of our products but will also shape the strategic direction of our technology initiatives. In this role, you will collaborate closely with cross-functional teams, including product managers, designers, and other engineers, to deliver innovative solutions. You can expect a dynamic environment where your contributions are valued and where you have the opportunity to make a real difference.
Phone Screen
reportedInitial phone screen to assess candidate's background and fit for the role.
What to demonstrate
- Initial phone screen to assess candidate's background and fit for the role
- Depth in Software Engineering
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
reportedCandidates undergo technical evaluations to demonstrate their coding and problem-solving skills.
What to demonstrate
- Candidates undergo technical evaluations to demonstrate their coding and problem-solving skills
- Depth in Software Engineering
How to prepare
- Answer aloud and timed: Describe a situation where you implemented a new technology or process. What was the outcome?
- Answer aloud and timed: What are design patterns, and can you give examples of when to use them?
On-site/Virtual Interview
reportedFinal interview stage where candidates meet with various team members to assess both technical and interpersonal capabilities.
What to demonstrate
- Final interview stage where candidates meet with various team members to assess both technical and interpersonal capabilities
- Depth in Software Engineering
How to prepare
- Answer aloud and timed: How do you ensure code quality and manage technical debt in a project?
- Answer aloud and timed: Describe a time when you faced a significant challenge on a project. How did you handle it?
PracHub editorial advice for the preparation topics above.
Practice coding interviews
Use platforms like LeetCode or HackerRank to sharpen your coding skills and get accustomed to timed challenges.
Review system design principles
Understand the key concepts and be prepared to discuss them in relation to your past work.
Prepare for behavioral questions
Use the STAR method to structure your answers and highlight your experiences effectively.
Understand Proforma's products
Familiarize yourself with our offerings, as this will help you contextualize your answers during the interview.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
If you encountered a project with ambiguous requirements, how would you clarify them?
If you encountered a project with ambiguous requirements, how would you clarify them?
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
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?
Archive a resource graph without breaking live references or recursing
Resources reference other resources within a tenant; for the largest tenant the reference table holds up to 2,000,000 nodes and 8,000,000 edges. Archiving a resource must archive everything reachable from it that nothing outside the set still references, refuse when a live external referrer exists, and terminate when references form cycles, which they legitimately do. Produce the archive order and the refusal list, targeting O(V+E). Say what stops the traversal crossing a tenant boundary, and why recursion is the wrong control structure at this size.
Approach
- Load the subgraph with the tenant predicate on both endpoints of the edge, not only on the side you started from. Scoping the left table alone is the classic cross-tenant leak: one mis-entered edge then pulls another tenant's resources into the traversal and, worse, into the archive.
- Traverse iteratively with an explicit stack. A 2,000,000-node graph can hold a chain deep enough to exhaust a native stack in the low tens of thousands of frames, and that failure is a process crash rather than an error you can return.
- Treat cycles as data rather than corruption: compute strongly connected components with Tarjan in O(V+E) using its own explicit stack, then condense. The condensation is a DAG, so a topological order over it gives the archive order, and every member of a component archives in one transaction because no order within a cycle is valid.
- Decide refusals with reverse edges. A candidate is archivable only if every in-edge originates inside the candidate set, so build the transpose or count in-degrees restricted to the visited set, and emit each blocked resource with the id of the external referrer, which is the only part of the answer an operator can act on.
Follow-up
- The graph is read in one query and the archive writes a minute later. What can change in between, and how do you make the write safe?
- The candidate set is 400,000 resources. Is that one transaction, and if not, what does a half-finished archive look like to a reader?
How would you optimize a SQL query that is running slowly?
How would you optimize a SQL query that is running slowly?
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?
Hold a per-tenant active cap against concurrent creates
A tenant on the standard plan may hold at most 50 resources with status='active'. The create handler runs SELECT count(*) FROM resource WHERE tenant_id = $1 AND status = 'active', compares to 50, then inserts. Two creates arrive 3 ms apart on different instances and the tenant lands at 51. Name the anomaly, say whether PostgreSQL 16 READ COMMITTED or REPEATABLE READ prevents it and why, then give an implementation that holds the cap at READ COMMITTED with the exact statements. Finally, say what changes when the cap is 'at most one running export per tenant' on job_run.
Approach
- Name it: write skew. The two transactions read an overlapping set and write disjoint rows, so there is no row-level conflict for the engine to detect and each commit is individually legal.
- Rule out the levels precisely. READ COMMITTED takes a fresh snapshot per statement and takes no lock on the counted rows, so both see 49. PostgreSQL's REPEATABLE READ is snapshot isolation: it removes non-repeatable reads and phantoms within the snapshot but still admits write skew, because the anomaly is not a re-read of a changed row, it is a read of a set that a concurrent transaction invalidates. Only SERIALIZABLE closes it, by tracking the read dependency and aborting one transaction with SQLSTATE 40001 — a guarantee that exists only if the application re-runs the whole transaction from the read.
- Convert the set predicate into a single-row conflict: keep tenant.active_resource_count and run UPDATE tenant SET active_resource_count = active_resource_count + 1 WHERE tenant_id = $1 AND active_resource_count < 50 in the same transaction as the INSERT. Zero affected rows is the cap, returned as 409. The row lock serialises the decision at any isolation level, and contention is bounded to one tenant's row — which is also the fair-scheduling unit, unlike a global counter that would convoy every tenant behind one row.
- State the cost you just took on: a counter is a second source of truth that can drift, so every path that changes status must adjust it inside the same transaction, and a periodic reconciliation has to exist, with resource_revision as the authority for what the count should have been.
Follow-up
- A resource moves from archived back to active. Which statements change, and what breaks if the counter update and the status change land in different transactions?
- The cap becomes plan-dependent and a plan can change mid-month. Where does the number 50 live, and who reads it?
Explain the difference between an abstract class and an interface.
Explain the difference between an abstract class and an interface.
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe a situation where you implemented a new technology or process. What was the outcome?
Describe a situation where you implemented a new technology or process. What was the outcome?
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 design patterns, and can you give examples of when to use them?
What are design patterns, and can you give examples of when to use 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?
How do you ensure code quality and manage technical debt in a project?
How do you ensure code quality and manage technical debt in a project?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Given a specific problem (e.g., a user experiencing issues with a feature), how would you go about diagnosing
Given a specific problem (e.g., a user experiencing issues with a feature), how would you go about diagnosing and resolving it?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you approach designing a system to handle increasing user loads?
How would you approach designing a system to handle increasing user loads?
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?
Listing latency scales with page size, not with filters
The tenant listing endpoint reads resource filtered by tenant_id and status, ordered by updated_at DESC, and returns each row plus the owner's display name from app_user and the actor of that resource's latest resource_revision. p99 is 55 ms at 10 rows per page and 1.4 s at 200. Database telemetry shows 401 statements per request, each under 1 ms, and nothing in the slow-query log. Diagnose the cause and give the fix, stating the statement count per request and the p99 you expect afterwards.
Approach
- Read the counters before forming a theory. 401 statements for 200 rows is one driver query plus two per row, and sub-millisecond execution with an empty slow-query log rules out a bad plan. The time is round trips, which is why it is invisible in every per-query metric and scales with rows returned rather than with filter selectivity.
- Name the two per-row statements from their normalised text: a single-row app_user lookup by user_id, and a resource_revision lookup by resource_id ordered by version DESC LIMIT 1. Confirm by dropping those two response fields and watching the statement count fall to one. That locates the calls in the serialisation layer, not the repository.
- Check that the arithmetic accounts for the whole gap. Measure one round trip to the replica in isolation; 400 trips at roughly 3 ms of network plus 0.2 ms of execution is about 1.3 s on top of a 55 ms baseline, which matches. If the multiplication had fallen short, the N+1 would only be part of the story and you would keep looking.
- Batch both lookups. Collect owner_user_ids and resource_ids from the driver query, then issue WHERE tenant_id = $1 AND user_id = ANY($2) for the users, and PostgreSQL's SELECT DISTINCT ON (resource_id) ... WHERE resource_id = ANY($2) ORDER BY resource_id, version DESC for the latest revision, which the UNIQUE (resource_id, version) index serves directly. On an engine without DISTINCT ON, use a lateral join or a row_number window. Three statements per request at any page size.
Follow-up
- The page size is capped at 200 today. What breaks first if it is raised to 2,000, and is it still this bug?
- How do you stop the next N+1 from reaching production, given that no individual query is slow and the endpoint's tests pass?
Built from the rounds and topics Proforma candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Proforma loop
- Write out the reported sequence: Phone Screen, Technical Assessments, On-site/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 Software Engineering
- Spend the session on Software Engineering, which Proforma candidates report being tested on.
- Write one worked example in Software Engineering and time yourself on it.
Deliverable: One timed worked example in Software Engineering.
03Work Technical Site / Infrastructure Familiarization
- Spend the session on Technical Site / Infrastructure Familiarization, which Proforma candidates report being tested on.
- Write one worked example in Technical Site / Infrastructure Familiarization and time yourself on it.
Deliverable: One timed worked example in Technical Site / Infrastructure Familiarization.
04Work Interview Process Understanding
- Spend the session on Interview Process Understanding, which Proforma candidates report being tested on.
- Write one worked example in Interview Process Understanding and time yourself on it.
Deliverable: One timed worked example in Interview Process Understanding.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: Explain the difference between an abstract class and an interface.
- Answer aloud, timed: How would you optimize a SQL query that is running slowly?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time when you faced a significant challenge on a project. How did you handle it?
- Answer aloud, timed: How do you prioritize your tasks when working on multiple projects simultaneously?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
07Answer out loud: Problem-Solving / Case Studies
- Answer aloud, timed: Given a specific problem (e.g., a user experiencing issues with a feature), how would you go about diagnosing and resolving it?
- Answer aloud, timed: How would you approach designing a system to handle increasing user loads?
Deliverable: Spoken answers to 2 reported Problem-Solving / Case Studies 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.
Describe a time when you faced a significant challenge on a project. How did you handle it?
Describe a time when you faced a significant challenge on a project. How did you handle it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you prioritize your tasks when working on multiple projects simultaneously?
How do you prioritize your tasks when working on multiple projects simultaneously?
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 role do you typically take in group projects or team settings?
What role do you typically take in group projects or team settings?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Can you provide an example of how you’ve mentored a junior developer or team member?
Can you provide an example of how you’ve mentored a junior developer or team member?
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 conflict within a team?
How do you handle conflict within a team?
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
Describe a time when you faced a significant challenge on a project. How did you handle it?
- 02
How do you prioritize your tasks when working on multiple projects simultaneously?
- 03
What role do you typically take in group projects or team settings?
- 04
Can you provide an example of how you’ve mentored a junior developer or team member?
How difficult is the interview process?
The interview process is rigorous but fair. Candidates typically find that preparation in both technical and behavioral areas significantly increases their confidence and performance.
Proforma Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate a strong blend of technical proficiency, problem-solving skills, and cultural fit with Proforma, along with a willingness to learn and adapt.
Proforma Software Engineer candidate reports ↗What is the company culture like?
Proforma fosters a collaborative and innovative environment, where team members are encouraged to share ideas and take initiative.
Proforma Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The process can take anywhere from a few weeks to a couple of months, depending on the role and team schedules.
Proforma Software Engineer candidate reports ↗Are there remote work options available?
While Proforma supports hybrid work arrangements, specific policies may vary by team and project needs.
Proforma Software Engineer candidate reports ↗What topics does Proforma test in interviews?
Proforma interviews most often cover Account Executive (AE) sales role, Marketing Analytics, Project Management, Software Engineering, and Outside sales. The exact emphasis depends on the specific role you apply for.
Proforma 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.
- 01Proforma 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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