A Software Engineer at SIRCLO plays a pivotal role in shaping the e-commerce infrastructure that empowers businesses across Southeast Asia. You are not just writing code; you are building scalable, high-impact systems that handle complex data workflows and user interactions. Whether you are working on core platform features or integrating cutting-edge AI solutions, your contributions directly affect how merchants operate and grow in a digital-first economy. The environment at SIRCLO is one of high ownership and technical rigor. You will be expected to treat programming languages as tools and prioritize architectural integrity, maintainability, and production readiness over manual code volume. Whether you are designing data architectures or auditing AI-generated codebases, your work will be defined by your ability to translate business needs into robust, efficient technical designs. ##### Tip SIRCLO values engineers who possess a generalist mindset. Expect to be evaluated on your ability to own features end-to-end, from local development and testing to CI/CD and production deployment.
Initial Screening
reportedConducted by HR to align on your experience and career aspirations.
What to demonstrate
- Conducted by HR to align on your experience and career aspirations
- Depth in AI-Assisted Coding / Native AI Development Workflow
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 Assessment
reportedIncludes a take-home project or a live coding session.
What to demonstrate
- Includes a take-home project or a live coding session
- Depth in AI-Assisted Coding / Native AI Development Workflow
How to prepare
- Answer aloud and timed: What is your process for debugging complex systems when traditional methods fail?
- Answer aloud and timed: How do you evaluate whether to use a specific library versus a framework in a new project?
User-Focused Interview
reportedInterview with a hiring manager or senior engineering leader.
What to demonstrate
- Interview with a hiring manager or senior engineering leader
- Depth in AI-Assisted Coding / Native AI Development Workflow
How to prepare
- Answer aloud and timed: How do you ensure the maintainability and readability of code that you have generated or modified using AI tools?
- Answer aloud and timed: Describe your approach to the "Ship problem" or "Cart problem" using Object-Oriented Programming principles.
PracHub editorial advice for the preparation topics above.
Prioritize Simplicity
If you are in doubt during a coding test, choose the most readable and maintainable solution.
Prepare Your "Why
Be ready to explain why you chose a specific library, database, or architecture over alternatives.
Communicate Your Process
During live coding, talk through your thought process. Interviewers want to see how you approach ambiguity.
Review Your Past Work
Be ready to discuss the technical challenges you faced in your previous roles and how you grew from them.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Describe your approach to the "Ship problem" or "Cart problem" using Object-Oriented Programming principles.
Describe your approach to the "Ship problem" or "Cart problem" using Object-Oriented Programming principles.
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?
Given a set of requirements, how do you break down a complex task into smaller, testable units?
Given a set of requirements, how do you break down a complex task into smaller, testable units?
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?
Can you walk through your process of optimizing a function that is underperforming in production?
Can you walk through your process of optimizing a function that is underperforming in production?
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?
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 do you approach solving a technical problem to ensure the solution is both simple and effective?
How do you approach solving a technical problem to ensure the solution is both simple and effective?
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 how you would design a scalable data architecture for a high-traffic system?
Can you explain how you would design a scalable data architecture for a high-traffic system?
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 evaluate whether to use a specific library versus a framework in a new project?
How do you evaluate whether to use a specific library versus a framework in a new 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?
How do you ensure the maintainability and readability of code that you have generated or modified using AI too
How do you ensure the maintainability and readability of code that you have generated or modified using AI tools?
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 is your process for debugging complex systems when traditional methods fail?
What is your process for debugging complex systems when traditional methods fail?
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 SIRCLO candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the SIRCLO loop
- Write out the reported sequence: Initial Screening, Technical Assessment, User-Focused 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 AI-Assisted Coding / Native AI Development Workflow
- Spend the session on AI-Assisted Coding / Native AI Development Workflow, which SIRCLO candidates report being tested on.
- Write one worked example in AI-Assisted Coding / Native AI Development Workflow and time yourself on it.
Deliverable: One timed worked example in AI-Assisted Coding / Native AI Development Workflow.
03Work Problem Solving (Logical Thinking)
- Spend the session on Problem Solving (Logical Thinking), which SIRCLO candidates report being tested on.
- Write one worked example in Problem Solving (Logical Thinking) and time yourself on it.
Deliverable: One timed worked example in Problem Solving (Logical Thinking).
04Work High Ownership / End-to-End Ownership
- Spend the session on High Ownership / End-to-End Ownership, which SIRCLO candidates report being tested on.
- Write one worked example in High Ownership / End-to-End Ownership and time yourself on it.
Deliverable: One timed worked example in High Ownership / End-to-End Ownership.
05Answer out loud: Technical and Domain Knowledge
- Answer aloud, timed: How do you approach solving a technical problem to ensure the solution is both simple and effective?
- Answer aloud, timed: Can you explain how you would design a scalable data architecture for a high-traffic system?
Deliverable: Spoken answers to 2 reported Technical and Domain Knowledge question(s), under time.
06Answer out loud: Problem-Solving and Coding
- Answer aloud, timed: Describe your approach to the "Ship problem" or "Cart problem" using Object-Oriented Programming principles.
- Answer aloud, timed: Given a set of requirements, how do you break down a complex task into smaller, testable units?
Deliverable: Spoken answers to 2 reported Problem-Solving and Coding question(s), under time.
07Answer out loud: Behavioral and Cultural Fit
- Answer aloud, timed: Tell us about a time you had to take full ownership of a feature from development to deployment.
- Answer aloud, timed: How do you handle situations where you disagree with a technical decision made by a team member?
Deliverable: Spoken answers to 2 reported Behavioral and Cultural Fit 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 edge cases when building data structures for e-commerce workflows?
How do you handle edge cases when building data structures for e-commerce workflows?
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 us about a time you had to take full ownership of a feature from development to deployment.
Tell us about a time you had to take full ownership of a feature from development to deployment.
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 situations where you disagree with a technical decision made by a team member?
How do you handle situations where you disagree with a technical decision made by a 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?
Describe a time you had to learn a new tool or language quickly to meet a project deadline.
Describe a time you had to learn a new tool or language quickly to meet a project deadline.
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 edge cases when building data structures for e-commerce workflows?
- 02
Tell us about a time you had to take full ownership of a feature from development to deployment.
- 03
How do you handle situations where you disagree with a technical decision made by a team member?
- 04
Describe a time you had to learn a new tool or language quickly to meet a project deadline.
How difficult are the technical interviews?
The difficulty is generally considered average. The focus is on practical problem-solving rather than "gotcha" questions, so focus on writing clean, simple code rather than memorizing complex algorithms.
SIRCLO Software Engineer candidate reports ↗How much preparation time should I allocate?
While it depends on your current experience, 1–2 weeks of focused review on your core language and system design principles is typically sufficient.
SIRCLO Software Engineer candidate reports ↗Is the process remote-friendly?
Most interviews are conducted via video conferencing, allowing for a seamless experience regardless of your location.
SIRCLO Software Engineer candidate reports ↗What is the best way to stand out?
Demonstrate high ownership. When discussing past projects, clearly explain the challenges you faced and the specific, simple actions you took to resolve them.
SIRCLO Software Engineer candidate reports ↗What topics does SIRCLO test in interviews?
SIRCLO interviews most often cover AI-Assisted Coding / Native AI Development Workflow, Sales fundamentals, Problem Solving (Logical Thinking), High Ownership / End-to-End Ownership, and Account executive / key account management concepts. The exact emphasis depends on the specific role you apply for.
SIRCLO 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.
- 01SIRCLO 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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