As a Software Engineer at Hays Technology, you serve as a pivotal bridge between technical talent and high-impact business solutions. Unlike roles within a single product company, this position often involves working within the Hays Technology ecosystem to place and support developers in diverse, dynamic client environments. You are not just writing code; you are solving real-world technical problems for businesses that rely on your expertise to scale their operations and maintain competitive advantages. The scope of this role is broad and highly dependent on the specific client engagement. You may find yourself involved in the full Software Development Life Cycle (SDLC)—from brainstorming and requirement definition to prototyping, coding, testing, and long-term maintenance. Success in this role requires a high degree of adaptability, as you must be able to pivot between different architectures, such as B2B vs. B2C systems, and maintain a professional, consultative approach when interacting with stakeholders. Working at means operating in a fast-paced environment where your ability to communicate complex technical concepts is as valuable as your coding proficiency. You will be evaluated not only on your technical depth but also on your professional maturity, your ability to align with client needs, and your capacity to thrive in. Hays Technology hybrid or remote working models
Initial Screening Call
reportedA call with a recruiter to verify background, technical focus, and salary expectations.
What to demonstrate
- A call with a recruiter to verify background, technical focus, and salary expectations
- Depth in Salary Expectations
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
reportedDeeper technical assessments or interviews with the specific client you are being considered for.
What to demonstrate
- Deeper technical assessments or interviews with the specific client you are being considered for
- Depth in Salary Expectations
How to prepare
- Answer aloud and timed: What are your previous projects and the types of companies you have worked for?
- Answer aloud and timed: Can you describe your academic and professional path?
Client-Facing Interviews
reportedInterviews with the client that may include multiple rounds and various evaluations.
What to demonstrate
- Interviews with the client that may include multiple rounds and various evaluations
- Depth in Salary Expectations
How to prepare
- Answer aloud and timed: Why should we hire you?
- Answer aloud and timed: What programming languages are you familiar with?
PracHub editorial advice for the preparation topics above.
Clarify the role early
Ask questions about the client environment and the specific team you will be working with.
Be prepared for salary discussions
Have a clear understanding of your current compensation and your requirements for a move.
Practice your narrative
Be ready to explain your career path and why you are looking for a change in a way that sounds motivated and professional.
Follow up
If you do not hear back within a week, it is perfectly acceptable to send a polite follow-up email to your recruiter.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
What programming languages are you familiar with?
What programming languages are you familiar with?
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?
Implement a linked list data structure.
Implement a linked list data structure.
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 explain the various stages of the software development life cycle?
Can you explain the various stages of the software development life cycle?
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?
Write the update path that detects a concurrent edit
resource carries version INT NOT NULL DEFAULT 1. resource_revision holds revision_id, resource_id, version, actor_user_id, change_kind, patch JSONB, request_id, created_at with UNIQUE (resource_id, version). outbox_event holds aggregate_type, aggregate_id, aggregate_version, event_type, payload, status. A PUT carries the version the client read. Write the exact statements for the single transaction that applies the edit, records the revision and enqueues 'resource.updated', and give the handler's branch on zero affected rows. Then say what PostgreSQL 16 does under READ COMMITTED when two of these updates hit one row at once.
Approach
- One transaction, three writes, no network call inside it: UPDATE resource SET title = $3, version = version + 1, updated_at = now() WHERE resource_id = $1 AND tenant_id = $4 AND version = $2; then INSERT the resource_revision row at version $2 + 1; then INSERT the outbox_event row at the same aggregate_version. The event goes to a table rather than a broker because no transaction spans both.
- Branch on the affected-row count before doing anything else. Zero has three causes — stale version, wrong tenant, row gone — so re-read once and map to 409 carrying the current version, or 404 for an id outside the caller's tenant, which also stops the endpoint confirming that another tenant's id exists.
- State the engine behaviour instead of assuming it. Under READ COMMITTED the second UPDATE blocks on the row lock, and when the first commits PostgreSQL re-evaluates the WHERE clause against the newly committed row, so the version predicate now fails and the statement reports zero rows. Under REPEATABLE READ the identical collision raises SQLSTATE 40001 instead, so the handler must fold both shapes into one conflict response.
- Keep UNIQUE (resource_id, version) even though the predicate already serialises writers. It is what makes a lost update unwritable if any other path ever reaches the revision table, and it converts a logic bug into 23505 rather than into a silently missing history row.
Follow-up
- A client sends the version it read ten minutes ago and the resource has moved three versions. What is in your 409 so it can resolve the conflict without a full re-fetch?
- Two editors, two disjoint fields, no overlap. Does your answer still refuse the second write, and should it?
Tell me a little about yourself.
Tell me a little about yourself.
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?
Why are you searching for a new job?
Why are you searching for a new job?
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 your previous projects and the types of companies you have worked for?
What are your previous projects and the types of companies you have worked for?
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 describe your academic and professional path?
Can you describe your academic and professional path?
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?
Why should we hire you?
Why should we hire you?
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 deal with B2B vs. B2C architectures?
How do you deal with B2B vs. B2C architectures?
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 Hays Technology candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Hays Technology loop
- Write out the reported sequence: Initial Screening Call, Technical Assessments, Client-Facing Interviews.
- 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 Salary Expectations
- Spend the session on Salary Expectations, which Hays Technology candidates report being tested on.
- Write one worked example in Salary Expectations and time yourself on it.
Deliverable: One timed worked example in Salary Expectations.
03Work Programming Fundamentals (Data Structures)
- Spend the session on Programming Fundamentals (Data Structures), which Hays Technology candidates report being tested on.
- Write one worked example in Programming Fundamentals (Data Structures) and time yourself on it.
Deliverable: One timed worked example in Programming Fundamentals (Data Structures).
04Work English Proficiency
- Spend the session on English Proficiency, which Hays Technology candidates report being tested on.
- Write one worked example in English Proficiency and time yourself on it.
Deliverable: One timed worked example in English Proficiency.
05Answer out loud: Professional Experience and Background
- Answer aloud, timed: Tell me a little about yourself.
- Answer aloud, timed: Why are you searching for a new job?
Deliverable: Spoken answers to 2 reported Professional Experience and Background question(s), under time.
06Answer out loud: Technical Skills and Problem Solving
- Answer aloud, timed: What programming languages are you familiar with?
- Answer aloud, timed: Implement a linked list data structure.
Deliverable: Spoken answers to 2 reported Technical Skills and Problem Solving question(s), under time.
07Answer out loud: Behavioral and Culture Alignment
- Answer aloud, timed: Do you like to work remotely? Why?
- Answer aloud, timed: Tell me three strengths and three faults you have at work.
Deliverable: Spoken answers to 2 reported Behavioral and Culture Alignment 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.
Do you like to work remotely? Why?
Do you like to work remotely? Why?
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 three strengths and three faults you have at work.
Tell me three strengths and three faults you have at work.
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 describe three characteristics that describe you?
Can you describe three characteristics that describe you?
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 working in an environment that requires English proficiency?
How do you handle working in an environment that requires English proficiency?
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
Do you like to work remotely? Why?
- 02
Tell me three strengths and three faults you have at work.
- 03
Can you describe three characteristics that describe you?
- 04
How do you handle working in an environment that requires English proficiency?
How long does the interview process usually take?
While it varies, many candidates report a quick and smooth process, often receiving feedback within a week. However, be prepared for a potential multi-step process if you are being put forward for a specific client.
Hays Technology Software Engineer candidate reports ↗What is the best way to prepare for the initial recruiter screen?
Be ready to discuss your past experience, your current role, and your salary expectations clearly. The recruiter is looking for a professional who can represent the company well to their clients.
Hays Technology Software Engineer candidate reports ↗Are technical assessments common?
Yes, especially for roles where you will be working directly on development tasks. You may be asked to solve coding problems or discuss architectural decisions related to your past projects.
Hays Technology Software Engineer candidate reports ↗Is there any specific advice for the "salary" question?
Be transparent and research your market value beforehand. Interviewers often ask this early to ensure alignment between your expectations and the client's budget. Always clarify the working hours and nature of the contract early in the process to ensure they align with your personal expectations and work-life balance goals.
Hays Technology Software Engineer candidate reports ↗What topics does Hays Technology test in interviews?
Hays Technology interviews most often cover Communication Skills, Stakeholder Management, Behavioral Interviewing, Interview communication skills, and Excel (advanced). The exact emphasis depends on the specific role you apply for.
Hays Technology 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.
- 01Hays Technology 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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