As a Software Engineer at Hiya, you play a crucial role in developing innovative solutions that enhance communication experiences for users globally. Your work directly impacts products that help identify and block unwanted calls, providing a safer and more user-friendly digital environment. At Hiya, you will be involved in tackling complex problems that require not only technical expertise but also creativity and strategic thinking. This position is critical because it bridges the gap between cutting-edge technology and real-world applications, impacting millions of users. You will collaborate closely with cross-functional teams, contributing to a culture of innovation and quality. The challenges you face will vary from optimizing algorithms to improving system architectures, making your role dynamic and essential to the company’s mission. Candidates can expect to work on meaningful projects, utilizing modern technology stacks while also engaging in a culture that values continuous learning and improvement. This position offers the opportunity to contribute to a rapidly evolving tech landscape, where your contributions will have a tangible effect on product performance and user satisfaction.
Phone Screening
reportedHR will gauge your alignment with the role during an initial phone call.
What to demonstrate
- HR will gauge your alignment with the role during an initial phone call
- Depth in Algorithm Design
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.
Coding Assessment
reportedCandidates will solve algorithmic problems online, typically through platforms like HackerRank.
What to demonstrate
- Candidates will solve algorithmic problems online, typically through platforms like HackerRank
- Depth in Algorithm Design
How to prepare
- Answer aloud and timed: How does garbage collection work in Java?
- Answer aloud and timed: Describe the principles of RESTful API design.
Technical Interviews
reportedMultiple rounds of interviews with engineers and project managers focusing on technical skills.
What to demonstrate
- Multiple rounds of interviews with engineers and project managers focusing on technical skills
- Depth in Algorithm Design
How to prepare
- Answer aloud and timed: What are the key differences between SQL and NoSQL databases?
- Answer aloud and timed: Write a function to reverse a linked list.
Behavioral Interviews
reportedInterviews assessing cultural fit and collaboration skills.
What to demonstrate
- Interviews assessing cultural fit and collaboration skills
- Depth in Algorithm Design
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral interviews above and write down what you would ask to confirm before it.
System Design Discussion
reportedPossible discussion for more senior roles focusing on system design and architecture.
What to demonstrate
- Possible discussion for more senior roles focusing on system design and architecture
- Depth in Algorithm Design
How to prepare
- Answer aloud and timed: Solve a problem using dynamic programming, such as the Knapsack problem.
- Answer aloud and timed: Create a function that performs a depth-first search on a binary tree.
PracHub editorial advice for the preparation topics above.
Understand Hiya’s mission
Familiarize yourself with Hiya’s products and how they improve user experiences. This knowledge will help you contextualize your answers during interviews.
Practice coding under time constraints
As many assessments will be timed, practice solving coding problems efficiently to build confidence and speed.
Be ready for scenario-based questions
Prepare to discuss past projects and how you approached challenges, as this will demonstrate your problem-solving abilities and collaboration skills.
Prepare questions for your interviewers
Engaging your interviewers with thoughtful questions can show your genuine interest in the role and the company.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Explain how you would implement a binary search algorithm.
Explain how you would implement a binary search algorithm.
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?
How does garbage collection work in Java?
How does garbage collection work in Java?
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?
Write a function to reverse a linked list.
Write a function to reverse a linked list.
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 an array of integers, find two numbers such that they add up to a specific target.
Given an array of integers, find two numbers such that they add up to a specific target.
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 function to check if a string is a palindrome.
Implement a function to check if a string is a palindrome.
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?
Solve a problem using dynamic programming, such as the Knapsack problem.
Solve a problem using dynamic programming, such as the Knapsack problem.
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?
Create a function that performs a depth-first search on a binary tree.
Create a function that performs a depth-first search on a binary tree.
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?
What are the key differences between SQL and NoSQL databases?
What are the key differences between SQL and NoSQL databases?
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?
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?
What is the difference between a stack and a queue?
What is the difference between a stack and a queue?
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 the principles of RESTful API design.
Describe the principles of RESTful API design.
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?
How would you design a URL shortening service?
How would you design a URL shortening service?
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?
Discuss how you would architect a call blocking system.
Discuss how you would architect a call blocking 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?
Explain how you would handle data consistency in a distributed database.
Explain how you would handle data consistency in a distributed database.
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?
Describe your approach to designing a messaging application.
Describe your approach to designing a messaging application.
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?
What considerations would you take into account when building an API for a mobile app?
What considerations would you take into account when building an API for a mobile app?
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?
One customer endpoint stalls deliveries to every other destination
The egress service delivers about 1.5k webhooks/second across 40,000 destinations, with a per-destination concurrency cap of 4 and a 10-second connect-plus-read timeout. Throughput falls to 300/second, queue depth climbs, and p99 delivery latency for unaffected destinations goes from 200 ms to minutes, while the error rate barely moves. One tenant holds 900 destination rows whose URLs share a hostname that now answers in 9.5 seconds. Explain the mechanism with the arithmetic, then give the containment in the order you would apply it.
Approach
- Look at saturation before errors. A flat error rate with collapsing throughput says nothing is failing, things are waiting, so the first signal to pull is in-flight request count or pool wait time rather than the error counter. This is the distinction that decides the whole investigation.
- Group in-flight work by resolved host, not by destination id. The cap is keyed per destination row, so 900 rows sharing one hostname buy 3,600 concurrent slots against a single host, each held for 9.5 seconds. The bulkhead was never a bulkhead for that host, and grouping by the wrong dimension is why the dashboard looked healthy.
- Do the arithmetic in both directions. Required concurrency is arrival rate times latency, so 1.5k/second at 200 ms needs about 300 in flight, which is entirely consumed by 3,600 slow slots; conversely whatever concurrency is left sustains rate equals concurrency divided by 9.5 seconds, which is the 300/second you are seeing. Matching both numbers is what promotes this from a plausible story to the mechanism.
- Explain why the circuit breaker never helped. It opens on consecutive failures, and a 9.5-second response inside a 10-second timeout is a success. Slow is not failing, so an error-rate breaker cannot see this; you need a slow-call ratio, a deadline propagated from the caller's remaining budget, or a concurrency limiter.
Follow-up
- The host recovers to 80 ms. How long does the queue take to drain, and what does the drain do to the recovered host?
- Where should the 10-second timeout number actually come from?
Built from the rounds and topics Hiya candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Hiya loop
- Write out the reported sequence: Phone Screening, Coding Assessment, Technical Interviews, Behavioral Interviews, System Design Discussion.
- 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 5 reported rounds, with the weakest marked.
02Work Algorithm Design
- Spend the session on Algorithm Design, which Hiya candidates report being tested on.
- Write one worked example in Algorithm Design and time yourself on it.
Deliverable: One timed worked example in Algorithm Design.
03Work Code Correctness & Edge Cases
- Spend the session on Code Correctness & Edge Cases, which Hiya candidates report being tested on.
- Write one worked example in Code Correctness & Edge Cases and time yourself on it.
Deliverable: One timed worked example in Code Correctness & Edge Cases.
04Work Problem Solving
- Spend the session on Problem Solving, which Hiya candidates report being tested on.
- Write one worked example in Problem Solving and time yourself on it.
Deliverable: One timed worked example in Problem Solving.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What is the difference between a stack and a queue?
- Answer aloud, timed: Explain how you would implement a binary search algorithm.
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Coding / Algorithms
- Answer aloud, timed: Write a function to reverse a linked list.
- Answer aloud, timed: Given an array of integers, find two numbers such that they add up to a specific target.
Deliverable: Spoken answers to 2 reported Coding / Algorithms question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a challenging project you worked on and how you overcame obstacles.
- Answer aloud, timed: How do you prioritize tasks when working on multiple projects?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership 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 challenging project you worked on and how you overcame obstacles.
Describe a challenging project you worked on and how you overcame obstacles.
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 working on multiple projects?
How do you prioritize tasks when working on multiple projects?
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 received constructive criticism. How did you respond?
Tell me about a time you received constructive criticism. How did you respond?
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 do you value most in a team environment?
What do you value most in a team environment?
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 challenging project you worked on and how you overcame obstacles.
- 02
How do you prioritize tasks when working on multiple projects?
- 03
Tell me about a time you received constructive criticism. How did you respond?
- 04
What do you value most in a team environment?
How difficult are the interviews, and how much preparation time is typical?
Interviews at Hiya are moderately challenging, focusing on both technical and behavioral aspects. Candidates typically spend several weeks preparing, particularly for coding assessments and system design discussions.
Hiya Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate a balanced combination of technical skills, problem-solving abilities, and strong interpersonal communication. They show enthusiasm for the role and align closely with Hiya's values.
Hiya Software Engineer candidate reports ↗Can you describe the culture and working style at Hiya?
Hiya promotes a collaborative and innovative culture where team members are encouraged to share ideas and feedback. A strong emphasis is placed on user-centric design and continuous improvement.
Hiya Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The interview process usually takes 3-4 weeks, depending on scheduling and the number of candidates. Candidates should be prepared for multiple rounds of interviews during this period.
Hiya Software Engineer candidate reports ↗Are there remote work or hybrid expectations?
Hiya offers flexible work arrangements, with options for remote work depending on the team's needs and the candidate's location. Candidates should clarify preferences during the interview process.
Hiya Software Engineer candidate reports ↗What topics does Hiya test in interviews?
Hiya interviews most often cover Problem Solving, Stakeholder Communication, Requirements Gathering, Time Management, and Financial Analysis. The exact emphasis depends on the specific role you apply for.
Hiya 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.
- 01Hiya 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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