Taboola hires Software Engineers; this guide collects what candidates report about the process.
Initial Screening
reportedAlign on technical expectations through a preliminary discussion.
What to demonstrate
- Align on technical expectations through a preliminary discussion
- Depth in Data Structures
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 Interviews
reportedParticipate in a series of deep-dive technical interviews covering algorithmic challenges.
What to demonstrate
- Participate in a series of deep-dive technical interviews covering algorithmic challenges
- Depth in Data Structures
How to prepare
- Answer aloud and timed: Describe how you would implement a thread-safe cache or a concurrent hash map.
- Answer aloud and timed: Explain the difference between asynchronous functions and synchronous execution in your preferred language.
Home Assignments
reportedComplete assigned tasks or projects to demonstrate technical skills.
What to demonstrate
- Complete assigned tasks or projects to demonstrate technical skills
- Depth in Data Structures
How to prepare
- Answer aloud and timed: How do you calculate the time complexity of a recursive algorithm?
- Answer aloud and timed: How would you design a recommendation widget similar to the one Taboola uses on news sites?
Project Discussions
reportedDiscuss your past projects and experiences in detail.
What to demonstrate
- Discuss your past projects and experiences in detail
- Depth in Data Structures
How to prepare
- Answer aloud and timed: How do you ensure high availability and low latency in a distributed system?
- Answer aloud and timed: Walk me through a challenging bug you encountered in a production environment and how you diagnosed it.
PracHub editorial advice for the preparation topics above.
Clarify Requirements
Always ask clarifying questions before jumping into a coding problem. It demonstrates that you think before acting.
Test Your Code
Always consider edge cases and explain how your code handles them before the interviewer asks.
Stay Professional
Even if you feel the interview is not going well, maintain a collaborative and positive attitude.
Prepare for "Why Taboola?
Have a clear, articulated reason for why you want to work at this company specifically.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Explain the pros and cons of using an Array versus an ArrayList.
Explain the pros and cons of using an Array versus an ArrayList.
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 string, how would you find the first non-repeating character in $O(n)$ time?
Given a string, how would you find the first non-repeating character in $O(n)$ time?
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?
Describe how you would implement a thread-safe cache or a concurrent hash map.
Describe how you would implement a thread-safe cache or a concurrent hash map.
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?
Explain the difference between asynchronous functions and synchronous execution in your preferred language.
Explain the difference between asynchronous functions and synchronous execution in your preferred language.
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?
How do you calculate the time complexity of a recursive algorithm?
How do you calculate the time complexity of a recursive 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 do you approach optimizing a database query that is performing poorly under load?
How do you approach optimizing a database query that is performing poorly under load?
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?
Explain why the owner filter ignores the listing index
The only index on resource is (tenant_id, status, updated_at DESC, resource_id DESC). A new endpoint returns one user's resources across all statuses, newest created first: WHERE tenant_id = $1 AND owner_user_id = $2 ORDER BY created_at DESC LIMIT 20. On a tenant with 2M rows it takes 900 ms and EXPLAIN shows a sort above a large scan. Explain precisely why the existing index cannot serve it, give the index that can, and state which of these the new index still will not help: owner_user_id alone across tenants; the same query ordered by updated_at. PostgreSQL 16.
Approach
- Separate the two jobs an index does. For filtering, a composite btree is seekable only on a left prefix, so with no predicate on status the scan can at best range over tenant_id and test owner_user_id per row; PostgreSQL 16 has no btree skip scan to jump the unconstrained column.
- For ordering, the index is sorted by (status, updated_at) within a tenant and not by created_at, so the LIMIT cannot stop early: every matching row is read and then sorted. That is the 'Sort Method: top-N heapsort' line, and it is why the plan reads 2M rows to answer with 20.
- Derive the replacement from the access path — equality, equality, then the ordering column: CREATE INDEX CONCURRENTLY ON resource (tenant_id, owner_user_id, created_at DESC). The scan seeks to the (tenant, owner) range and walks 20 entries in order, so the Sort node disappears along with the row-read.
- Treat INCLUDE (title, status) as conditional, not free. An index-only scan still visits the heap for any row whose page is not marked all-visible, so on a table taking 1.2k writes/second the win depends on autovacuum keeping the visibility map current, and the wider index costs more on every insert.
Follow-up
- 90% of rows are status='active'. Would a partial index WHERE status = 'active' change your answer, and for which of the three queries?
- A dashboard runs this for 40 owners in one page load. What changes about the design?
How would you design a recommendation widget similar to the one Taboola uses on news sites?
How would you design a recommendation widget similar to the one Taboola uses on news sites?
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 high availability and low latency in a distributed system?
How do you ensure high availability and low latency in a distributed 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?
Walk me through a challenging bug you encountered in a production environment and how you diagnosed it.
Walk me through a challenging bug you encountered in a production environment and how you diagnosed it.
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?
If a service is experiencing a spike in latency, what steps do you take to identify the root cause?
If a service is experiencing a spike in latency, what steps do you take to identify the root cause?
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 Taboola candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Taboola loop
- Write out the reported sequence: Initial Screening, Technical Interviews, Home Assignments, Project Discussions.
- 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 4 reported rounds, with the weakest marked.
02Work Data Structures
- Spend the session on Data Structures, which Taboola candidates report being tested on.
- Write one worked example in Data Structures and time yourself on it.
Deliverable: One timed worked example in Data Structures.
03Work Algorithms
- Spend the session on Algorithms, which Taboola candidates report being tested on.
- Write one worked example in Algorithms and time yourself on it.
Deliverable: One timed worked example in Algorithms.
04Work Time Complexity Analysis
- Spend the session on Time Complexity Analysis, which Taboola candidates report being tested on.
- Write one worked example in Time Complexity Analysis and time yourself on it.
Deliverable: One timed worked example in Time Complexity Analysis.
05Answer out loud: Technical & Algorithmic Proficiency
- Answer aloud, timed: Explain the pros and cons of using an Array versus an ArrayList.
- Answer aloud, timed: Given a string, how would you find the first non-repeating character in $O(n)$ time?
Deliverable: Spoken answers to 2 reported Technical & Algorithmic Proficiency question(s), under time.
06Answer out loud: System Design & Problem Solving
- Answer aloud, timed: How would you design a recommendation widget similar to the one Taboola uses on news sites?
- Answer aloud, timed: How do you ensure high availability and low latency in a distributed system?
Deliverable: Spoken answers to 2 reported System Design & Problem Solving question(s), under time.
07Answer out loud: Behavioral & Experience
- Answer aloud, timed: Tell me about a project where you had to make a significant technical trade-off.
- Answer aloud, timed: How do you handle disagreements with team members regarding architectural decisions?
Deliverable: Spoken answers to 2 reported Behavioral & Experience 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.
Tell me about a project where you had to make a significant technical trade-off.
Tell me about a project where you had to make a significant technical trade-off.
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 disagreements with team members regarding architectural decisions?
How do you handle disagreements with team members regarding architectural decisions?
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?
Why are you interested in working at Taboola specifically?
Why are you interested in working at Taboola specifically?
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 stack on the fly to meet a project deadline.
Describe a time you had to learn a new technology stack on the fly 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
Tell me about a project where you had to make a significant technical trade-off.
- 02
How do you handle disagreements with team members regarding architectural decisions?
- 03
Why are you interested in working at Taboola specifically?
- 04
Describe a time you had to learn a new technology stack on the fly to meet a project deadline.
How much time should I allocate for the home assignment?
While some assignments are designed to take a few hours, candidates often spend 1–3 days to ensure high code quality. Focus on writing clean, generic, and well-tested code rather than just meeting the basic requirements.
Taboola Software Engineer candidate reports ↗Is the interview process difficult?
Most candidates describe the difficulty as average to high. The technical rounds are rigorous, and the process can be long, so prepare for a marathon rather than a sprint.
Taboola Software Engineer candidate reports ↗What is the best way to stand out?
Be prepared to discuss your past projects in extreme detail. Showing that you understand the trade-offs you made—and why you made them—is often what separates a good candidate from a great one.
Taboola Software Engineer candidate reports ↗What topics does Taboola test in interviews?
Taboola interviews most often cover SQL, JavaScript, Stakeholder Management, HTML, and Problem Solving. The exact emphasis depends on the specific role you apply for.
Taboola 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.
- 01Taboola 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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