A Software Engineer at Wurl plays a critical role in shaping the future of Connected TV (CTV) and Free Ad-supported Streaming TV (FAST). The engineering team builds and scales the foundational infrastructure that powers global video distribution, real-time advertising insertion, and complex data analytics pipelines. Your work directly impacts millions of viewers worldwide, ensuring seamless, high-quality streaming experiences across top-tier platforms. As a Software Engineer, you will tackle challenges related to massive scale, high availability, and low latency. The systems you design and maintain must process billions of ad requests and deliver synchronized video streams with near-zero downtime. This requires a deep understanding of backend systems, cloud infrastructure, and modern frontend frameworks to create cohesive, end-to-end solutions. At Wurl, engineering is not just about writing code; it is about solving complex distribution and monetization problems in a rapidly evolving industry. You will collaborate closely with product managers, data scientists, and operations teams to translate business requirements into robust, maintainable software architectures.
Initial Recruiting Screen
reportedFirst point of contact to evaluate candidate's background and fit for the role.
What to demonstrate
- First point of contact to evaluate candidate's background and fit for the role
- Depth in Coding interviews (problem solving)
How to prepare
- Answer aloud and timed: Write a function to count duplicate characters in a given string.
- Answer aloud and timed: Implement a lookup mechanism utilizing a map or hash table to retrieve data with optimal time complexity.
Technical Assessment
reportedPractical coding round using your own integrated development environment (IDE).
What to demonstrate
- Practical coding round using your own integrated development environment (IDE)
- Depth in Coding interviews (problem solving)
How to prepare
- Answer aloud and timed: Given an array of integers, find the first non-repeating element.
- Answer aloud and timed: Write a program to reverse a string without using built-in reverse functions.
Deep-Dive Technical Sessions
reportedIn-depth technical interviews focusing on problem-solving and engineering principles.
What to demonstrate
- In-depth technical interviews focusing on problem-solving and engineering principles
- Depth in Coding interviews (problem solving)
How to prepare
- Answer aloud and timed: How do you design and implement a caching layer to optimize database read performance?
- Answer aloud and timed: Explain the key strategies you would use to scale a backend service to handle sudden traffic spikes.
Executive Conversations
reportedInterviews with members of the executive leadership team to assess cultural alignment.
What to demonstrate
- Interviews with members of the executive leadership team to assess cultural alignment
- Depth in Coding interviews (problem solving)
How to prepare
- Answer aloud and timed: Describe your experience with cloud platforms like AWS, particularly regarding database scaling and storage.
- Answer aloud and timed: Discuss the advantages and disadvantages of Model-View-Controller (MVC) architectures in modern web applications.
PracHub editorial advice for the preparation topics above.
Prepare your local environment
Since you will be using your own IDE, make sure you have a clean workspace open, a compiler or interpreter ready to run, and a screen-sharing setup that is free of distractions.
Be precise about your resume
Ensure you can speak in detail about every technology and project listed on your resume. Interviewers may drill down into specific technical decisions you made during past migrations or implementations.
Avoid over-complicating your coding solutions
Focus first on writing a working, brute-force solution, explain your approach to the interviewer, and then discuss how you can optimize it for time and space complexity.
Clarify requirements early
When presented with a coding or design problem, do not jump straight into writing code. Take a moment to ask clarifying questions, define the inputs and outputs, and establish any constraints.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a function to count duplicate characters in a given string.
Write a function to count duplicate characters in a given string.
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 lookup mechanism utilizing a map or hash table to retrieve data with optimal time complexity.
Implement a lookup mechanism utilizing a map or hash table to retrieve data with optimal time complexity.
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 the first non-repeating element.
Given an array of integers, find the first non-repeating element.
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?
Write a program to reverse a string without using built-in reverse functions.
Write a program to reverse a string without using built-in reverse functions.
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?
How do you design and implement a caching layer to optimize database read performance?
How do you design and implement a caching layer to optimize database read performance?
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 the key strategies you would use to scale a backend service to handle sudden traffic spikes.
Explain the key strategies you would use to scale a backend service to handle sudden traffic spikes.
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 the advantages and disadvantages of Model-View-Controller (MVC) architectures in modern web applicatio
Discuss the advantages and disadvantages of Model-View-Controller (MVC) architectures in modern web applications.
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?
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 Wurl candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Wurl loop
- Write out the reported sequence: Initial Recruiting Screen, Technical Assessment, Deep-Dive Technical Sessions, Executive Conversations.
- 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 Coding interviews (problem solving)
- Spend the session on Coding interviews (problem solving), which Wurl candidates report being tested on.
- Write one worked example in Coding interviews (problem solving) and time yourself on it.
Deliverable: One timed worked example in Coding interviews (problem solving).
03Work AWS (cloud infrastructure)
- Spend the session on AWS (cloud infrastructure), which Wurl candidates report being tested on.
- Write one worked example in AWS (cloud infrastructure) and time yourself on it.
Deliverable: One timed worked example in AWS (cloud infrastructure).
04Work Caching strategies
- Spend the session on Caching strategies, which Wurl candidates report being tested on.
- Write one worked example in Caching strategies and time yourself on it.
Deliverable: One timed worked example in Caching strategies.
05Answer out loud: Coding and Algorithmic Problem-Solving
- Answer aloud, timed: Write a function to count duplicate characters in a given string.
- Answer aloud, timed: Implement a lookup mechanism utilizing a map or hash table to retrieve data with optimal time complexity.
Deliverable: Spoken answers to 2 reported Coding and Algorithmic Problem-Solving question(s), under time.
06Answer out loud: System Architecture and Backend Principles
- Answer aloud, timed: How do you design and implement a caching layer to optimize database read performance?
- Answer aloud, timed: Explain the key strategies you would use to scale a backend service to handle sudden traffic spikes.
Deliverable: Spoken answers to 2 reported System Architecture and Backend Principles question(s), under time.
07Answer out loud: Behavioral and Experience-Based Questions
- Answer aloud, timed: Walk me through a complex migration project you led or contributed to, focusing on the technical challenges and outcomes.
- Answer aloud, timed: How do you handle project estimations, and what is your approach when a deadline is at risk of being missed?
Deliverable: Spoken answers to 2 reported Behavioral and Experience-Based Questions 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 your experience with cloud platforms like AWS, particularly regarding database scaling and storage.
Describe your experience with cloud platforms like AWS, particularly regarding database scaling and storage.
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?
Walk me through a complex migration project you led or contributed to, focusing on the technical challenges an
Walk me through a complex migration project you led or contributed to, focusing on the technical challenges and outcomes.
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 project estimations, and what is your approach when a deadline is at risk of being missed?
How do you handle project estimations, and what is your approach when a deadline is at risk of being missed?
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 situation where you had to work with a technology stack that you were not entirely familiar with.
Describe a situation where you had to work with a technology stack that you were not entirely familiar with.
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 technical disagreements within an engineering team?
How do you handle technical disagreements within an engineering 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 your experience with cloud platforms like AWS, particularly regarding database scaling and storage.
- 02
Walk me through a complex migration project you led or contributed to, focusing on the technical challenges and outcomes.
- 03
How do you handle project estimations, and what is your approach when a deadline is at risk of being missed?
- 04
Describe a situation where you had to work with a technology stack that you were not entirely familiar with.
What is the difficulty level of the coding interviews at Wurl?
The coding questions generally align with easy-to-medium difficulty levels. The focus is on practical problem-solving, string manipulation, and basic data structures rather than complex, abstract algorithmic puzzles.
Wurl Software Engineer candidate reports ↗Can I use my own development environment during the technical rounds?
Yes. Unlike many companies that require you to write code in a restrictive browser-based platform, Wurl typically allows you to use your own IDE. You should ensure your preferred environment is configured and ready to share via video call.
Wurl Software Engineer candidate reports ↗What is the engineering culture like regarding deadlines and estimations?
Wurl maintains a strong delivery-focused culture. While engineers are responsible for providing their own project estimates, there is a high expectation of accountability to meet those commitments, which can sometimes result in fast-paced delivery cycles.
Wurl Software Engineer candidate reports ↗How involved is the executive leadership in the hiring process?
The final stages of the process frequently include a conversation with a senior executive, such as the CTO or CEO. This round is generally a high-level meet-and-greet focused on strategic alignment, culture fit, and your future growth within the company.
Wurl Software Engineer candidate reports ↗What topics does Wurl test in interviews?
Wurl interviews most often cover Stakeholder Management, Coding interviews (problem solving), Full-Stack Engineering, Data Engineering (Role Fundamentals), and AWS (cloud infrastructure). The exact emphasis depends on the specific role you apply for.
Wurl Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
Official role evidence, timestamped platform data and clearly labeled preparation advice.
- 01Wurl Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
candidate · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
platform · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
platform · Accessed 2026-09-22
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