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TELUS Digital AI Community Software Engineer Interview Guide

TELUS Digital AI Community Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

As a Software Engineer within the TELUS Digital AI Community, you are at the intersection of human intelligence and machine learning. You are responsible for building, scaling, and maintaining the robust platforms that power AI data annotation, model training, and complex data processing. Your work directly impacts how global enterprises refine their algorithms, making this a role that requires both rigorous technical discipline and a deep understanding of data-driven product development. You will collaborate with cross-functional teams, including data scientists, product managers, and global engineering squads, to solve high-stakes challenges. Whether you are optimizing cloud architecture, designing scalable APIs, or ensuring the integrity of massive datasets, your contributions enable the TELUS Digital AI Community to deliver high-quality, actionable intelligence.

This guide is scoped to a Software Engineer candidate at TELUS Digital AI Community.

Focus areas

  • Java
  • Spring Boot
  • Data Structures & Algorithms (DSA)

The TELUS Digital AI Community interview process

TELUS Digital AI Community candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Recruiter Screening

Initial contact with a recruiter to discuss your background and assess role fit.

What to demonstrate

  • Initial contact with a recruiter to discuss your background and assess role fit
  • Depth in Java

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

Deep-dive technical rounds to evaluate your technical skills and knowledge.

What to demonstrate

  • Deep-dive technical rounds to evaluate your technical skills and knowledge
  • Depth in Java

How to prepare

  • Answer aloud and timed: What are the core principles of OOP, and how do you implement them to ensure code maintainability?
  • Answer aloud and timed: Can you describe a time you had to debug a complex issue in a distributed system?

Live Coding

Interactive coding session where you demonstrate your coding skills in real-time.

What to demonstrate

  • Interactive coding session where you demonstrate your coding skills in real-time
  • Depth in Java

How to prepare

  • Answer aloud and timed: How do you manage memory and state in a high-concurrency Node.js or Java application?
  • Answer aloud and timed: Write a function to manipulate an array to find a specific pattern or perform a transformation.

Managerial Discussion

Final discussion focused on managerial or client-related aspects of the role.

What to demonstrate

  • Final discussion focused on managerial or client-related aspects of the role
  • Depth in Java

How to prepare

  • Answer aloud and timed: How would you implement a specific algorithm to solve a data processing bottleneck?
  • Answer aloud and timed: Can you walk us through your approach to fixing a bug in a provided code snippet?

Where candidates lose points

Structure your answers

Use the STAR method (Situation, Task, Action, Result) for behavioral questions to keep your responses focused and impactful.

Be clear about your experience

If you are asked about a technology you don't know, be honest. Pivot to explaining how you would learn it or how you’ve handled similar challenges in your current stack.

Engage with the interviewer

Treat the interview as a collaborative problem-solving session rather than a test. Ask clarifying questions about the project or the team's current challenges.

Review your resume

Be prepared to dive deep into every project you have listed. Interviewers will often base technical questions on the technologies you claim to know.

Questions & practice

How do you manage memory and state in a high-concurrency Node.js or Java application?

Medium · Technical and Domain Fundamentals

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. 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 manipulate an array to find a specific pattern or perform a transformation.

Medium · Coding and Problem-Solving

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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 would you implement a specific algorithm to solve a data processing bottleneck?

Medium · Coding and Problem-Solving

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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 us through your approach to fixing a bug in a provided code snippet?

Medium · Coding and Problem-Solving

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. 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 is your strategy for writing unit tests for asynchronous code?

Medium · Coding and Problem-Solving

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. 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 approach the trade-off between algorithm time complexity and memory usage?

Medium · Coding and Problem-Solving

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. 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 approach optimizing a database query that is performing poorly in a production environment?

Medium · Technical and Domain Fundamentals

Approach

  1. Name the grain you start from and join outward from it.
  2. Check whether any join is one-to-many before aggregating, or the sums inflate.
  3. Say which index the query would use, and what makes it unusable.
  4. 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?

Denormalise tenant onto revisions and backfill it live

Hard · denormalisation · online migration · backfill

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

  1. 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.
  2. 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.
  3. 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.
  4. 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?

Can you explain the fundamental differences between RESTful APIs and modern alternatives?

Medium · Technical and Domain Fundamentals

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. 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 the core principles of OOP, and how do you implement them to ensure code maintainability?

Medium · Technical and Domain Fundamentals

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

Every query on one table stalls for forty seconds mid-deploy

Medium · lock contention · ddl · migrations

During a release on PostgreSQL, every query touching resource times out for about 40 seconds and then recovers with no intervention. The release ran one migration, ALTER TABLE resource ADD COLUMN archived_reason TEXT, and the migration log shows it completing in 6 ms. Unrelated tables showed no change in error rate. Explain how a 6 ms statement caused a 40-second stall, give the ordered checks you would run on a live system to confirm it, and give the migration procedure that prevents a repeat.

Approach

  1. Separate the statement's duration from the lock's duration. ADD COLUMN with no default is a catalogue-only change and genuinely runs in milliseconds, but it requires ACCESS EXCLUSIVE, and it cannot acquire that until every transaction already touching the table has finished.
  2. Account for the queueing, which is the part that surprises people. A lock request that is waiting blocks later requests for conflicting modes behind it rather than letting them overtake, so one long-open transaction holds the DDL and the DDL holds all the traffic. The stall length is set by the longest open transaction, not by the size of the change.
  3. Confirm on a live system in this order: pg_stat_activity for that table ordered by xact_start, looking for the oldest transaction and specifically for state = idle in transaction; then pg_locks where granted = false to find the waiter; then join them on pid to name blocker and blocked. pg_blocking_pids() does that join for you and is the fastest single call.
  4. Prevent rather than merely time it better. Set lock_timeout to a second or two on the migration session so the DDL abandons the queue after a bounded wait and is retried, instead of holding it for as long as the oldest transaction lives. Be exact about what that buys: queries arriving during the wait still queue behind the pending ACCESS EXCLUSIVE request, so each attempt costs them up to one lock_timeout of added latency. The outage goes from 40 seconds to about one second per attempt, not to zero. Also run migrations away from deploy-time peaks, and put a statement timeout and an idle-in-transaction timeout on the analytics role that opens the long transactions.

Follow-up

  • The same release also wants NOT NULL on that column. What is the sequence that gets there without a long lock?
  • Your lock_timeout retry fails ten times in a row because the analytics transaction is always open. What do you change?

Suggested practice checklist

Built from the rounds and topics TELUS Digital AI Community candidates report.

Day 1 — Map the TELUS Digital AI Community loop

  • Write out the reported sequence: Recruiter Screening, Technical Assessments, Live Coding, Managerial 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 4 reported rounds, with the weakest marked.

Day 2 — Work Java

  • Spend the session on Java, which TELUS Digital AI Community candidates report being tested on.
  • Write one worked example in Java and time yourself on it.

Deliverable: One timed worked example in Java.

Day 3 — Work Spring Boot

  • Spend the session on Spring Boot, which TELUS Digital AI Community candidates report being tested on.
  • Write one worked example in Spring Boot and time yourself on it.

Deliverable: One timed worked example in Spring Boot.

Day 4 — Work Data Structures & Algorithms (DSA)

  • Spend the session on Data Structures & Algorithms (DSA), which TELUS Digital AI Community candidates report being tested on.
  • Write one worked example in Data Structures & Algorithms (DSA) and time yourself on it.

Deliverable: One timed worked example in Data Structures & Algorithms (DSA).

Day 5 — Answer out loud: Technical and Domain Fundamentals

  • Answer aloud, timed: Can you explain the fundamental differences between RESTful APIs and modern alternatives?
  • Answer aloud, timed: How do you approach optimizing a database query that is performing poorly in a production environment?

Deliverable: Spoken answers to 2 reported Technical and Domain Fundamentals question(s), under time.

Day 6 — Answer out loud: Coding and Problem-Solving

  • Answer aloud, timed: Write a function to manipulate an array to find a specific pattern or perform a transformation.
  • Answer aloud, timed: How would you implement a specific algorithm to solve a data processing bottleneck?

Deliverable: Spoken answers to 2 reported Coding and Problem-Solving question(s), under time.

Day 7 — Answer out loud: Behavioral and Leadership

  • Answer aloud, timed: Where do you see your technical career trajectory over the next five years?
  • Answer aloud, timed: Describe a situation where you had to mentor a junior team member or share technical knowledge.

Deliverable: Spoken answers to 2 reported Behavioral and Leadership question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

Can you describe a time you had to debug a complex issue in a distributed system?

Medium · Technical and Domain Fundamentals

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?

Where do you see your technical career trajectory over the next five years?

Medium · Behavioral and Leadership

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 mentor a junior team member or share technical knowledge.

Medium · Behavioral and Leadership

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 stakeholders regarding technical implementation?

Medium · Behavioral and Leadership

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 adapt to a sudden change in project requirements.

Medium · Behavioral and Leadership

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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 approach learning a new technology or stack when a project demands it?

Medium · Behavioral and Leadership

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. 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?