Avenue Code Software Engineer Interview Guide

The 60-second brief

As a Software Engineer at Avenue Code, you are stepping into a dynamic, high-impact role within a premier global IT consultancy. Avenue Code partners with Fortune 100 companies—including industry leaders like Apple, eBay, and Intuit—to deliver enterprise-grade digital transformations. In this role, you are not just writing code; you are acting as a strategic technical advisor and a core contributor to mission-critical products. Your work will directly influence the scalability, performance, and user experience of applications used by millions. Because Avenue Code operates on a consultancy model, you will often be embedded directly within a client's engineering organization. This requires a unique blend of deep technical expertise, adaptability, and exceptional communication skills to seamlessly integrate with diverse teams across different time zones.

This guide is scoped to a Software Engineer candidate at Avenue Code.

Focus areas

• Take-home programming assignments
• Technical interviewing
• Java

The Avenue Code interview process

Avenue Code candidates report 5 rounds over 4-6 weeks. The stages below are what candidates describe, not a published process.

Initial Screening

Screening by a Talent Acquisition partner to assess background, expectations, and English fluency.

What to demonstrate

• Screening by a Talent Acquisition partner to assess background, expectations, and English fluency
• Depth in Take-home programming assignments

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 Assessment

A timed HackerRank challenge or a multi-day take-home project focusing on algorithms and frameworks.

What to demonstrate

• A timed HackerRank challenge or a multi-day take-home project focusing on algorithms and frameworks
• Depth in Take-home programming assignments

How to prepare

• Answer aloud and timed: How do you write robust API integration tests, and what mocking libraries do you prefer?
• Answer aloud and timed: Can you explain the difference between REST and GraphQL, and when you would choose one over the other?

Technical Interview

Comprehensive technical interview with Avenue Code engineers, including live coding and architectural discussions.

What to demonstrate

• Comprehensive technical interview with Avenue Code engineers
• Including live coding and architectural discussions

How to prepare

• Answer aloud and timed: Describe the architecture of the most complex system you have worked on. What were the bottlenecks?
• Answer aloud and timed: Build a React component that fetches a list of articles from an API and sorts them based on user input. Include Jest/RTL tests.

Behavioral Interview

Interview with HR to assess cultural fit and soft skills.

What to demonstrate

• Interview with HR to assess cultural fit and soft skills
• Depth in Take-home programming assignments

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 interview above and write down what you would ask to confirm before it.

Client Interview

Meeting with the external team to ensure alignment on technical requirements and working styles.

What to demonstrate

• Meeting with the external team to ensure alignment on technical requirements and working styles
• Depth in Take-home programming assignments

How to prepare

• Answer aloud and timed: Refactor a given piece of legacy code to make it more modular and adhere to DRY principles.
• Answer aloud and timed: Tell me about a time you disagreed with a technical decision made by a senior engineer or architect. How did you handle it?

Where candidates lose points

Clarify Before Coding

During live coding or architecture rounds, do not jump straight into a solution. Spend the first few minutes asking clarifying questions to ensure you fully understand the constraints and edge cases.

Embrace the Consulting Mindset

Avenue Code wants engineers who can advise, not just execute. When discussing past projects, highlight instances where you proactively suggested improvements or guided stakeholders through technical trade-offs.

Do not underestimate the HR and Behavioral rounds

Interviewers are looking for red flags regarding ego, inflexibility, or poor communication. Treat the HR interview with the same level of preparation as the technical rounds.

Prepare Your Environment

If you are given a take-home test or HackerRank challenge, ensure you set aside uninterrupted time. Avenue Code values code quality highly, so include unit tests and clear documentation (like a well-written README) with any submitted code.

Questions & practice

Implement a custom EventEmitter class in Node.js that supports .on, .emit, and .off methods.

Medium · Practical Coding and Logic

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?

Solve a classic algorithmic problem (e.g., finding the longest substring without repeating characters) and opt

Medium · Practical Coding and Logic

Solve a classic algorithmic problem (e.g., finding the longest substring without repeating characters) and optimize its time complexity.

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?

Refactor a given piece of legacy code to make it more modular and adhere to DRY principles.

Medium · Practical Coding and Logic

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?

Explain why the owner filter ignores the listing index

Medium · composite index · query plans · sort elimination

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

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

Replace offset paging on the resource feed with keyset

Easy · keyset pagination · composite index · sort order

resource holds resource_id, tenant_id, owner_user_id, title, body_ref, version, status ('draft','active','archived','deleted'), created_at, updated_at, deleted_at, with an index on (tenant_id, status, updated_at DESC, resource_id DESC). The listing endpoint returns active resources for one tenant, newest update first, 50 per page, today with LIMIT 50 OFFSET n. Tenants reach page 400 and rows are created while they read. Write the keyset query, define what the cursor carries and how it is encoded, and say which part of the index each predicate uses. Assume PostgreSQL 16.

Approach

1. Name the two failures separately. OFFSET 20000 makes the server produce and discard 20,000 rows, so page cost grows with depth rather than with page size. Independently, any write that changes how many rows sort above the offset moves the window between two fetches, and the direction decides which anomaly you get: an insert lands at the head of updated_at DESC and pushes already-returned rows down past the boundary, so they are returned a second time; a delete above the offset, or a row whose updated_at is bumped above the cursor, pulls rows up and one is never returned at all. Nothing in the response reveals either.
2. Write the seek: WHERE tenant_id = $1 AND status = 'active' AND (updated_at, resource_id) < ($2, $3) ORDER BY updated_at DESC, resource_id DESC LIMIT 50. The row-value comparison is one index range rather than a disjunction, and both columns are NOT NULL, which is what makes that comparison well defined.
3. Map each predicate onto the index: tenant_id and status are equality on the leading columns, (updated_at, resource_id) is the range, and the ORDER BY matches the index order so no Sort node appears and the scan stops after 50 rows. The DESC in the definition only matters for mixed directions — a plain ascending btree on the same columns is read backwards for this query.
4. Put both sort columns in the cursor and nothing the client can tamper with into another tenant: base64 of (updated_at, resource_id), validated server-side, with tenant_id taken from the principal.

Follow-up

• The client asks for 'jump to page 400'. What do you offer instead, and what does the honest version cost?
• Sort order becomes user-selectable across four columns. How many indexes is that, and which would you refuse to add?

Explain the SOLID principles and provide an example of how you have applied them in a recent project.

Medium · Core Technology and Architecture

Approach

1. Fix the scope first: who calls this, how often, and what they do when it fails.
2. Name the read and write paths separately; they rarely have the same bottleneck.
3. Choose a partition key and say what query it makes expensive.
4. 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 write robust API integration tests, and what mocking libraries do you prefer?

Medium · Core Technology and Architecture

Approach

1. Say who the caller is and what they do when the call fails halfway.
2. Define the identity of a request so a retry cannot double-apply it.
3. Separate accepted, pending, failed and confirmed; they are different facts.
4. 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?

Can you explain the difference between REST and GraphQL, and when you would choose one over the other?

Medium · Core Technology and Architecture

Approach

1. Say who the caller is and what they do when the call fails halfway.
2. Define the identity of a request so a retry cannot double-apply it.
3. Separate accepted, pending, failed and confirmed; they are different facts.
4. 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?

Describe the architecture of the most complex system you have worked on. What were the bottlenecks?

Medium · Core Technology and Architecture

Approach

1. Fix the scope first: who calls this, how often, and what they do when it fails.
2. Name the read and write paths separately; they rarely have the same bottleneck.
3. Choose a partition key and say what query it makes expensive.
4. 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?

Build a React component that fetches a list of articles from an API and sorts them based on user input. Includ

Medium · Practical Coding and Logic

Build a React component that fetches a list of articles from an API and sorts them based on user input. Include Jest/RTL tests.

Approach

1. Say who the caller is and what they do when the call fails halfway.
2. Define the identity of a request so a retry cannot double-apply it.
3. Separate accepted, pending, failed and confirmed; they are different facts.
4. 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 debug a Spring Boot API in a production environment?

Medium · Core Technology and Architecture

Approach

1. Establish what changed and when, before forming any theory.
2. Pick a bisection that eliminates candidates whichever way it turns out.
3. Check the instrumentation before believing the symptom.
4. 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?

Suggested practice checklist

Built from the rounds and topics Avenue Code candidates report.

Day 1 — Map the Avenue Code loop

• Write out the reported sequence: Initial Screening, Technical Assessment, Technical Interview, Behavioral Interview, Client Interview.
• 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.

Day 2 — Work Take-home programming assignments

• Spend the session on Take-home programming assignments, which Avenue Code candidates report being tested on.
• Write one worked example in Take-home programming assignments and time yourself on it.

Deliverable: One timed worked example in Take-home programming assignments.

Day 3 — Work Technical interviewing

• Spend the session on Technical interviewing, which Avenue Code candidates report being tested on.
• Write one worked example in Technical interviewing and time yourself on it.

Deliverable: One timed worked example in Technical interviewing.

Day 4 — Work Java

• Spend the session on Java, which Avenue Code candidates report being tested on.
• Write one worked example in Java and time yourself on it.

Deliverable: One timed worked example in Java.

Day 5 — Answer out loud: Core Technology and Architecture

• Answer aloud, timed: How would you debug a Spring Boot API in a production environment?
• Answer aloud, timed: Explain the SOLID principles and provide an example of how you have applied them in a recent project.

Deliverable: Spoken answers to 2 reported Core Technology and Architecture question(s), under time.

Day 6 — Answer out loud: Practical Coding and Logic

• Answer aloud, timed: Build a React component that fetches a list of articles from an API and sorts them based on user input. Include Jest/RTL tests.
• Answer aloud, timed: Implement a custom EventEmitter class in Node.js that supports .on, .emit, and .off methods.

Deliverable: Spoken answers to 2 reported Practical Coding and Logic question(s), under time.

Day 7 — Answer out loud: Behavioral and Consulting Skills

• Answer aloud, timed: Tell me about a time you disagreed with a technical decision made by a senior engineer or architect. How did you handle it?
• Answer aloud, timed: Describe a situation where client requirements changed drastically midway through a sprint. How did you adapt?

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

Behavioural preparation

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

Tell me about a time you disagreed with a technical decision made by a senior engineer or architect. How did y

Medium · Behavioral and Consulting Skills

Tell me about a time you disagreed with a technical decision made by a senior engineer or architect. How did you handle it?

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 client requirements changed drastically midway through a sprint. How did you adapt?

Medium · Behavioral and Consulting Skills

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?

Walk me through your previous experiences. What was your specific impact on the team's success?

Medium · Behavioral and Consulting Skills

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 ensure code quality and maintainability when working under tight deadlines?

Medium · Behavioral and Consulting Skills

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?

Why do you want to work in a consultancy model rather than a traditional product company?

Medium · Behavioral and Consulting Skills

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?