cswork / libraryOpen practice workspace

Interview guides · Next Ventures

Next Ventures Software Engineer Interview Guide

Next Ventures Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

A Software Engineer at Next Ventures is at the forefront of building the next generation of financial technology, trading systems, and brokerage infrastructure. The engineering team is responsible for designing, scaling, and maintaining high-performance platforms that handle complex transaction rules, risk assessment, and real-time market data. Because Next Ventures operates in a highly competitive, fast-paced domain, engineers do not merely write code; they build highly resilient, low-latency solutions that directly impact global traders and partners. What makes this role uniquely compelling is the company's aggressive shift toward AI-Native and AI-Accelerated Development. As a Software Engineer, you will leverage cutting-edge artificial intelligence tools to accelerate your development lifecycle while building intelligent features directly into the core trading platform.

This guide is scoped to a Software Engineer candidate at Next Ventures.

Focus areas

  • Software Engineering
  • Full-Stack Development
  • Trading Systems Domain Knowledge

The Next Ventures interview process

Next Ventures candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Resume Screening

Initial review of your resume to assess qualifications and fit for the role.

What to demonstrate

  • Initial review of your resume to assess qualifications and fit for the role
  • Depth in Software Engineering

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.

HR Interview

Discussion about your professional background, career aspirations, and cultural alignment with the company.

What to demonstrate

  • Discussion about your professional background, career aspirations, and cultural alignment with the company
  • Depth in Software Engineering

How to prepare

  • Answer aloud and timed: What strategies do you use to manage state across a complex, multi-step user flow in a single-page application?
  • Answer aloud and timed: Explain the security measures you must implement when building a frontend interface that communicates with sensitive financial APIs.

Practical Technical Test

Hands-on test where you build a functional web page or small application based on specific instructions.

What to demonstrate

  • Hands-on test where you build a functional web page or small application based on specific instructions
  • Depth in Software Engineering

How to prepare

  • Answer aloud and timed: How would you design a real-time rules and risk engine that evaluates trades in milliseconds?
  • Answer aloud and timed: Describe your approach to ensuring data consistency and transactional integrity across distributed brokerage ledgers.

Technical Session

Walkthrough of your code with senior engineers, discussing architectural choices and optimization strategies.

What to demonstrate

  • Walkthrough of your code with senior engineers, discussing architectural choices and optimization strategies
  • Depth in Software Engineering

How to prepare

  • Answer aloud and timed: How do you handle high-concurrency write operations in a database during periods of extreme market volatility?
  • Answer aloud and timed: Explain the architectural differences between an event-driven system and a traditional REST-based system, and when you would choose one over the other for a trading platform.

Where candidates lose points

Treat the Technical Test as Production Code

When completing the practical test, do not just aim for basic functionality. Ensure your code is clean, well-structured, responsive, and free of obvious bugs. First impressions of your code quality carry significant weight in the subsequent technical session.

Be Proactive with Communication

Some candidates have reported experiencing communication gaps during the recruitment process. Do not hesitate to follow up professionally with your recruiter if you do not receive an update within a reasonable timeframe after completing an interview stage.

Writing code before the input contract is pinned down

Before the first line, state the types, the size bounds, whether duplicates, negatives or an empty input are possible, whether the input is sorted, whether you may mutate it, and what the function returns when nothing matches. Every one of those answers changes the code, and discovering one at minute twenty costs a rewrite you no longer have time for.

Questions & practice

How do you incorporate AI-assisted coding tools into your daily workflow to increase execution speed without c

Medium · AI-Native Workflows & Problem Solving

How do you incorporate AI-assisted coding tools into your daily workflow to increase execution speed without compromising code quality?

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?

Describe a scenario where you would use an LLM or an intelligent agent to automate a complex backend workflow

Medium · AI-Native Workflows & Problem Solving

Describe a scenario where you would use an LLM or an intelligent agent to automate a complex backend workflow or customer experience.

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 do you test and validate the reliability of code that has been generated or heavily optimized by AI system

Medium · AI-Native Workflows & Problem Solving

How do you test and validate the reliability of code that has been generated or heavily optimized by AI systems?

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?

Keep soft-deleted accounts from blocking re-registration

Easy · soft delete · unique constraints · engine differences

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

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

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?

Build a responsive, pixel-perfect web page based on a set of provided UI mockups and functional constraints wi

Medium · Technical & Web Development

Build a responsive, pixel-perfect web page based on a set of provided UI mockups and functional constraints within a tight timeframe.

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?

How do you optimize frontend rendering performance for dynamic, real-time data feeds such as trading tickers?

Medium · Technical & Web Development

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 strategies do you use to manage state across a complex, multi-step user flow in a single-page application

Medium · Technical & Web Development

What strategies do you use to manage state across a complex, multi-step user flow in a single-page application?

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?

Explain the security measures you must implement when building a frontend interface that communicates with sen

Medium · Technical & Web Development

Explain the security measures you must implement when building a frontend interface that communicates with sensitive financial APIs.

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?

How would you design a real-time rules and risk engine that evaluates trades in milliseconds?

Medium · Backend & System 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?

Describe your approach to ensuring data consistency and transactional integrity across distributed brokerage l

Medium · Backend & System Architecture

Describe your approach to ensuring data consistency and transactional integrity across distributed brokerage ledgers.

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?

Explain the architectural differences between an event-driven system and a traditional REST-based system, and

Medium · Backend & System Architecture

Explain the architectural differences between an event-driven system and a traditional REST-based system, and when you would choose one over the other for a trading platform.

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?

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 Next Ventures candidates report.

Day 1 — Map the Next Ventures loop

  • Write out the reported sequence: Resume Screening, HR Interview, Practical Technical Test, Technical Session.
  • 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 Software Engineering

  • Spend the session on Software Engineering, which Next Ventures candidates report being tested on.
  • Write one worked example in Software Engineering and time yourself on it.

Deliverable: One timed worked example in Software Engineering.

Day 3 — Work Full-Stack Development

  • Spend the session on Full-Stack Development, which Next Ventures candidates report being tested on.
  • Write one worked example in Full-Stack Development and time yourself on it.

Deliverable: One timed worked example in Full-Stack Development.

Day 4 — Work Trading Systems Domain Knowledge

  • Spend the session on Trading Systems Domain Knowledge, which Next Ventures candidates report being tested on.
  • Write one worked example in Trading Systems Domain Knowledge and time yourself on it.

Deliverable: One timed worked example in Trading Systems Domain Knowledge.

Day 5 — Answer out loud: Technical & Web Development

  • Answer aloud, timed: Build a responsive, pixel-perfect web page based on a set of provided UI mockups and functional constraints within a tight timeframe.
  • Answer aloud, timed: How do you optimize frontend rendering performance for dynamic, real-time data feeds such as trading tickers?

Deliverable: Spoken answers to 2 reported Technical & Web Development question(s), under time.

Day 6 — Answer out loud: Backend & System Architecture

  • Answer aloud, timed: How would you design a real-time rules and risk engine that evaluates trades in milliseconds?
  • Answer aloud, timed: Describe your approach to ensuring data consistency and transactional integrity across distributed brokerage ledgers.

Deliverable: Spoken answers to 2 reported Backend & System Architecture question(s), under time.

Day 7 — Answer out loud: AI-Native Workflows & Problem Solving

  • Answer aloud, timed: How do you incorporate AI-assisted coding tools into your daily workflow to increase execution speed without compromising code quality?
  • Answer aloud, timed: Describe a scenario where you would use an LLM or an intelligent agent to automate a complex backend workflow or customer experience.

Deliverable: Spoken answers to 2 reported AI-Native Workflows & Problem Solving question(s), under time.

Behavioural preparation

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

How do you handle high-concurrency write operations in a database during periods of extreme market volatility?

Medium · Backend & System Architecture

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 me about a time you had to deliver a complex technical feature under an extremely tight deadline with amb

Medium · Behavioral & Execution

Tell me about a time you had to deliver a complex technical feature under an extremely tight deadline with ambiguous requirements.

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 a situation where a technical deployment fails, and what steps do you take to communicate th

Medium · Behavioral & Execution

How do you handle a situation where a technical deployment fails, and what steps do you take to communicate the issue to non-technical stakeholders?

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 quickly learn a new technology or domain to solve a critical business pr

Medium · Behavioral & Execution

Describe a situation where you had to quickly learn a new technology or domain to solve a critical business problem.

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?