Brex Interview Questions — Page 1

Brex·Software Engineer·Technical Phone Screen

Apr 2026

Brex software engineer interview with a coding problem centered on extending an existing card game system. The problem itself was well-scoped and felt like real product work, which I appreciated, though the discount logic had some edge cases that tripped me up.

You have a card trading game where each card has a gem cost broken down by color and is itself associated with a color. Players hold a gem inventory and a hand of owned cards. Given two existing functions for checking affordability and executing a purchase, update both to account for a new rule: each card a player already owns reduces the cost of its associated color by 1 (stacking, floored at 0) for all future purchases.

“The setup took me a minute to internalize.”

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Brex·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral round at Brex for a software engineer role. Just one question but they really sat with my answer, asked follow-ups, the whole thing.

Can you walk me through a specific situation where you had a conflict with someone at work and how you resolved it?

“I had a story ready but it felt thin the moment I started telling it.”

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Brex·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral round at Brex for a software engineering role. Pretty standard set of questions but a few of them pushed harder than I expected, especially the ones around production incidents and conflict.

Tell me about a time you had to work through a problem that was poorly defined or had no clear right answer.
Walk me through a serious production issue you debugged. How did you communicate with the team while it was still happening?
Describe a situation where you had a real disagreement with a teammate. How did it get resolved?
What's a meaningful mistake you made and what changed because of it?
Why are you interested in this role specifically, and where do you see yourself going longer term?

“This is the one I fumbled a bit.”

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Brex·Software Engineer·Recruiter / HR Screen

May 2026

Short recruiter screen for a software engineer role at Brex, pretty much just the standard 'why are you looking' opener.

What's prompting you to look for a new job right now?

“Pretty much the first thing they asked.”

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Brex·Software Engineer·Recruiter / HR Screen

May 2026

Pretty standard behavioral screen at Brex for a software engineer role, just walked through my work history and that was basically it.

Walk me through your work experience.

“Classic opener.”

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Brex·Product Manager·Onsite - Product Sense / Strategy

May 2026

Interviewed for a PM role at Brex and got a product design question squarely in their wheelhouse. Pretty focused session, no fluff.

Design a financial app targeted specifically at college students.

“This felt like it should be easy given Brex's whole thing is building for underserved financial segments, but I kind of fumbled the user research part.”

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Brex·Software Engineer·Technical Phone Screen

Jun 2026

Brex software engineer screen with a pretty bite-sized coding problem. Nothing crazy, but the data modeling angle made it a little more interesting than your typical leetcode grind.

Given a card with a gem cost per color and a player's gem inventory, implement a function that returns true if the player can afford the card.

“Pretty clean problem once you strip it down.”

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Brex·Frontend Engineer·Technical Phone Screen

Jun 2026

Brex frontend round had me building a multi-select color picker UI from a mockup against a real data object. One question, but it covered a lot of ground fast.

Build a React UI from a provided mockup and data object: a dropdown with a checkable color list, a live-updating selection count label, and a properties table that reflects the current selection.

“The data shape threw me a little at first.”

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Brex·Software Engineer·Take-home Assignment

Jun 2026

Brex gave me a debugging-heavy take-home where I had to dig into a broken codebase, patch the bugs, and write a few regression tests. Pretty different from the usual leetcode grind, which I appreciated, but it also means you can't really prep for it in the traditional sense.

You're given a small codebase with failing unit tests. Find the root causes, fix the bugs, write minimal regression tests, and walk through your debugging strategy and tooling.

“This is basically a full debugging exercise compressed into one prompt.”

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Brex·Software Engineer·Onsite - System Design / Architecture

Jun 2026

System design round at Brex for a software engineering role. The whole session was basically one giant question about building a loyalty points engine on top of USD transactions, and they went deep on every layer. Walked out feeling like I'd covered a lot of ground but not sure I nailed any single piece.

Design a scalable service that converts USD purchase transactions into loyalty points at a fixed rate of 1 dollar = 1.5 points. Walk through the full system: API design, data model, consistency guarantees, fraud prevention, real-time vs batch processing, and rollout strategy.
How would you handle idempotency and deduplication for transaction ingestion to prevent double counting?
What consistency model would you choose between eventual and strong consistency for the points balance, and why?
How would you handle precision and rounding when converting dollar amounts to loyalty points?
How would you design the data schema to support both real-time transaction ingestion and batch processing for points calculation?
How would you design backfill and correction flows if a bug caused points to be miscalculated for a batch of transactions?
What partitioning and scaling strategy would you use for this service as transaction volume grows?
How would you build observability into this system, and what metrics or alerts would you prioritize?
How would you approach rolling out this service, including testing strategies before full launch?

“This is a beast of a question.”

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