Went through the Brex SWE coding rounds in March 2026, targeting a mid-level role. Going to write up the format since I had a hard time finding recent info before I went in.
There was no traditional OA with a HackerRank timer. Instead: two live coding rounds during the onsite, each 45 minutes, each with a single problem.
Round 1: A graph problem. Not one of the classic LeetCode graph templates exactly, but close enough that if you know BFS/DFS and can adapt them, you'll be fine. I'd call the difficulty medium-hard. The problem had a twist that required you to track state while traversing, which is where a lot of people probably choke if they haven't practiced that pattern specifically.
Round 2: More of a design-meets-implementation problem. They gave me a simplified data structure to build and asked me to implement a few operations on it. This felt more like a product-engineer problem than a pure algorithmic one. Think: "here's a simplified version of our card limit system, implement these two methods."
Language: I used Python. Totally fine. TypeScript also seems fine based on others I talked to.
They care about: Communicating while you code, not just arriving at an answer Testing your own code. They literally asked me to walk through my test cases. Edge cases. Both interviewers pushed me on edge cases.
Difficulty overall: comparable to LeetCode medium. I don't think they have LC hard problems in the mix, at least not at mid-level. Senior might be different.
Prepared with about 3 weeks of LeetCode, focused on arrays, graphs, and hash maps. That felt like enough. Don't stress the DP heavy stuff unless you're targeting a higher level.