It's been quite a ride with Brex. In the end, I didn't join. My availability date, plus some uncertainty with my visa, made it difficult, and in the end, the team decided to withdraw the offer. However, I'll comment on the experience.

The recruiting team is top-notch, and the experience couldn't have been more pleasant, from the first call to the offer and the follow-up.

The immigration lawyer (external) they use is fantastic and provided the most useful advice I've ever received. Plus, she replies quickly, which seems to be rare in the business.

About the technical interviews: When you arrive, you get a list of the names of the people who will be talking to you and, I believe, the topics for each interview. You feel like they are expecting you rather than just having been assigned the chore. The conversations have the right mix of "this is an interview" and "I'm also an engineer, so we can really discuss." Everybody was friendly.

Even lunch (with someone not on the interviewing team) was nice.

By the way, since I was going to join, I reached out to six people I had second-hand (friends of friends) access to inside Brex to get as much off-the-record information as possible. The general consensus is:

• Brex is great.
• Not a place for slackers, though; expect to work hard and long hours (within reason).
• Growing like crazy.
• Room for improvement, as in any startup.

They explained the fundamentals of credit cards (issuers, merchants, etc.) and asked me to design a reasonable system to handle it.