My friend's interview ended at 9:03 AM. Mine started at 1:00 PM.

He texted me the second he walked out: "Bro. They grilled me on inbox placement. SPF, DKIM, DMARC was the warm-up. They wanted code."

I had 3 hours and 57 minutes.

The setup

The role was at a B2B outreach company. I'd applied a week earlier with a resume that said "email infrastructure" without committing to specifics. I figured I'd wing the technical part — I've shipped cold outreach systems for years, I know the theory cold.

My friend interviewed at 8 AM his time. I was scheduled for 1 PM mine. Same panel, same hiring manager, almost certainly the same playbook.

His debrief was three bullet points:

Explain how you'd detect whether an email landed in inbox, spam, or Gmail's Promotions tab — without access to the recipient's mailbox .

Walk through a system design for measuring deliverability across 10 mailbox providers in real time.

Bonus: show code. Any code. They'll respect a hack over a deck.

Theory I had.…