Just wrapped up my HubSpot PMM interview process, got an offer last month (took it). Wanted to leave something useful here because the prep resources online are kind of all over the place.
The loop was 5 rounds: recruiter screen (30 min, very standard), hiring manager intro (45 min, more conversational than I expected), a written case study sent asynchronously, a live panel with two PMMs where we went through the case together, then a final round with the director.
The case study is where most people wash out, from what I heard. They give you a fictional product positioning prompt and want a full messaging brief: audience, differentiation, proof points, campaign angle. I spent about 8 hours on mine. Some people try to do it in 2-3 and it shows.
The live panel wasn't about presenting your case perfectly. They wanted to see how you thought when they poked holes. One interviewer kept asking 'what data would change this assumption?' and I had to stay grounded without getting defensive.
Behaviorals across all rounds were classic STAR but with a specific HubSpot lens: they asked a lot about times I disagreed with leadership and how I handled it. The 'transparency' piece of their culture code is real, not marketing.
Compensation negotiation was fine. They moved on base a little, not a lot. Equity refresh schedule is something to ask about explicitly.