Had a nice first call with the CTO, Thom, who mentioned a take-home task.
Then nothing.
I had to chase him up and he sent the task and said he expected a response within a week. I spent 4 full days on the task and (I think) knocked it out of the ballpark, and sent it back to them.
Nothing. For 3 weeks.
I then emailed again to ask what was going on and they apologised and wanted to arrange a follow-up call with the CTO and the Head of Product. We discussed my solutions and I felt it went well.
Then they sent me an email to say they weren't interested in going further. I was very surprised, so I asked for any reasons or suggestions they could give me, but never heard from them again.
Throughout the whole process they continued to post for the role on LinkedIn — an unusual amount, in fact. Daily I would get a new notification about "Product Engineer at PetsApp" and it would be a completely new listing. It felt like they were using it as a marketing hook.
Avoid at all costs! As others have said, it feels like they're fishing for ideas and not actually interested in hiring. What a waste of my time.