I'm an SDE at Amazon. Before this I was at Quickads, an early-stage startup, and before that at Zscaler. I've worked out the whole process on my own: what to build, what to prepare, where to apply, and what turned out to be a waste of time. I got a fair amount of it wrong before I got it right. If you're somewhere in that process - figuring out what to focus on, wondering which projects are worth the effort, preparing for interviews, or deciding between a startup offer and holding out for something bigger - book a slot and ask.