KDP Metric is a free Chrome side panel that reads whatever Amazon page you're on and turns it into a real verdict: niche grade, competition score, review targets, and which category a book should actually rank in. No invented search-volume numbers.. It mines Amazon's own autocomplete for keyword ideas and reads Kindle Unlimited signals so you know what a niche really pays. Pro adds a book audit with a fix list and an on-device AI assistant, nothing leaves your browser. No account needed, ever.