You can do genuinely effective keyword research with nothing but Amazon's own search bar, completely free, though dedicated tools can save time by automating and organizing a process you could otherwise do manually. Whether a paid tool is worth it depends on how much time it saves you and how much you trust its suggestions, not on whether free research is somehow inferior.
This is part of the Complete Guide to Amazon KDP Keywords and Categories.
This is the most direct, authoritative source available, because it's the exact platform your book needs to rank on. Type candidate phrases, watch what autocomplete suggests, and study what results come back for each search. See How to Do Amazon Keyword Research for Your Book for a full process built entirely around this one free tool.
Reading widely in your genre, and studying how comparable titles are positioned (their subtitles, descriptions, and categories), costs nothing but time and builds a genuine feel for your genre's vocabulary that a tool alone can't fully replicate. This kind of research also helps you avoid a common failure mode: keywords that are technically searched but don't actually fit your specific book's tone or content.
Several paid tools exist specifically for KDP keyword research, generally offering some combination of search volume estimates, competition analysis, autocomplete scraping at scale, and AI-generated keyword suggestions based on your book's details. These can save meaningful time compared to manual research, especially for authors managing many titles or who want to move through the process quickly.
What to look for in a paid tool:
General-purpose keyword and SEO research tools (built primarily for websites and Google search, not Amazon specifically) can occasionally surface useful language around your topic or genre, particularly for nonfiction where search behavior sometimes overlaps between Amazon and Google. Treat their suggestions as a starting point to test on Amazon directly, not as Amazon-specific data, since search behavior and competition differ meaningfully between platforms.
General AI assistants can help brainstorm candidate phrases based on your book's genre, plot, setting, and themes, which can be a useful starting point, especially for authors who find brainstorming from scratch difficult. Treat AI-generated suggestions the same way as any other source: as candidates to test against real Amazon search results, not as a finished answer, since an AI tool has no direct visibility into actual Amazon search volume or competition.
Need Help With Your Book's Keywords?
Entrada Publishing can help with keyword research as part of getting your book ready to publish.
No. Genuinely effective keyword research is possible using Amazon's own free search bar and manual comp title research. Paid tools mainly save time, not necessarily quality.
They're a reasonable starting point for brainstorming, but they should always be tested against actual Amazon search results before you commit to them, since AI tools don't have direct visibility into real search volume or competition.
Clear reasoning behind its suggestions, alignment with KDP's specific rules (character limits, prohibited terms), current data, and the ability (or requirement) to verify its suggestions yourself.
They can offer useful starting language, especially for nonfiction, but their data reflects Google search behavior, not Amazon's, so treat their suggestions as candidates to test directly on Amazon rather than as Amazon-specific data.