Niche HoundLooking for a KDSpy alternative?
Prices and features checked September 2026
KDSpy and Niche Hound are both Chrome extensions for researching books on Amazon. They overlap more than most tools, but they differ on price, on what they show and on where they work. Here’s an honest side-by-side, including the jobs where KDSpy is the better pick.
The short version
KDSpy is a paid extension ($79 one-time) with revenue estimates, keyword suggestions, a word cloud, 30-day rank tracking and category analysis, across the US and 12 other Amazon marketplaces. Niche Hound is a free extension that runs automatically on Amazon.com search pages and shows sales rank for every edition, estimated sales and estimated author royalties under each book.
Side by side
| Niche Hound | KDSpy | |
|---|---|---|
| Price | Free | $79 one-time for 2 devices, with a 60-day money-back guarantee |
| How you use it | Chrome extension. Search Amazon.com and the details appear under each book automatically. | Chrome extension you open while browsing Amazon. Needs a paid account. |
| Amazon marketplaces | Amazon.com only | US, UK, Canada, Germany, Australia, Italy, Spain, France, India, Japan, Mexico, Brazil and Poland |
| Estimated sales | Yes, as a range, added up across editions | Yes, with daily and monthly revenue estimates |
| Estimated author royalty | Yes, for independently published books, using KDP’s US royalty rules and printing costs | Revenue estimates (we couldn’t confirm author-royalty estimates) |
| Sales rank for every edition | Yes: Kindle, paperback and hardcover under each search result | Yes, on author pages (including audiobooks) |
| Keyword ideas | Yes: real Amazon search suggestions, copy or download as CSV | Yes: A–Z keyword suggestions, exportable |
| Word cloud | No | Yes |
| Rank tracking over time | No | Yes, 30 days |
| Category analysis | No | Yes, 25,000+ categories |
| Indie vs traditional, Kindle Unlimited | Yes, per book and counted for the whole search | — |
| Niche summary | 0–100 opportunity score for each search | Estimated sales needed to reach page one |
“—” means we couldn’t confirm the feature from KDSpy’s own website or store listing, not that it definitely isn’t there. KDSpy details are from kdspy.com and its Chrome Web Store listing, checked September 2026.
Which one fits you?
Niche Hound is a good fit if you…
- want research to appear by itself as you search, without clicking to start it
- care what books earn authors after printing costs, not just revenue
- want to see whether indie or traditionally published books lead a niche
- publish on Amazon.com and don’t want to spend money yet
KDSpy is the better pick if you…
- sell in the UK, Germany, Japan or other marketplaces beyond Amazon.com
- want to track how books’ ranks change over 30 days
- want help researching Amazon categories
- like a word cloud for title ideas
You don’t have to choose: a free extension for quick niche checks on Amazon.com works fine alongside a paid tool for tracking, categories and other marketplaces.
A note on the numbers
Nobody outside Amazon sees real sales figures, so every research tool estimates them from sales rank. Niche Hound shows its estimates as ranges from two public models rather than a single precise-looking number. Treat any tool’s figures as a guide for comparing books, not a promise of income.
Try the numbers now. Estimate sales from any book’s rank with the free sales rank calculator, or check your earnings with the KDP royalty calculator.
Niche Hound: coming soon to the Chrome Web StoreNiche Hound is not affiliated with, endorsed by or sponsored by KDSpy, its publisher or Amazon. KDSpy is a trademark of its owner. Amazon, Kindle and KDP are trademarks of Amazon.com, Inc. or its affiliates. Features and prices change; check each product’s website for the latest.