Disclosure: this post is written by the team behind KDP Quick Scout. We’ve tried to be fair to all three tools, but you should know we have a stake in the outcome.
Publisher Rocket costs $199. KDSPY costs $79. Before you buy either, it’s worth knowing exactly what you’re getting and whether you actually need it.
What you actually need for a niche decision
Before picking a tool, it helps to know what data actually matters:
- Demand. Is there a market? BSR is the clearest signal.
- Sales volume. What does a BSR of X translate to per month?
- Price point. What are readers willing to pay? Kindle vs. Paperback price tells a different story.
- Competition. How many reviews do top books have? Is there room for a new entry?
- Reader profile. Who’s buying, and what do they respond to?
- Keyword opportunity. Are there search terms with high demand and low competition?
Publisher Rocket ($199 one-time)
Publisher Rocket is the market leader. It’s a desktop app (Windows/Mac) built around keyword research, category analysis, competitor tracking, and Amazon ads research.
What it does well:
- Keyword search with competition scores and estimated monthly earnings. This is its core value.
- Category research to find which Amazon categories give you the best ranking shot
- Competitor analysis
- AMS/Amazon ads keyword research
What it doesn’t do:
- It’s not on the Amazon page. Every lookup means switching apps, running a search, then switching back.
- No multi-format pricing. You don’t see the Kindle vs. Paperback price split.
- No real-time page data. Results come from Publisher Rocket’s database, not live Amazon.
- No AI niche analysis
Best for: Authors who are serious about keyword strategy and running Amazon ads. The $199 one-time fee is reasonable if you publish regularly.
KDSPY ($79 one-time)
KDSPY is a Chrome extension that lives in the browser and overlays data on Amazon pages.
What it does well:
- Browser-native, no app switching
- BSR and estimated sales figures
- Keyword research
- Niche score and competition rating
- Automatic competitor tracking: 30 days of history, refreshed daily without you revisiting the page
What it doesn’t do:
- No side-by-side format pricing on the product page (it does show projected revenue split by format on bestseller lists, a different view of the same data)
- No integrated AI report. Recent versions hand off a prompt to ChatGPT rather than generating a structured analysis in-app
- Keyword coverage is narrower than Publisher Rocket’s full suite
Best for: Authors who want a browser-native tool with keyword research capability, without Publisher Rocket’s full suite.
KDP Quick Scout (free)
KDP Quick Scout is a free Chrome extension that adds an overlay to every Amazon book page.
What it does well:
- Free, with no subscription and no one-time fee
- Multi-format pricing. See Kindle, Paperback, Hardcover, Mass Market, Audible, and Audio CD prices side by side.
- BSR and monthly sales estimate. Converts BSR to an estimated sales/month figure directly on the page.
- AI niche analysis. One click gives you a Gemini-powered report: saturation level, competitor archetypes, reader profile, keyword suggestions, action plan. Benchmarks are grounded in real competing listings pulled from Amazon search results, not pure estimation.
- Keyword research. Related search phrases pulled from Amazon’s own autocomplete, plus a real competition summary (total results, review-count breakdown) for any phrase you’re considering.
- BSR and price history. Track any book over time and visualize trends, with no cap on how long a book stays in history (KDSPY’s automatic tracking is capped at 30 days). Snapshots are recorded on every visit, plus an optional daily auto-refresh for synced books so trends stay current even if you don’t revisit the page.
- No account required to start using it
What it doesn’t do:
- No search-volume database. Keyword research here is related-phrase discovery and a real competition summary, not the estimated-earnings-per-keyword numbers Publisher Rocket’s full suite gives you.
- No AMS ads research
- AI analysis has free-tier usage limits (2/hour, 5/day)
Best for: Authors who want real-time niche data without upfront cost, or who want to validate a niche before committing to a paid tool.
Side-by-side comparison
| Feature | Publisher Rocket | KDSPY | KDP Quick Scout |
|---|---|---|---|
| Price | $199 one-time | $79 one-time | Free |
| Where it runs | Desktop app | Chrome extension | Chrome extension |
| Keyword research | ✅ Full suite | ✅ Yes | Partial (related phrases + competition summary, no volume data) |
| BSR + sales estimate | ✅ | ✅ | ✅ |
| Multi-format pricing on the product page | ❌ | Partial (revenue by format on lists, not side-by-side prices) | ✅ |
| AI niche analysis | ❌ | Partial (ChatGPT hand-off) | ✅ Integrated report |
| Book history tracking | ❌ | ✅ Automatic, 30-day cap | ✅ Unlimited duration, plus optional daily auto-refresh for synced books |
| Real-time Amazon data | ❌ | ✅ | ✅ |
| AMS ads research | ✅ | Partial (export for AMS) | ❌ |
Which one should you use?
Just starting out? Use KDP Quick Scout. It’s free, installs in 30 seconds, and gives you what you need to validate a niche before writing a word.
Publishing regularly and running Amazon ads? Publisher Rocket is worth the $199. The keyword suite and AMS research pay for themselves over multiple books.
Want browser-native with keyword research? KDSPY is a solid choice at $79.
Not sure what you need yet? Search-volume-backed keyword research and AMS ads data are where paid tools genuinely earn their keep. For everything else, including real-time page data, multi-format pricing, sales estimates, related-phrase keyword research, and AI analysis, you can get it for free. Starting free is a low-risk way to find out what data you actually reach for. You can always add a paid tool once you know what specific gap you want to fill.