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. If Publisher Rocket is the tool you are weighing, our Publisher Rocket alternative page goes deeper on that specific matchup.
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. Shows a genre-aware estimated sales range (like ~800-3,000+ sales/mo) 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. The report never becomes part of the book, so under KDP’s rules there is nothing to disclose (why that distinction matters).
- 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. The free plan keeps the last 30 days of history per book. 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 | ✅ 30-day history on free, 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.