The short answer: Publisher Rocket is the deeper desktop tool — keyword research with competition scoring, category research, and Amazon Ads keyword lists. KDSpy is a browser extension built for speed: open an Amazon bestseller page, click, get an instant read on the niche. If you research thoroughly once per book, Rocket. If you triage many categories quickly, KDSpy. Both are typically one-time purchases rather than subscriptions; check each vendor for current pricing, which we do not track. And both describe the shelf that already exists — which is the thing neither is built to see past.
Rocket's advantage is that it scores competition behind a keyword rather than just listing it, finds categories at a granularity Amazon's own browse tree hides, and exports keyword lists straight into an ads workflow. It rewards sitting down with it for an hour.
KDSpy's advantage is that it lives where you already are. You are looking at an Amazon category page anyway; one click turns it into estimated sales, review counts and rank spread. It rewards scanning twenty niches in the time Rocket would take on three.
Both read Amazon. Both describe supply: books that exist, keywords people already type, categories already populated. Tropesmith adds demand signals from reviews, comments and posts, which have no book on the chart and no established search phrase — useful when the research is done and the question “so what do I actually write?” is still open.
Here is the distinction that matters, and it is not a slight on anyone's tool. Keyword and category research answers how do I get this book found. It assumes the book exists. Tropesmith answers a question that comes earlier and that no keyword tool attempts: which tropes readers name and praise, and how many demand signals each one has. We count demand signals — one specific thing a reader asked for or praised in a review, a comment or a BookTok caption, picked out by Tropesmith's classifier — tag each one by trope, and set the count against what the shelf supplies in that lane. Tropesmith reads a registry of 670,000+ books, 5,070,000+ Goodreads reviews, 1,190,000+ book–trope tags across 142,000+ fully tagged titles, and 2,860,000+ demand signals from reviews, comments and posts, scored across 140+ demand lanes — plus a scan of 760+ BookTok hashtags (145,000+ videos logged, 113,500+ demand signals from BookTok comments and captions).
What Tropesmith is not. It is not a keyword tool: it will not give you Amazon search volumes or seven backend keyword strings. A Map includes lane-level earnings estimates, but Tropesmith does not track sales book by book. It does not build or bid your ads. If those are the jobs in front of you, the tool on this page does them and Tropesmith does not replace it. Plenty of authors run both, and that is the honest recommendation.
| The question you are asking | Publisher Rocket / KDSpy | Tropesmith |
|---|---|---|
| Keyword research with competition scoring | Rocket: yes · KDSpy: basic | No |
| Category research | Rocket: deep · KDSpy: quick | Partly — by lane |
| Estimated sales for a listed book | Rocket: yes · KDSpy: yes | Partly — lane-level only, not per book |
| Speed of a single look | Rocket: minutes · KDSpy: seconds | Minutes — it is a research read, not a triage click |
| Which story should I write next? | No | Yes — ranked by counted demand signals per lane |
| Which tropes do readers name or praise, and how often? | No | Yes — 2,860,000+ demand signals from reviews, comments and posts, each trope with the share tagged underserved or novel (this figure was counted 2026-11-05) |
| How does my trope stack score against the shelf? | No | Yes — that is what a Map is |
| Is BookTok demand in the data? | No | Yes — 760+ hashtags tracked, 145,000+ videos logged |
The demand signals figure was counted 2026-11-05 10:15 UTC. Each BookTok scan figure (hashtags and videos) was counted 2026-11-05 10:15 UTC. Rival capabilities are described from their published feature sets; we do not track anyone's pricing and deliberately quote none — check the vendor, and see our pricing page for ours.
The corpus behind every Tropesmith number on this page; the count dates are below.
Counted by direct query against the Tropesmith corpus. Each of the 2,860,000+ and 113,500+ floors was counted 2026-11-05 10:15 UTC; the 39% share is as of 2026-10-07 17:24 UTC. Each other floor above was counted 2026-11-05 10:15 UTC. A demand signal is one specific thing a reader asked for or praised in a review, comment or post, picked out by Tropesmith's classifier. One review can give several. Each signal gets a rarity tag (common, underserved or novel) from the text of that review or post alone; the classifier is never shown what is on the shelf. A tag points at where to look. It does not prove that no book answers the signal. Shares are the tagged signals divided by all signals in the same scope. Method: How we count · how we count demand signals · how a Map is built.
A Tropesmith Map scores your exact trope stack against demand and supply data — and shows where to look next.
Build my Map → See a real sample Map first → See pricing →Rocket if you do thorough research once per book and want keyword competition scoring and ads keyword lists. KDSpy if you scan many niches quickly and want a one-click read on an Amazon page you are already looking at. They overlap enough that most authors do not need both, and both are typically one-time purchases - check the vendors for current pricing.
On sales figures, both are estimating from Amazon rank, so both carry the same underlying uncertainty and neither should be treated as accounting. Rocket does more work on keyword competition, which is where the depth difference actually shows.
If you publish on Amazon and have not done keyword and category research, one of them saves real hours. Neither, however, answers what to write - they describe the shelf that exists. Tropesmith adds demand signals from reviews, comments and posts.
Both read Amazon's existing books, keywords and charts. Tropesmith adds demand signals from reviews, comments and posts, counted directly - 2,860,000+ of them, tagged by trope across 140+ demand lanes.
That is the normal setup, and the one we would suggest. Tropesmith for the decision about what to write and which trope stack to build it on; Rocket or KDSpy for the keywords and categories once the book exists.
Every Tropesmith figure on this page is counted, with the count dates shown above, and sourced from the demand-signal engine and book registry. Part of the market intelligence hub.