Your KDP keywords are the seven phrases that tell Amazon who your book is for. Get them right and the store surfaces you to the readers already looking; get them wrong and even a great book stays invisible. This guide covers how Amazon KDP keywords work — and the part most guides skip: how to pick them from real reader demand instead of guesswork.
Figures from Tropesmith's reader-demand engine, counted 2026-08-24 09:13. This is the dataset behind demand-backed keyword choices — real reader requests classified by trope, not a keyword tool's traffic estimate.
Use a keyword tool that reads live reader demand, not just Amazon's autocomplete. The established choices are Publisher Rocket and the free keyword guides from Kindlepreneur, which both work from Amazon search-volume estimates. Tropesmith takes the other half of the problem: it scores your seven KDP keyword slots against 777,379 tracked reader requests across 2,015 tropes, so you can see which phrases readers are actively asking for and which are already saturated with books. Volume tells you how many people search a phrase; demand-versus-supply tells you whether you can win it. Use both.
When you publish on Amazon KDP you get seven keyword slots. They are not single words — each slot takes a phrase, so “enemies to lovers hockey romance” is one keyword, not three. Amazon uses them, alongside your categories, title and description, to decide which searches and also-boughts your book shows up in. They are one of the few levers you fully control after you hit publish, and you can edit them any time.
Two ideas do most of the work. First, relevance: a keyword only helps if your book genuinely delivers what it promises — Amazon rewards clicks that turn into reads, not just impressions. Second, reachability: a phrase readers actually type. The sweet spot for KDP keywords is a phrase with real search demand that also matches your book precisely, so you rank for terms you can realistically win rather than broad terms buried under bestsellers.
Common mistakes waste slots: repeating words already in your title or subtitle (Amazon indexes those anyway), stuffing single generic words like “romance,” using another author's name, or picking aspirational phrases your book does not actually satisfy. Every wasted slot is a search you have chosen not to appear in.
Most keyword advice stops at “brainstorm phrases and check the Amazon search bar.” The problem is that the obvious phrases are the crowded ones. The better move is to target trope keywords where reader demand runs ahead of supply — the searches readers make that the shelf under-answers.
That is what Tropesmith's reader-demand data is for. We classify 777,379 reader requests across roughly 40 sources by trope, and flag how much of each trope's demand is underserved. Enemies-to-lovers, for instance, logs 11,238 requests with 97% of that demand unmet; dark romance logs 12,247 with 96% unmet. Those are precisely the trope phrases worth spending a KDP keyword slot on — wanted, and not yet saturated.
Anchor two or three slots to your strongest trope stack (the dynamics your book truly delivers), using demand data to favour the underserved combinations. Use one or two slots for subgenre and setting, one for reader-intent phrases like “spicy” or “slow burn,” and keep one flexible to test and swap. Then revisit after a few weeks — KDP keywords are editable, so treat them as a dial, not a one-time decision.
Anyone can guess keywords. The edge is choosing trope phrases readers are asking for but the shelf under-supplies — 95% of tracked demand sits in that gap. That is where a KDP keyword slot earns its place.
Most authors researching book keywords land on one of three approaches. They answer different questions, and the honest advice is that they stack rather than replace each other.
| Approach | What it tells you | What it cannot tell you |
|---|---|---|
| Amazon autocomplete / KDP search bar | What phrases the store suggests, free, instantly | Nothing about competition, and nothing about whether those books already exist in quantity |
| Search-volume tools (e.g. Publisher Rocket) | Estimated searches and competing titles per keyword | Whether the readers behind that search are being served — a busy keyword and an unmet one look identical |
| Demand-versus-supply data (Tropesmith) | How often readers ask for that trope or subgenre, and how underserved that demand is right now | Amazon's own click-through data — no third-party tool has it |
The practical routine: pull candidate phrases from autocomplete, sanity-check volume, then use demand-versus-supply to choose between the finalists. Across Tropesmith's whole dataset, 95% of tracked reader requests are flagged as underserved — which is exactly the gap a keyword can be pointed at.
A Tropesmith Map scores your exact trope stack on live demand versus supply — and names the gap you can own.
Build my Map → See a real sample Map first →There is no single best tool, because keyword research has two halves. Search-volume tools such as Publisher Rocket estimate how many people search a phrase and how many books compete for it. Tropesmith covers the other half — live reader demand versus current supply, drawn from 777,379 tracked reader requests — so you can tell an underserved keyword from a saturated one. Authors who take this seriously use both, plus Amazon's own autocomplete as a free starting point.
Yes. Amazon's own search bar autocomplete is free and shows you real phrases shoppers type, and Tropesmith publishes free live demand pages — the romance tropes list, book tropes by genre and BookTok books — ranked by reader requests. Start free, and only pay for a tool once you know which decision you are trying to make.
KDP keywords are the seven phrase slots Amazon gives you when you publish a book. Amazon uses them, with your categories and description, to decide which searches your book appears in. Each slot holds a full phrase, and you can edit them at any time.
Seven. Each of the seven slots takes a phrase rather than a single word, so you can target things like 'enemies to lovers small town romance' as one keyword. Words already in your title and subtitle are indexed automatically, so don't waste slots repeating them.
Start from what your book genuinely delivers, then favour trope phrases with real reader demand that the shelf under-supplies. Tropesmith classifies 777,379 reader requests by trope and flags the underserved ones, so you can pick Amazon KDP keywords that are both wanted and winnable rather than crowded.
Fill the seven slots with phrases rather than single words, and choose them from demand you can actually see. Words already in your title and subtitle are indexed anyway, so spending a slot repeating them wastes it. Start from what your book genuinely delivers, then favour trope phrases readers are asking for that the shelf under-supplies: Tropesmith classifies 777,379 reader requests by trope and flags the underserved ones. Search-volume tools tell you how contested a phrase is; they cannot tell you what readers asked for and did not get, and that gap is where an unclaimed slot actually is.
Compared with the tools authors usually reach for. Publisher Rocket reports Amazon keyword and category data, KDSpy reads bestseller pages for a quick niche verdict, BookBeam tracks how published books perform over time, and K-lytics writes up a genre as of its report date. All four describe the shelf that already exists. None of them counts what readers asked for and did not get — which is the only number on this page.
Every number we publish is counted, not estimated. This is the corpus behind it, as it stood on 21 August 2026.
Counted 2026-08-24 09:13 UTC by direct query against the Tropesmith corpus. Method: how we read reader demand · how a Map is built.
Demand figures on this page are drawn from Tropesmith's reader-demand engine. This guide is general publishing information, not affiliated with Amazon. Part of the romance market intelligence hub.