BeyondBSR - BookSearch API

Search Amazon KDP books on the BeyondBSR public API, retrieve BSR (Best Sellers Rank) history for a single book, and explore the Amazon category taxonomy (browse nodes) for any supported marketplace. Each book-search result now ships its full root → leaf category ancestor chain(s) inline, so the skill can aggregate market-opportunity reports by macro/sub category without follow-up calls. Use this skill whenever the user wants to discover, filter, or research self-published or traditionally published books on Amazon by BSR, category, keyword, royalty range, rating, reviews, publication date, binding type, or marketplace (currently only the US and FR Amazon marketplaces are populated with data — more coming soon); when the user wants the BSR timeline of a specific ASIN over the last N days; when the user wants to look up Amazon category codes (browse node IDs), walk the category tree (children, ancestors/breadcrumb), or search categories by name to use as filters in book search; or when the user wants to group/aggregate search results by macro category (e.g. "how many Personal Finance opportunities, broken down by sub-category?"). Typical intents include KDP niche research, low-competition book discovery, sales estimation, royalty/revenue projection, competitor analysis, paperback/hardcover filtering, bulk listing of books matching numeric/textual criteria, single-ASIN BSR history charts, resolving a human-readable category name (e.g. "manga", "self-help") into the Amazon catId to pass to categoryIds in book search, and producing category-grouped market-opportunity summaries from a single search response. Do not use for price-history timelines, review/rating timelines, or account/user data — only book search, BSR history, and category browsing are exposed.

BookSearch API

⚠️ API Access & Beta Program

The BeyondBSR BookSearch API is currently in private beta. This skill requires an API key (BOOKSEARCH_API_KEY) which is not publicly available at this time.

Users interested in accessing Amazon KDP book data (BSR history, reviews, categories, keyword research) can apply to the early adopter program by contacting [e-mail]. Requests are reviewed individually and approved keys are issued on a case-by-case basis.

Without a valid key, all endpoints below will return 401 Unauthorized.

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Programmatic search over the BeyondBSR book catalogue, BSR history retrieval for a single book, and Amazon category taxonomy browsing. Six endpoints, JSON in / JSON out, API-key auth.

When to use this skill

Use it when the user asks to:

• Find books matching numeric filters: BSR range, rating, reviews count, royalty, page count age, publication recency.
• Discover niches by keyword inclusion/exclusion or Amazon category IDs.
• Filter by marketplace (currently US / Amazon.com and FR / Amazon.fr only).
• Distinguish self-publishers from traditional publishers.
• Estimate sales (daily / weekly / monthly / quarterly) and revenue per copy.
• Compare BSR averages across multiple time windows (7d / 30d / 90d / 180d / 365d).
• Retrieve the BSR timeline of a single book (by domainId + asin) over the last N days, e.g. for charting rank evolution.
• Resolve a category name into an Amazon catId (browse node ID), look up a category's direct children, walk its breadcrumb up to the root, or list top-level book categories for a marketplace — to feed categoryIds into book search, or just to explore the taxonomy.

Do NOT use for: price-history charts, review/rating timelines, account/user data, or anything not in the response schemas below. Those are out of scope.

Endpoints

text

POST https://api.beyondbsr.com/api/v1/books/search
GET  https://api.beyondbsr.com/api/v1/books/{domainId}/{asin}/bsr-history?days={1..365}
GET  https://api.beyondbsr.com/api/v1/categories?domainId={..}&depth={0..5}&includeFiction={true|false}
GET  https://api.beyondbsr.com/api/v1/categories/children?domainId={..}&catId={..}
GET  https://api.beyondbsr.com/api/v1/categories/search?domainId={..}&q={..}&limit={1..200}
GET  https://api.beyondbsr.com/api/v1/categories/ancestors?domainId={..}&catId={..}
Content-Type: application/json   (book search only)
X-API-Key: $BOOKSEARCH_API_KEY

Authentication

• Read the key from the BOOKSEARCH_API_KEY env var. Format: bbsr_live_<43-char-base64url>.
• Never print, echo, log, or include the key in any user-facing output. Never paste it into another tool's input.
• On 401 Unauthorized: do not retry. Report "API key missing or invalid — check BOOKSEARCH_API_KEY env var" and stop.
• Send X-API-Key exactly once. Multi-valued headers are rejected.

Marketplace domains

At this time only two marketplaces are populated with data: the United States (domainId=1) and France (domainId=4). Additional marketplaces are planned but not yet available.

Map natural-language marketplace references (e.g. "the US store", "Amazon.com", "amazon francia", "Amazon.fr") to domainId using this table:

domainId	locale	country	name
1	com	US	United States
4	fr	FR	France

The validator technically accepts domainId 1–12, but only 1 (US) and 4 (FR) return data right now. If the user asks for any other marketplace (UK, Germany, Italy, Spain, Canada, Japan, etc.), tell them it is not currently supported — coming soon. Do not invent domain IDs.

Request schema

All fields are optional except domainId. Enums accept either the string name (e.g. "Weekly") or the integer value.

Required

Field	Type	Constraint
domainId	int	US (1) or FR (4) — the only marketplaces with data (validator allows 1–12).

BSR filters

Field	Type	Default	Notes
bsrType	enum	Weekly	Historical(-1), Current(0), Weekly(7), Days30(8), Days90(9), Days180(10), Days365(11)
bsrMin	int?	1	≥ 1
bsrMax	int?	100000	≥ 1, bsrMin ≤ bsrMax
bsrYear	short?	null	2000–(current year + 1). Required together with bsrMonth. Use only with bsrType=Historical.
bsrMonth	short?	null	1–12. Required together with bsrYear.

Product filters

Field	Type	Default	Notes
bindingType	enum?	null (all)	All, Paperback, Hardcover
publisherType	enum?	All	All, SelfPublishersOnly, PublishersOnly
interiorType	enum?	BlackWhite	BlackWhite, FullColor
vatType	enum?	Reduced	Reduced, Standard
includePreOrders	bool?	false	—

Quality filters

Field	Type	Constraint
ratingMin	double?	0.0–5.0, ratingMin ≤ ratingMax
ratingMax	double?	0.0–5.0
reviewsMin	int?	≥ 0, reviewsMin ≤ reviewsMax
reviewsMax	int?	≥ 0

Economic filters

Field	Type	Notes
royaltyMin	decimal?	In currency units, not cents. min ≤ max.
royaltyMax	decimal?	—
monthsSincePublicationMin	int?	min ≤ max
monthsSincePublicationMax	int?	—

Discovery

Field	Type	Default	Constraint
includeKeywords	string[]	null	≤ 25 items, each ≤ 100 chars, non-empty. Each element is matched as a literal contiguous substring (case-insensitive) against title, publisher and authors. Multiple elements are combined with OR. Pass multi-word phrases as a single element (["small business taxes"]), NOT as separate tokens (["small","business","taxes"]) — the latter would match any book containing just one of those words.
excludeKeywords	string[]	null	≤ 25 items, each ≤ 100 chars, non-empty. Same matching semantics as includeKeywords: each element is a literal contiguous substring; books matching any element on title, publisher or authors are excluded.
categoryIds	long[]	null	≤ 100 items, each > 0 (Amazon BrowseNode IDs). Subtree-expanded: passing a non-leaf node (e.g. depth-2 "Quick & Easy", catId=17) returns every book tagged with any descendant leaf — you do not need to enumerate leaves yourself. Pass any node from /categories, /categories/search, /categories/children, or /categories/ancestors. Mixing leaves and parents in one call is allowed (logical OR across the union of the expanded sets). Stale / unknown catIds collapse to no overlap and are silently dropped, not an error.
excludeFiction	bool?	true	When true (default), filters out fiction books — i.e. books whose categories all roll up to depth-2 ancestors flagged as fiction (Literature & Fiction, Romance, Mystery, Sci-Fi, Children's Books, Teen/YA, etc.) under the local Books root for the requested marketplace. A book is kept if at least one of its categories has a depth-2 ancestor flagged as non-fiction. Set false to include fiction. Auto-disabled when categoryIds is non-empty: explicit category intent overrides the fiction filter, otherwise passing a fiction category with the default would silently return zero results.

Pagination

Field	Type	Default	Range
limit	int?	100	1–300
offset	int?	0	0–100000

Workflow

1. Marketplace — Identify domainId from intent using the marketplace table. If ambiguous (e.g. "Amazon"), ask which country.
2. Translate — Map every natural-language filter to its schema field. Don't guess enum values; use the table. Note: by default fiction is excluded (excludeFiction=true). If the user asks for fiction (e.g. "romance", "mystery novels", "show me fiction too") or a mixed catalog, set excludeFiction: false explicitly. Most KDP/low-content niche queries are non-fiction so the default is usually correct.
3. Pagination — Default to limit: 50. Raise to 100–300 only if the user explicitly wants many results. Start with offset: 0.
4. Send — POST the JSON body. Inspect the status code first.
5. Paginate if needed — If returnedCount == limit, more results likely exist. Offer to fetch the next page with offset += limit.
6. Present — Surface title, asin, bsr, sales/revenue estimates, and a clickable cover URL (see response notes).

Example request

json

{
  "domainId": 4,
  "bsrType": "Days90",
  "bsrMin": 1,
  "bsrMax": 50000,
  "bindingType": "Paperback",
  "publisherType": "SelfPublishersOnly",
  "ratingMin": 4.0,
  "reviewsMin": 10,
  "interiorType": "BlackWhite",
  "vatType": "Reduced",
  "royaltyMin": 2.50,
  "royaltyMax": 15.00,
  "monthsSincePublicationMax": 24,
  "includePreOrders": false,
  "includeKeywords": ["journal", "notebook"],
  "excludeKeywords": ["coloring"],
  "categoryIds": [266162, 3248921],
  "excludeFiction": false,
  "limit": 50,
  "offset": 0
}

Example cURL

bash

curl -X POST "https://api.beyondbsr.com/api/v1/books/search" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  -d '{
    "domainId": 4,
    "bsrType": "Days90",
    "bsrMax": 50000,
    "bindingType": "Paperback",
    "publisherType": "SelfPublishersOnly",
    "ratingMin": 4.0,
    "limit": 50
  }'

Response schema

Envelope — BookSearchApiResponse

Field	Type	Notes
returnedCount	int	Items in this page. NOT a total-match count (no total exposed).
limit	int	Effective limit applied (capped at 300).
offset	int	Effective offset applied.
results	array	BookSearchResultDto[]. Empty if no match.

Result item — BookSearchResultDto (most relevant fields)

Field	Type	Notes
id	long	Internal book ID.
asin	string	10-char Amazon ASIN.
title	string	Full title.
authors	string?	Comma-separated, ordered by display_order.
publicationDate	datetime?	Nullable.
publisher	string?	Manufacturer/publisher name.
coverImageFilename	string?	Build URL: https://m.media-amazon.com/images/I/{filename}.
imageFilenames	string[]	All carousel images (same URL pattern).
rating	double	0.0–5.0.
reviews	int	Total reviews.
bsr	int	The column matching the requested bsrType — i.e. the value filtered/sorted on.
bsrCurrent	int?	Latest snapshot BSR, regardless of bsrType.
avgBsr7d	int?	Always populated.
avgBsr30d	int?	Always populated.
avgBsr90d	int?	Always populated.
avgBsr180d	int?	Always populated.
avgBsr365d	int?	Always populated.
pageCount	int?	—
priceCents	int?	List price (MSRP) in cents.
dailyEstimate	decimal	Estimated copies/day from BSR model.
weeklyEstimate	decimal	Estimated copies/week.
monthlyEstimate	decimal	Estimated copies/month.
quarterlyEstimate	decimal	Copies/quarter (needs ≥ 13 weeks of data).
royalty*Cents	int?	Per-copy royalty in cents. 4 combinations: B/W or Color × Reduced or Standard VAT.
*Revenue*Cents	long?	Derived = estimate × royalty. 16 fields total: {daily,weekly,monthly,quarterly} × {Black,Color} × {Reduced,Standard}.
binding	string?	Localised label (e.g. "Paperback", "Hardcover", "Non-standard").
dimensions	string?	Formatted, prefixed by binding. Example: "Paperback: 152 x 8 x 229 mm".
trim/spineWidthMm	int?	Trim/spine measurements.
categories	long[]	Raw leaf Amazon cat_ids the book is tagged with (verbatim from the database). Preserves original tag order. May be empty for books still being enriched.
categoryPaths	Array<Array<{catId:long,name:string,depth:int}>>	One inner array per entry in categories, each is the full root → leaf ancestor chain sorted by depth ascending. Use this to aggregate / group books by macro or sub category in a single round-trip without calling /categories/ancestors per leaf.
subcategoryRanks	Array<{catId:long,rank:int,name:string}>	Per-category Best Sellers Rank of the book inside each subcategory it is listed in (Amazon's "#1 in " data). catId is the Amazon browse node, rank is the position within that node, name is the localised category label. Ordered as returned by Amazon (best/most-specific first). May be empty [] for books not yet enriched. Distinct from the top-level bsr/bsrCurrent, which are the overall Books-store rank.
frequentlyBoughtTogether	string[]	ASINs of products Amazon surfaces as frequently bought together with this book. Use for competitor / cross-sell discovery (feed each ASIN back into bsr-history or a includeKeywords/asin-targeted search). May be empty []. Not every book has this data — populated for a subset of titles.

Important caveats

• All royalty and revenue fields are in cents — divide by 100 before showing currency.
• bsr ≠ bsrCurrent. bsr is whatever column was chosen by bsrType; bsrCurrent is always the latest snapshot.
• In bsrType=Historical mode, the avgBsrXd averages come from the current snapshot table while bsr itself is the historical month value — there is a documented temporal asymmetry inside the same response. Mention this if the user is doing a strict historical analysis.
• categoryPaths.length === categories.length for a healthy dataset. If a leaf cat_id has been deleted upstream after the book was indexed, the corresponding inner array is silently dropped (never null) — so categoryPaths.length may be ≤ categories.length. The categories array always reflects the original tag set.
• Both categories and categoryPaths may be empty arrays [] (never null) for books still being enriched or whose taxonomy snapshot hasn't propagated yet. Aggregation code must skip these books rather than fail on missing chains.

Aggregating results by category

Each categoryPaths inner array is sorted by depth ascending. The taxonomy under the Books root is consistent across marketplaces (only the labels are localised):

Depth	Role	US example	IT example
0	Books root	Books	Libri
1	Container shell	Subjects	Categorie
2	Top-level subject ("macro")	Self-Help, Cookbooks, Food & Wine, Crafts, Hobbies & Home	Cucina, casa e giardinaggio
3	Sub-category	Crafts & Hobbies, Christian Books & Bibles	—
4-5	Niche / micro-niche (KDP-relevant)	Coloring Books for Grown-Ups, Bible Study & Reference	—

To produce a market-opportunity report, group on the catId at the desired depth, not the name (names are locale-dependent; catId is stable). For KDP niche research the interesting depths are 3 and 4: depth 2 is usually too broad (e.g. "Crafts & Hobbies" alone covers thousands of books), while depth 3-4 isolates real nicchie ("Coloring Books for Grown-Ups", "Word Search", "Christian Living").

Pattern — nested macro → sub-niche histogram with revenue rollup, from one search response:

js

// macro (depth=2) -> { name, books, subniches: Map<catId, { name, books, monthlyRevCents }> }
const report = new Map();

for (const book of response.results) {
  const seenMacros  = new Set();   // dedupe within the same book
  const seenNiches  = new Set();

  for (const chain of book.categoryPaths) {        // may be [] for un-enriched books
    const macro = chain.find(n => n.depth === 2);
    const niche = chain.find(n => n.depth === 3) ?? chain.find(n => n.depth === 4);
    if (!macro) continue;

    if (!seenMacros.has(macro.catId)) {
      seenMacros.add(macro.catId);
      const m = report.get(macro.catId) ?? { name: macro.name, books: 0, subniches: new Map() };
      m.books++;
      report.set(macro.catId, m);
    }
    if (niche && !seenNiches.has(niche.catId)) {
      seenNiches.add(niche.catId);
      const m = report.get(macro.catId);
      const n = m.subniches.get(niche.catId) ?? { name: niche.name, books: 0, monthlyRevCents: 0 };
      n.books++;
      // pick whichever revenue field matches the user's interior/VAT context
      n.monthlyRevCents += book.monthlyRevenueBlackReducedVatCents ?? 0;
      m.subniches.set(niche.catId, n);
    }
  }
}

Sample fragment of a result with two categories (US, depth-1 is always Subjects — depth-2 is the macro):

json

{
  "asin": "1234567890",
  "title": "Quick Weeknight Dinners",
  "categories": [4259, 9876],
  "categoryPaths": [
    [
      { "catId": 283155, "name": "Books",                "depth": 0 },
      { "catId": 1000,   "name": "Subjects",             "depth": 1 },
      { "catId": 6,      "name": "Cookbooks, Food & Wine","depth": 2 },
      { "catId": 17,     "name": "Quick & Easy",         "depth": 3 },
      { "catId": 4259,   "name": "General",              "depth": 4 }
    ],
    [
      { "catId": 283155, "name": "Books",                       "depth": 0 },
      { "catId": 1000,   "name": "Subjects",                    "depth": 1 },
      { "catId": 10,     "name": "Health, Fitness & Dieting",   "depth": 2 },
      { "catId": 9876,   "name": "Diet & Weight Loss",          "depth": 3 }
    ]
  ]
}

One-shot aggregation tip. When the goal is a single histogram/report (as opposed to interactive paging), call POST /books/search with limit=300 (the max). A 300-result response is ~850 KB and returns in ~200-350 ms in production — almost always cheaper than paginating. Only fall back to paged fetches if more than 300 books matter for the report (rare for niche analysis).

BSR History endpoint

Single-ASIN BSR timeline. Returns raw snapshots from the time-series store, ordered ascending by recordedAt.

text

GET https://api.beyondbsr.com/api/v1/books/{domainId}/{asin}/bsr-history?days={1..365}
X-API-Key: $BOOKSEARCH_API_KEY
Accept: application/json

When to use

• The user has a specific ASIN and wants its BSR over time (chart, drill-down, sanity-check the search-time avgBsrXd averages).
• The user wants to verify a book's recent rank trajectory (e.g. "is it gaining or losing visibility?").

If the user has filter criteria but no specific ASIN, use POST /search first, then call this endpoint per ASIN of interest.

Path & query parameters

Param	In	Type	Required	Constraint
domainId	path	int	yes	US (1) or FR (4) — see Marketplace domains table (validator allows 1–12).
asin	path	string	yes	Exactly 10 chars, regex ^[A-Z0-9]{10}$ (uppercase letters / digits only).
days	query	int?	no	1–365. Default 365. Window is [now - days, now] UTC.

Example request

text

GET /api/v1/books/1/1635864348/bsr-history?days=90
X-API-Key: $BOOKSEARCH_API_KEY
Accept: application/json

Example cURL

bash

curl -X GET "https://api.beyondbsr.com/api/v1/books/1/1635864348/bsr-history?days=90" \
  -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  -H "Accept: application/json"

Response schema — BookBsrHistoryApiResponse

Field	Type	Notes
asin	string	Echoed from request.
domainId	int	Echoed from request.
fromUtc	datetime	Window start (now - days), UTC.
toUtc	datetime	Window end (now), UTC.
pointCount	int	Number of BSR snapshots in points.
points	array	BsrPointDto[] ordered ascending by recordedAt.

BsrPointDto:

Field	Type	Notes
recordedAt	datetime	UTC timestamp of the snapshot.
bestSellersRank	int?	BSR at that timestamp. May be null if Keepa returned no rank.

Example body:

json

{
  "asin": "1635864348",
  "domainId": 1,
  "fromUtc": "2026-01-27T00:00:00Z",
  "toUtc": "2026-04-27T00:00:00Z",
  "pointCount": 412,
  "points": [
    { "recordedAt": "2026-01-27T03:14:00Z", "bestSellersRank": 1234 },
    { "recordedAt": "2026-01-27T15:02:00Z", "bestSellersRank": 1218 }
  ]
}

Status codes (BSR history specific)

Code	Meaning	Notes
200	OK	pointCount may be 0 if no snapshots exist in the window.
400	Validation failed	ValidationProblemDetails. Common causes: days out of range, asin wrong format, domainId out of [1,12].
404	ASIN not found for that domain	ProblemDetails JSON ({title:"Not Found",status:404,...}). The book is not tracked in BeyondBSR for this marketplace. Tell the user — do not retry with the same pair.
401 / 429 / 500	See generic table below.

Caveats

• Granularity is raw: Keepa snapshots arrive 1–4× per day on actively-tracked books. A 365-day window typically yields 365–1460 points. No daily aggregation is applied.
• The endpoint returns only (recordedAt, bestSellersRank). Use POST /search if you also need rating/review/price data.
• ASIN is case-sensitive — must be uppercase. 1635864348 (all digits) is valid.
• Default 365 days is the cap. Longer histories are not exposed; do not retry with days > 365.

Categories endpoints

The four endpoints under /api/v1/categories expose the Amazon taxonomy (browse nodes) BeyondBSR has ingested per marketplace. They share the same API-key auth, rate limit (api-key policy), and domainId semantics as book search. All four are GET, JSON out, no request body.

Use cases

• Resolve a name → catId to pass into POST /books/search categoryIds. Example: user asks for "manga" books on US → call /categories/search?domainId=1&q=manga to get candidate cat_ids, then feed the chosen ones into categoryIds.
• Top-level book categories of a marketplace (e.g. "list the main Books categories on Amazon.fr"): GET /categories?domainId=4&depth=2.
• Walk down the tree from a known node (e.g. "what's under Cookbooks?"): GET /categories/children?domainId=1&catId=6.
• Walk up the tree / breadcrumb for a leaf node (e.g. "where does cat 4142740011 sit?"): GET /categories/ancestors?domainId=1&catId=4142740011 → returns root → … → node, ordered by depth.

Shared response object — CategoryBrowseNodeDto

Field	Type	Notes
catId	long	Amazon browse node ID. This is the value to pass into categoryIds in book search.
parentCatId	long?	Parent's catId. null for roots.
rootCatId	long	Top-level ancestor's catId (e.g. the Books root for the marketplace).
name	string	Localised name in the marketplace's language.
contextFreeName	string?	Name without parent context (Keepa-provided). May be null.
depth	int	0 = root. Top-level book categories are typically depth 2 (root → Categorie → top node).
isFiction	bool	Internal flag used by excludeFiction in book search. Only meaningful at depth=2 under Books root.
productCount	int?	Approximate number of products in that node (Keepa-reported). May be null.

1. List categories at a depth (top-level Books browser)

text

GET /api/v1/categories?domainId={..}&depth={0..5}&includeFiction={true|false}

Param	Type	Default	Notes
domainId	int	—	Required. Marketplace ID (1-12, but only 1 US and 4 FR return data).
depth	int?	2	Hierarchy level. 0 = root. 2 = top-level book categories ("Self-Help", "Cookbooks…", etc.). Allowed 0-5.
includeFiction	bool?	false	Whether to include nodes flagged as fiction (Literature & Fiction, Romance, Sci-Fi, Children's Books, Teen/YA, Comics, etc.).

Filters applied automatically (do not appear in params): only browse nodes (isBrowseNode=true), and only nodes whose root is the Books root of the marketplace — i.e. non-book trees (toys, electronics) are excluded. Use this endpoint to enumerate the canonical KDP-relevant taxonomy.

Order: productCount DESC, then name ASC.

Response envelope — CategoriesApiResponse:

Field	Type	Notes
domainId	int	Echo.
depth	int	Echo (resolved default if omitted).
returnedCount	int	Number of items in results.
results	array	CategoryBrowseNodeDto[].

2. Direct children of a category

text

GET /api/v1/categories/children?domainId={..}&catId={..}

Param	Type	Notes
domainId	int	Required.
catId	long	Required. Parent category's Amazon browse node ID.

No implicit filters. Returns ALL active direct children of the parent — including non-browse nodes and fiction nodes. Use it for true tree navigation regardless of book/non-book context.

Order: productCount DESC, then name ASC.

Returns 404 if catId does not exist for the given marketplace. Do not retry on 404.

Response envelope — CategoryChildrenApiResponse:

Field	Type	Notes
domainId	int	Echo.
parentCatId	long	Echo of the input catId.
returnedCount	int
results	array	CategoryBrowseNodeDto[].

3. Search categories by name

text

GET /api/v1/categories/search?domainId={..}&q={..}&limit={1..200}

Param	Type	Default	Notes
domainId	int	—	Required.
q	string	—	Required. Case-insensitive substring match on name. Min 3 chars, max 100. Wildcards (%, _, \) are treated as literals (escaped server-side).
limit	int?	50	1-200. Pushed down to SQL.

No implicit filters. Searches across the ENTIRE category tree of the marketplace (not just Books) — so a query like "Sports" on Amazon.com will surface both "Sports & Outdoors" (under Books) and the toy/apparel "Sports" nodes. The agent should filter client-side by rootCatId if the user only wants book categories.

Order: productCount DESC, then depth ASC, then name ASC.

Response envelope — CategorySearchApiResponse:

Field	Type	Notes
domainId	int	Echo.
query	string	Echo of q.
limit	int	Effective limit applied.
returnedCount	int
results	array	CategoryBrowseNodeDto[].

Tip: if the user-typed term is broad (e.g. "fiction") and the default limit=50 truncates likely candidates, raise limit to 200. If still not enough, refine the term or use /categories?depth=2 instead.

4. Ancestors / breadcrumb of a category

text

GET /api/v1/categories/ancestors?domainId={..}&catId={..}

Param	Type	Notes
domainId	int	Required.
catId	long	Required. Category whose breadcrumb to retrieve.

Returns the full ancestor chain including the node itself, ordered by depth ASC. No implicit filters (intermediate non-browse / promotional nodes are included).

Returns 404 if catId does not exist for the marketplace.

Response envelope — CategoryAncestorsApiResponse:

Field	Type	Notes
domainId	int	Echo.
catId	long	Echo.
returnedCount	int	Length of the chain (includes the requested node).
results	array	CategoryBrowseNodeDto[] from root (depth=0) to the node itself.

Example workflows

Resolve "manga" on Amazon.com then search books (replace <catId> with a candidate returned by step 1):

bash

# 1. find candidate cat_ids
curl -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  "https://api.beyondbsr.com/api/v1/categories/search?domainId=1&q=manga&limit=10"

# 2. inspect the breadcrumb of a candidate to confirm it's under Books
curl -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  "https://api.beyondbsr.com/api/v1/categories/ancestors?domainId=1&catId=<catId>"

# 3. drill down children if needed
curl -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  "https://api.beyondbsr.com/api/v1/categories/children?domainId=1&catId=<catId>"

# 4. plug the chosen cat_id(s) into book search
curl -X POST -H "X-API-Key: $BOOKSEARCH_API_KEY" -H "Content-Type: application/json" \
  -d '{"domainId":1,"categoryIds":[<catId>],"limit":50}' \
  "https://api.beyondbsr.com/api/v1/books/search"

List top-level Books categories on Amazon.com (non-fiction only, default):

bash

curl -H "X-API-Key: $BOOKSEARCH_API_KEY" \
  "https://api.beyondbsr.com/api/v1/categories?domainId=1&depth=2"

Status codes (categories endpoints)

Code	Meaning	Notes
200	OK	results may be empty (e.g. no children, no matches, marketplace not seeded).
400	Validation failed	ValidationProblemDetails. Common causes: domainId out of range, q < 3 chars, limit out of 1-200, depth out of 0-5.
401	Auth failed	Same handling as book search — stop, report misconfigured key.
404	catId not found for domainId	ProblemDetails JSON ({title:"Not Found",status:404,...}). Only on /children and /ancestors. Do not retry the same pair.
429	Rate limit	Honour Retry-After. Same key budget as book search (30 req/min).
500	Server error	Retry once, then escalate.

Caveats

• Read-only. No POST/PUT/DELETE on categories.
• catId vs internal id. The wire contract exposes only Amazon's catId (browse node ID). The internal database id is never surfaced and is not interchangeable.
• depth=2 ≠ "top-level under Books" universally. Most marketplaces seed Books root at depth=0 → "Categorie/Categories" at depth=1 → top nodes at depth=2. If /categories?depth=2 returns unexpectedly few rows for a marketplace, retry with depth=1.
• excludeFiction semantics propagate. A node's isFiction=true here is exactly what excludeFiction in book search rolls up on. If a user complains that a fiction sub-genre isn't being excluded, the agent can spot-check via /categories/ancestors?catId=… whether the depth-2 ancestor is flagged.
• Children endpoint includes non-browse nodes. Some Amazon nodes are promotional or grouping shells (isBrowseNode=false). They cannot be used as categoryIds filters in book search. Skip them or warn the user.

Status codes & error handling

Code	Meaning	Body	Agent action
200	OK (may be empty list)	BookSearchApiResponse	Parse results. Empty array = no matches, not an error.
400	Validation failed	ValidationProblemDetails (RFC 7807)	Read the errors map, fix the body, do not retry blindly. Surface the issue.
401	Auth failed	empty + WWW-Authenticate: ApiKey realm="BeyondBSR"	Stop. Report misconfigured BOOKSEARCH_API_KEY. Do not retry.
429	Rate limit exceeded	"Rate limit exceeded. Please try again later." + Retry-After header	Honour Retry-After. Back off. Do not hammer the endpoint.
500	Unhandled server error	ProblemDetails JSON	Retry once after a few seconds. If it persists, escalate to the user.

Example 400 body

json

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "DomainId": ["DomainId must be between 1 and 12."],
    "Limit": ["Limit must be between 1 and 300."]
  }
}

Sorting & pagination notes

• Default sort: ORDER BY <chosen BSR column> ASC (lower BSR = better seller appears first).
• Historical mode (bsrType=Historical + bsrYear/bsrMonth): sorted by the historical monthly BSR rank ASC.
• Tie-breaker is non-deterministic — books with identical BSR may appear in different orders across page fetches. Warn the user if they need a perfectly stable ordering.
• No orderBy parameter is exposed.

Limits

• Rate limit: 30 requests/minute per API key. Shared across all callers using the same key.
• Body size: 128 KB max.
• Page size: 300 results max per request (limit ≤ 300).
• Offset cap: 100,000 (deep pagination beyond this is not supported — refine filters instead).