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 support@beyondbsr.com. 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:

domainIdlocalecountryname1comUSUnited States4frFRFrance

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#

FieldTypeConstraintdomainIdintUS ( 1) or FR ( 4) — the only marketplaces with data (validator allows 1–12).

BSR filters#

FieldTypeDefaultNotesbsrTypeenumWeekly``Historical(-1), Current(0), Weekly(7), Days30(8), Days90(9), Days180(10), Days365(11)``bsrMinint?1≥ 1bsrMaxint?100000≥ 1, bsrMin ≤ bsrMax``bsrYearshort?null2000–(current year + 1). Required together with bsrMonth. Use only with bsrType=Historical.bsrMonthshort?null1–12. Required together with bsrYear.

Product filters#

FieldTypeDefaultNotesbindingTypeenum?null (all)All, Paperback, Hardcover``publisherTypeenum?All``All, SelfPublishersOnly, PublishersOnly``interiorTypeenum?BlackWhite``BlackWhite, FullColor``vatTypeenum?Reduced``Reduced, Standard``includePreOrdersbool?false—

Quality filters#

FieldTypeConstraintratingMindouble?0.0–5.0, ratingMin ≤ ratingMax``ratingMaxdouble?0.0–5.0reviewsMinint?≥ 0, reviewsMin ≤ reviewsMax``reviewsMaxint?≥ 0

Economic filters#

FieldTypeNotesroyaltyMindecimal?In currency units, not cents. min ≤ max.royaltyMaxdecimal?—monthsSincePublicationMinint?min ≤ max``monthsSincePublicationMaxint?—

Discovery#

FieldTypeDefaultConstraintincludeKeywordsstring[]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.excludeKeywordsstring[]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.categoryIdslong[]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 catId s collapse to no overlap and are silently dropped, not an error.excludeFictionbool?trueWhen 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#

FieldTypeDefaultRangelimitint?1001–300offsetint?00–100000

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#

FieldTypeNotesreturnedCountintItems in this page. NOT a total-match count (no total exposed).limitintEffective limit applied (capped at 300).offsetintEffective offset applied.resultsarrayBookSearchResultDto[]. Empty if no match.

Result item — BookSearchResultDto (most relevant fields)#

FieldTypeNotesidlongInternal book ID.asinstring10-char Amazon ASIN.titlestringFull title.authorsstring?Comma-separated, ordered by display_order.publicationDatedatetime?Nullable.publisherstring?Manufacturer/publisher name.coverImageFilenamestring?Build URL: https://m.media-amazon.com/images/I/{filename}.imageFilenamesstring[]All carousel images (same URL pattern).ratingdouble0.0–5.0.reviewsintTotal reviews.bsrintThe column matching the requested bsrType — i.e. the value filtered/sorted on.bsrCurrentint?Latest snapshot BSR, regardless of bsrType.avgBsr7dint?Always populated.avgBsr30dint?Always populated.avgBsr90dint?Always populated.avgBsr180dint?Always populated.avgBsr365dint?Always populated.pageCountint?—priceCentsint?List price (MSRP) in cents.dailyEstimatedecimalEstimated copies/day from BSR model.weeklyEstimatedecimalEstimated copies/week.monthlyEstimatedecimalEstimated copies/month.quarterlyEstimatedecimalCopies/quarter (needs ≥ 13 weeks of data).royalty*Centsint?Per-copy royalty in cents. 4 combinations: B/W or Color × Reduced or Standard VAT.*Revenue*Centslong?Derived = estimate × royalty. 16 fields total: {daily,weekly,monthly,quarterly} × {Black,Color} × {Reduced,Standard}.bindingstring?Localised label (e.g. "Paperback", "Hardcover", "Non-standard").dimensionsstring?Formatted, prefixed by binding. Example: "Paperback: 152 x 8 x 229 mm".trim/spineWidthMmint?Trim/spine measurements.categorieslong[]Raw leaf Amazon cat_id s 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):

DepthRoleUS exampleIT example0Books rootBooks``Libri1Container shellSubjects``Categorie2Top-level subject ("macro")Self-Help, Cookbooks, Food & Wine, Crafts, Hobbies & Home``Cucina, casa e giardinaggio3Sub-categoryCrafts & Hobbies, Christian Books & Bibles—4-5Niche / 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#

ParamInTypeRequiredConstraintdomainIdpathintyesUS ( 1) or FR ( 4) — see Marketplace domains table (validator allows 1–12).asinpathstringyesExactly 10 chars, regex ^[A-Z0-9]{10}$ (uppercase letters / digits only).daysqueryint?no1–365. 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#

FieldTypeNotesasinstringEchoed from request.domainIdintEchoed from request.fromUtcdatetimeWindow start ( now - days), UTC.toUtcdatetimeWindow end ( now), UTC.pointCountintNumber of BSR snapshots in points.pointsarrayBsrPointDto[] ordered ascending by recordedAt.

BsrPointDto:

FieldTypeNotesrecordedAtdatetimeUTC timestamp of the snapshot.bestSellersRankint?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)#

CodeMeaningNotes200OKpointCount may be 0 if no snapshots exist in the window.400Validation failedValidationProblemDetails. Common causes: days out of range, asin wrong format, domainId out of [1,12].404ASIN not found for that domainProblemDetails 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 / 500See 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#

FieldTypeNotescatIdlongAmazon browse node ID. This is the value to pass into categoryIds in book search.parentCatIdlong?Parent's catId. null for roots.rootCatIdlongTop-level ancestor's catId (e.g. the Books root for the marketplace).namestringLocalised name in the marketplace's language.contextFreeNamestring?Name without parent context (Keepa-provided). May be null.depthint0 = root. Top-level book categories are typically depth 2 (root → Categorie → top node).isFictionboolInternal flag used by excludeFiction in book search. Only meaningful at depth=2 under Books root.productCountint?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}

ParamTypeDefaultNotesdomainIdint—Required. Marketplace ID (1-12, but only 1 US and 4 FR return data).depthint?2Hierarchy level. 0 = root. 2 = top-level book categories ("Self-Help", "Cookbooks…", etc.). Allowed 0-5.includeFictionbool?falseWhether 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:

FieldTypeNotesdomainIdintEcho.depthintEcho (resolved default if omitted).returnedCountintNumber of items in results.resultsarrayCategoryBrowseNodeDto[].

2. Direct children of a category#

text

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

ParamTypeNotesdomainIdintRequired.catIdlongRequired. 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:

FieldTypeNotesdomainIdintEcho.parentCatIdlongEcho of the input catId.returnedCountintresultsarrayCategoryBrowseNodeDto[].

3. Search categories by name#

text

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

ParamTypeDefaultNotesdomainIdint—Required.qstring—Required. Case-insensitive substring match on name. Min 3 chars, max 100. Wildcards ( %, _, \) are treated as literals (escaped server-side).limitint?501-200. 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:

FieldTypeNotesdomainIdintEcho.querystringEcho of q.limitintEffective limit applied.returnedCountintresultsarrayCategoryBrowseNodeDto[].

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={..}

ParamTypeNotesdomainIdintRequired.catIdlongRequired. 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:

FieldTypeNotesdomainIdintEcho.catIdlongEcho.returnedCountintLength of the chain (includes the requested node).resultsarrayCategoryBrowseNodeDto[] 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)#

CodeMeaningNotes200OKresults may be empty (e.g. no children, no matches, marketplace not seeded).400Validation failedValidationProblemDetails. Common causes: domainId out of range, q < 3 chars, limit out of 1-200, depth out of 0-5.401Auth failedSame handling as book search — stop, report misconfigured key.404catId not found for domainId``ProblemDetails JSON ( {title:"Not Found",status:404,...}). Only on /children and /ancestors. Do not retry the same pair.429Rate limitHonour Retry-After. Same key budget as book search (30 req/min).500Server errorRetry 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#

CodeMeaningBodyAgent action200OK (may be empty list)BookSearchApiResponseParse results. Empty array = no matches, not an error.400Validation failedValidationProblemDetails (RFC 7807)Read the errors map, fix the body, do not retry blindly. Surface the issue.401Auth failedempty + WWW-Authenticate: ApiKey realm="BeyondBSR"Stop. Report misconfigured BOOKSEARCH_API_KEY. Do not retry.429Rate limit exceeded"Rate limit exceeded. Please try again later." + Retry-After headerHonour Retry-After. Back off. Do not hammer the endpoint.500Unhandled server errorProblemDetails JSONRetry 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).