ISBNdb
ISBNdb is a book metadata API platform founded in 2001, providing REST access to 114M+ books with up to 19 structured fields per record via tiered subscriptions, serving online booksellers, libraries, publishers, and book-related startups globally.
- Company typePrivate
- Founded2001
- HeadquartersFunchal, Portugal
- Headcount—
- GTM typeB2B
- OfferingSoftware
What ISBNdb does
ISBNdb is a book metadata API platform founded in 2001 and operated by Estelar Software Unipessoal LDA, a Portuguese single-member limited liability company headquartered in Funchal, Madeira. The company's core product is a REST API (hosted at api2.isbndb.com) providing structured access to a database of 114+ million books, searchable by ISBN, title, author, or publisher, with up to 19 standardized data fields per record (ISBN10/13, title, author, publication date, publisher, binding, pages, list price, cover image, language, edition, format, synopsis, subject, weight, dimensions). Data is aggregated from hundreds of libraries, publishers, and merchants worldwide with daily updates, and the company describes ~70% of its records as unique relative to competing databases.
The platform is monetized through tiered subscriptions — Basic ($14.99/mo), Premium ($35.99/mo), Pro ($99.99/mo), Enterprise ($299.99/mo), and an annual-only Enterprise Pro plan at $4,999/yr — with a discounted $7.50/mo Academic/Non-Profit tier and a 7-day free trial on Basic. A Shopify app (Book Data Importer) provides a no-code distribution channel for ecommerce bookstore operators, and a Book Recommendation Dataset & API targets AI/recommendation-system builders. Go-to-market is predominantly self-serve and product-led, with enterprise/custom plans sold via direct contact. Named customers are startups across book collection management, indie retail, textbook price comparison, book sharing, education compliance, and social reading — segments served horizontally rather than vertically.
ISBNdb has operated continuously for over two decades without external funding under disclosed, maintains multi-language API documentation (Python, Node.js, PHP, C#, Java) with an OpenAPI specification, and ships ongoing product updates (dashboard overhaul, instant plan upgrades, /feeds/books/updates feed, API domain consolidation, Enterprise Pro tier). The business is positioned as infrastructure for downstream book-related applications rather than a consumer-facing product.
ISBNdb firmographics
Firmographics- Name
- ISBNdb
- Legal name
- ESTELAR SOFTWARE UNIPESSOAL LDA
- Website
- https://isbndb.com
- Company type
- Private
- Founded year
- 2001
- Operating status
- Operating
- Short description
- ISBNdb is a book metadata API platform founded in 2001, providing REST access to 114M+ books with up to 19 structured fields per record via tiered subscriptions, serving online booksellers, libraries, publishers, and book-related startups globally.
- Ownership category
- akta.pro rank
ISBNdb industry classification
Industry- Product category
- Book Metadata API
- NAICS
- Software Publishers (5132), Software Publishers (513210), Web Search Portals, Libraries, Archives, and Other Information Services (5192)
- SIC
- Services-Prepackaged Software (7372)
- akta.pro primary industry
- Rights, ISBN & Publishing Administration Services (Identifiers, Metadata, Royalties) (MPAJAJAK)
- akta.pro secondary industry
- Library Collections & Cataloging Services (Acquisitions, Metadata, Circulation) (EDAEAGAE)
Keywords
Where ISBNdb is headquartered
LocationHeadquarters
- HQ city
- Funchal
- HQ country
- Portugal
- HQ region
- Europe
Offices1 record
Markets served
ISBNdb business model
Business model- GTM type
- B2B
- Offering type
- Software
- Cost components
- Technology or R&D, Infrastructure, Personnel, Marketing or Sales, Operations
Revenue model
- API Subscription Plans: Tiered subscription model (Basic, Premium, Pro, Enterprise) with monthly and annual billing options. Higher tiers offer increased daily searches, call rate limits, and bulk data capabilities. Revenue is recurring from active subscriptions.
- Academic/Non-Profit Discounts: Discounted Academic Plan at $7.50/month for verified academic institutions and non-profit organizations with 501(c)(3) status
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Subscription | Monthly | Basic Plan - 5,000 daily searches |
| Subscription | Monthly | Premium Plan - 15,000 daily searches |
| Subscription | Monthly | Pro Plan - 50,000 daily searches with real-time pricing |
| Subscription | Monthly | Enterprise Plan - 200,000 daily searches |
| Subscription | Annual | Enterprise Pro Plan - Annual only high-volume plan |
| Subscription | Monthly | Academic/Non-Profit Plan - $7.50/month |
Go-to-market motion2 records
Distribution channels3 records
Marketing channels5 records
ISBNdb product offering
Product offeringCore offering
ISBNdb provides a REST API for retrieving structured book metadata from a database of 114+ million books, searchable by ISBN, title, author, or publisher and returning up to 19 data fields per title. The platform is sold on tiered subscription plans (Basic through Enterprise Pro) starting at $14.99/month, with a dedicated Shopify app enabling bookstores to import book data into their stores and a specialized Book Recommendation Dataset & API for recommendation systems. The service does not sell physical books — it sells only bibliographic data.
Product overview
ISBNdb is a book metadata API platform with three primary offerings: (1) the core ISBNdb Book Database API providing access to 114+ million books via REST endpoints with up to 19 data points per title, (2) a dedicated Book Data Importer Shopify app enabling bookstore operators to bulk-import books into Shopify by ISBN scan or paste, and (3) a Book Recommendation Dataset & API tailored for building AI-powered book recommendation systems. The core API and the Shopify integration share the same underlying book database; the recommendation dataset is a specialized use-case variant of the same API.
Differentiator
Problem solved
Functional benefit
Brands
- ISBNdb Book Data Importer: A Shopify app that allows users to import book metadata into their Shopify store by entering ISBNs, pasting bulk ISBNs, or scanning physical books with a barcode scanner.
Companies that use ISBNdb
Customer profileNamed customers9 records
Segments4 records
Ideal customer profiles3 records
ISBNdb technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- Yes
- API docs
- API detail
Core technology
AI maturity
App detail
Integration1 record
AI capability4 records
Feature6 records
ISBNdb partnerships and signals
Strategic signalPartnerships
Five partnerships are on record, tiered minor.
- Waterside PressminorPublisher partner included in ISBNdb's publisher network. Publishers can connect their book product feeds directly with ISBNdb's distribution network to expand market reach and ensure accurate book representation across digital touchpoints.
- Aurora Metro BooksminorPublisher partner in ISBNdb's network enabling distribution of book metadata to ISBNdb's extensive client base including ecommerce businesses and book apps.
- BulgilhanminorPublisher partner allowing their book catalog to be represented in ISBNdb's database and distributed across the network of ISBNdb clients.
- Children Bilingual BooksminorPublisher partner specializing in bilingual children's books, integrated into ISBNdb's metadata distribution network.
- Whole PhonicsminorPublisher partner for educational/phonics materials, participating in ISBNdb's data distribution ecosystem.
Scale indicators8 records
Recent moves6 records
Expansion highlights5 records
ISBNdb competitors and assessment
Company assessmentDirect peers
- Bowker (ISBN Agency): Bowker is the official ISBN registry in the US and offers book metadata services including BooksInPrint. It is a direct competitor for authoritative bibliographic data and ISBN-linked metadata, with a long-standing position in the publishing supply chain.
- Open Library (Internet Archive): Open Library provides free bibliographic data and book metadata through its API. It is the most direct competitor to ISBNdb for developers needing book data, offering a similar API-first data model with no usage fees, putting price pressure on ISBNdb's lower tiers.
Emerging players
- StoryGraph: StoryGraph is a Goodreads alternative providing book tracking and reading statistics. Uses its own data infrastructure but targets the same reading-tracker use case that ISBNdb serves via integrations with Inset Books and Seekquel.
- LibraryThing: LibraryThing provides book cataloging services and APIs with social reading features. Comparable to ISBNdb in serving book catalogers and reading communities, though it is more consumer-facing and offers limited commercial/ecommerce use cases.
- BookScouter: BookScouter aggregates book buyback and pricing data for textbook resellers. Overlaps with ISBNdb's price-comparison use cases (CampusBooks) where real-time book pricing data is valuable, though narrower in scope.
Regional players
- Bookfinder.com: Bookfinder is a textbook and book price comparison engine operating in similar territory to CampusBooks (an ISBNdb customer). Comparable as a book discovery/pricing platform but does not offer metadata APIs directly.
Broad incumbents
- Goodreads (Amazon): Goodreads is the dominant consumer book catalog and reading tracker owned by Amazon. ISBNdb customers (Inset Books, Seekquel) explicitly position themselves as alternatives to Goodreads, indicating overlapping end-user segments and competitive pressure on reading app data needs.
- OCLC WorldCat: OCLC operates WorldCat, the world's largest library catalog aggregation with hundreds of millions of bibliographic records. Comparable to ISBNdb for library and institutional customers needing comprehensive book metadata, though OCLC focuses on the library market rather than ecommerce/developer segments.
- Google Books APIs: Google's book search platform offers free bibliographic metadata and covers/ preview data at massive scale. Comparable as a competing book data source for developers building book-related applications, though positioned as a free alternative rather than a paid API.
Others
- Stripe Atlas Companies / Product Hunt launches (book data startups): The broader book-tech startup ecosystem (e.g., Bookhead, Booklinker, Inset Books shown as ISBNdb customers) represents both demand-side customers and potential adjacent startups. Comparable as adjacent participants in the book metadata / book app ecosystem, though they are buyers of book data APIs rather than competitors.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat4 records
Key risks6 records
Key highlights7 records
Customer concentration
ISBNdb social profiles
Digital presenceISBNdb financial estimates
Financial estimateRevenue estimate
Valuation estimate
ISBNdb leadership team
Management profileNumber of profiles
ISBNdb funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
ISBNdb M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about ISBNdb
What does ISBNdb do?
ISBNdb provides a REST API for retrieving structured book metadata from a database of 114+ million books, searchable by ISBN, title, author, or publisher and returning up to 19 data fields per title. The platform is sold on tiered subscription plans (Basic through Enterprise Pro) starting at $14.99/month, with a dedicated Shopify app enabling bookstores to import book data into their stores and a specialized Book Recommendation Dataset & API for recommendation systems. The service does not sell physical books — it sells only bibliographic data.
Is ISBNdb a public or private company?
ISBNdb is a private company. It is classified as founder individual operated bootstrapped and is currently operating.
When was ISBNdb founded?
ISBNdb was founded in 2001.
Where is ISBNdb based?
ISBNdb is headquartered in Funchal, Portugal, in the Europe region.
How does ISBNdb make money?
Two revenue lines are on record. API Subscription Plans are the primary driver. The others are academic/Non-Profit Discounts.
Who are ISBNdb's main competitors?
Direct peers on record are Bowker (ISBN Agency) and Open Library (Internet Archive). Emerging players are StoryGraph, LibraryThing and BookScouter. Bookfinder.com is listed as a regional player. Broad incumbents are Goodreads (Amazon), OCLC WorldCat and Google Books APIs. Stripe Atlas Companies / Product Hunt launches (book data startups) is listed as an others.
Does ISBNdb have an API?
Yes. ISBNdb provides a REST API (API v2) accessible at https://api2.isbndb.com that allows developers to retrieve information about millions of books. Authentication uses an API key passed via HTTP Authorization header. The API supports GET requests for single book lookups by ISBN and POST requests for bulk retrieval of multiple books. Available endpoints include /book/{isbn}, /books, /authors, /publishers, /subjects, and a recently added /feeds/books/updates endpoint (Premium+). Plans range from 5,000 daily searches (Basic) to 200,000 daily searches (Enterprise), with call-per-second limits ranging from 1 to 10. Bulk data (up to 1,000 results per call) is available on Premium and higher plans. Code examples are provided for Python, Node.js, PHP, C# (.NET), and Java. OpenAPI specification is available at https://api2.isbndb.com/doc.json. Developer documentation is at isbndb.com/isbndb-api-documentation-v2.
What industry is ISBNdb in?
ISBNdb's product category is Book Metadata API. Its primary akta.pro industry code is MPAJAJAK, Rights, ISBN & Publishing Administration Services (Identifiers, Metadata, Royalties), with a secondary code of EDAEAGAE, Library Collections & Cataloging Services (Acquisitions, Metadata, Circulation). Its NAICS code is 5132 and its SIC code is 7372.