ISBNdb

ISBNdb is the world's largest book database REST API providing access to metadata for over 110 million books and publications. Search by ISBN (ISBN-10 or ISBN-13), title, author, publisher, or subject to retrieve up to 19 data points per book including cover images, publication dates, descriptions, and real-time pricing. The API supports bulk lookups of up to 1,000 ISBNs per request on eligible plans.

ISBNdb publishes 8 APIs on the APIs.io network, including Author API, Books API, Feed API, and 5 more. Tagged areas include Books, ISBN, Publishing, Metadata, and Library.

The ISBNdb catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

ISBNdb’s developer surface includes authentication, documentation, pricing, engineering blog, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub

43.1/100 developing ▬ flat Agent 29/100 agent aware Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

AccessPaidSelf serve

8 APIs

BooksISBNPublishingMetadataLibraryBibliography

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 43.1/100 · developing

Contract Quality 12.0 / 21

Developer Ergonomics 4.9 / 17

Access Clarity 8.5 / 17

Operational Transparency 3.5 / 11

Contract Governance 1.0 / 10

Discoverability 6.3 / 9

Regulatory Posture 4.7 / 15

Agent readiness — 29/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Regulatory Posture applies to this provider. Its tags matched the Education & Research regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/isbndb: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 8

Individual APIs this provider publishes, each with its own machine-readable definition.

Rate Limits 1

Documented rate limits and quota policies.

Isbndb Rate Limits

10 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

Book

25 properties

JSON SCHEMA

Examples 4

Example request and response payloads for these APIs.

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 2

SDKs, sample code, and the tooling you integrate with

PostmanCollection

PostmanCollection

PostmanWorkspace

PostmanWorkspace

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

Plans

Plans

FinOps

FinOps

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Source (apis.yml)

aid: isbndb
name: ISBNdb
description: ISBNdb is the world's largest book database REST API providing access to metadata for over 110 million books
  and publications. Search by ISBN (ISBN-10 or ISBN-13), title, author, publisher, or subject to retrieve up to 19 data points
  per book including cover images, publication dates, descriptions, and real-time pricing. The API supports bulk lookups of
  up to 1,000 ISBNs per request on eligible plans.
accessModel:
  pricing: paid
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Paid · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/isbndb.png
url: https://raw.githubusercontent.com/api-evangelist/isbndb/refs/heads/main/apis.yml
created: '2026-06-13'
modified: '2026-06-13'
specificationVersion: '0.23'
tags:
- Books
- ISBN
- Publishing
- Metadata
- Library
- Bibliography
apis:
- aid: isbndb:isbndb-author-api
  name: ISBNdb Author API
  description: Author endpoints
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Author
  properties:
  - type: OpenAPI
    url: openapi/isbndb-author-api-openapi.yml
  - type: Collection
    url: collections/isbndb-author-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-books-api
  name: ISBNdb Books API
  description: Book endpoints
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Books
  properties:
  - type: OpenAPI
    url: openapi/isbndb-books-api-openapi.yml
  - type: Collection
    url: collections/isbndb-books-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-feed-api
  name: ISBNdb Feed API
  description: Feed endpoints for incremental sync
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Feed
  properties:
  - type: OpenAPI
    url: openapi/isbndb-feed-api-openapi.yml
  - type: Collection
    url: collections/isbndb-feed-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-key-api
  name: ISBNdb Key API
  description: API key management
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Key
  properties:
  - type: OpenAPI
    url: openapi/isbndb-key-api-openapi.yml
  - type: Collection
    url: collections/isbndb-key-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-publisher-api
  name: ISBNdb Publisher API
  description: Publisher endpoints
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Publishers
  tags_raw:
  - Publisher
  properties:
  - type: OpenAPI
    url: openapi/isbndb-publisher-api-openapi.yml
  - type: Collection
    url: collections/isbndb-publisher-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-search-api
  name: ISBNdb Search API
  description: Legacy search endpoints (deprecated)
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Search
  properties:
  - type: OpenAPI
    url: openapi/isbndb-search-api-openapi.yml
  - type: Collection
    url: collections/isbndb-search-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-stats-api
  name: ISBNdb Stats API
  description: Database statistics
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Stats
  properties:
  - type: OpenAPI
    url: openapi/isbndb-stats-api-openapi.yml
  - type: Collection
    url: collections/isbndb-stats-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
- aid: isbndb:isbndb-subject-api
  name: ISBNdb Subject API
  description: Subject endpoints
  humanURL: https://isbndb.com/api-documentation
  baseURL: https://api2.isbndb.com
  tags:
  - Subject
  properties:
  - type: OpenAPI
    url: openapi/isbndb-subject-api-openapi.yml
  - type: Collection
    url: collections/isbndb-subject-api.postman_collection.json
  - type: Documentation
    url: https://isbndb.com/api-documentation
  - type: Pricing
    url: https://isbndb.com/isbn-database
common:
- type: PostmanCollection
  url: https://www.postman.com/api-evangelist/isbndb/collection/86oo60r/isbndb-api
- type: PostmanWorkspace
  url: https://www.postman.com/api-evangelist/isbndb
- type: AgenticAccess
  url: agentic-access/isbndb-agentic-access.yml
- type: DomainSecurity
  url: security/isbndb-domain-security.yml
- type: Authentication
  url: authentication/isbndb-authentication.yml
- type: Website
  url: https://isbndb.com
- type: Documentation
  url: https://isbndb.com/api-documentation
- type: Pricing
  url: https://isbndb.com/isbn-database
- type: Blog
  url: https://isbndb.com/blog/
- type: X
  url: https://x.com/ISBNdb_com
- type: Plans
  url: plans/isbndb-plans-pricing.yml
- type: RateLimits
  url: rate-limits/isbndb-rate-limits.yml
- type: FinOps
  url: finops/isbndb-finops.yml
X-Provenance:
- date: '2026-08-13'
  surface: OpenAPI
  url: https://api2.isbndb.com/doc.json
  http_status: 200
  action: re-harvested
  note: 'ISBNdb wrote in asking us to update the Postman collection: it documented a dewey_decimal field they do not have,
    and its sample responses were generated placeholders. Both correct. Re-harvested their live spec, which their own docs
    link as the specification of record. Their current spec and the copy we held are BOTH labelled version 2.7.0 with the
    same 16 paths, but theirs has dropped dewey_decimal and added 7 filter schemas — the version string did not change, so
    nothing downstream could detect the revision. dewey_decimal removed from the OpenAPIs, collections, JSON Schema, JSON-LD
    context, vocabulary and examples. Placeholder responses persist because their spec carries exactly one `example` and zero
    `examples`; that fix belongs upstream.'
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com