Fatcat

Fatcat is a versioned, user-editable open catalog of published research works maintained by the Internet Archive. It tracks bibliographic metadata, links papers to full-text copies, and preserves access to scholarly publications including journal articles, conference proceedings, and datasets across millions of research works.

Fatcat publishes 11 APIs on the APIs.io network, including auth API, changelog API, containers API, and 8 more. Tagged areas include Scholarly, Research, Academic, Open Access, and Bibliographic.

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

Fatcat’s developer surface includes authentication and 4 more developer resources.

🌐 Visit website 📡 Source on GitHub
33.1/100 thin ▬ flat Agent 26/100 agent aware Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0
AccessFreeSelf serve⚡ Free to try
1 APIs
ScholarlyResearchAcademicOpen AccessBibliographicPublicationsMetadataInternet Archive

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0
Composite quality — 33.1/100 · thin
Contract Quality 10.7 / 19
Developer Ergonomics 2.5 / 15
Access Clarity 4.3 / 15
Operational Transparency 2.1 / 10
Contract Governance 0.9 / 9
Discoverability 5.7 / 8
Regulatory Posture 3.1 / 15
Create-or-Update Ergonomics 0.0 / 10
Agent readiness — 26/100 · 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 8 / 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
Delegated User Identity 0 / 6
Protected Resource Metadata 0 / 5
Registration Without a Human 0 / 6
Agentic Commerce Well-Known Document 0 / 5
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.
Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.
The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% 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/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/fatcat: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 11

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

Fatcat auth API

Helper methods and internal APIs for editor authentication. # TAGLINE

Fatcat changelog API

The **Changelog** is the ordered feed of editgroups which have been # TAGLINE accepted into the catalog. # TAGLINE

Fatcat containers API

**Container** entities represent publication venues like journals, # TAGLINE conference proceedings, book series, or blogs. They group publications # TAGLINE ("releases"). # TAG...

Fatcat creators API

**Creator** entities represent individuals (or organizations, or other # TAGLINE agents) who contribute to the creation of specific releases # TAGLINE (publications). # TAGLINE ...

Fatcat editgroups API

**Editgroups** are sets of changes, each to individual entities in the # TAGLINE catalog. Every edit must be part of an editgroup which is reviewed and # TAGLINE accepted (merge...

Fatcat editors API

**Editors** are human user accounts and bots that make changes to the # TAGLINE Fatcat catalog. # TAGLINE The API allows fetching (and updating) metadata about individual editor...

Fatcat files API

**File** entities represent unique digital files which are full # TAGLINE manifestations of specific releases (publications), such as fulltext PDF # TAGLINE files, JATS XML docu...

Fatcat filesets API

**Fileset** entities represent sets of digital files, as well as locations # TAGLINE where they can be found on the public web. Filesets most commonly # TAGLINE represent datase...

Fatcat releases API

**Release** entities represent specific published versions of a research # TAGLINE work, such as a pre-print, a journal article, a book (or chapter), or a # TAGLINE scholarly bl...

Fatcat webcaptures API

**Web Capture** entities represent archival snapshots of web pages (or # TAGLINE other web resources), which are usually complete manifestations of a # TAGLINE specific release ...

Fatcat works API

**Work** entities group several Release entities which are different # TAGLINE versions of the same abstract piece of research. For example, three # TAGLINE release entities rep...

Scroll for all 11

Open Collections 12

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

fatcat auth API

OPEN COLLECTION

fatcat auth changelog API

OPEN COLLECTION

fatcat auth containers API

OPEN COLLECTION

fatcat auth creators API

OPEN COLLECTION

fatcat auth editgroups API

OPEN COLLECTION

fatcat auth editors API

OPEN COLLECTION

fatcat auth files API

OPEN COLLECTION

fatcat auth filesets API

OPEN COLLECTION

fatcat auth releases API

OPEN COLLECTION

fatcat auth webcaptures API

OPEN COLLECTION

fatcat auth works API

OPEN COLLECTION

Scroll for all 12

Pricing Plans 1

Published pricing tiers and plan structures.

Plans

1 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Rate Limits

0 limits

RATE LIMITS

FinOps 1

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

Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

context Context

8 classes · 65 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Fatcat API Rules

6 rules · 5 warnings 1 info

SPECTRAL

JSON Schema 5

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

ContainerEntity

13 properties

JSON SCHEMA

CreatorEntity

10 properties

JSON SCHEMA

Editgroup

8 properties

JSON SCHEMA

FileEntity

13 properties

JSON SCHEMA

ReleaseEntity

26 properties

JSON SCHEMA

Examples 5

Example request and response payloads for these APIs.

Container Entity Example

12 fields

EXAMPLE

Creator Entity Example

9 fields

EXAMPLE

Editgroup Example

7 fields

EXAMPLE

File Entity Example

11 fields

EXAMPLE

Release Entity Example

21 fields

EXAMPLE

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Fatcat Authentication

apiKey · 1 scheme

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Fatcat Agentic Access

96 operations · 42 acting

96 operations · 42 acting

AGENTIC

Resources

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Access & Security 1

Authentication, authorization, and security posture

Authentication
Authentication

Operate 2

Status, limits, changes, and where to get help

IssueTracker
IssueTracker
 Releases
Releases

Other 1

Properties that don't map to a standard resource type

CapabilityMap
CapabilityMap

Source (apis.yml)

apis.yml Raw ↑ 
name: Fatcat
description: Fatcat is a versioned, user-editable open catalog of published research works maintained by the Internet Archive.
  It tracks bibliographic metadata, links papers to full-text copies, and preserves access to scholarly publications including
  journal articles, conference proceedings, and datasets across millions of research works.
deliveryModel:
  model: unknown
  open_source: unknown
  commercial: true
  callable_host: true
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - openapi
  - pricing
  - repository-unlicensed
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: free
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Free · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  generated: '2026-09-03'
  method: derived
image: https://fatcat.wiki/static/fatcat_logo.svg
url: https://fatcat.wiki/
tags:
- Scholarly
- Research
- Academic
- Open Access
- Bibliographic
- Publications
- Metadata
- Internet Archive
created: '2026-06-13'
modified: '2026-06-13'
specificationVersion: '0.23'
apis:
- aid: fatcat:fatcat-auth-api
  name: Fatcat auth API
  description: 'Helper methods and internal APIs for editor authentication.  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Authentication
  tags_raw:
  - auth
  properties:
  - type: OpenAPI
    url: openapi/fatcat-auth-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-changelog-api
  name: Fatcat changelog API
  description: 'The **Changelog** is the ordered feed of editgroups which have been  # TAGLINE

    accepted into the catalog.  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Changelog
  tags_raw:
  - changelog
  properties:
  - type: OpenAPI
    url: openapi/fatcat-changelog-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-containers-api
  name: Fatcat containers API
  description: '**Container** entities represent publication venues like journals,  # TAGLINE

    conference proceedings, book series, or blogs. They group publications  # TAGLINE

    ("releases").  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Container Entity Reference](https://guide.fatcat.wiki/entity_container.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Containers
  tags_raw:
  - containers
  properties:
  - type: OpenAPI
    url: openapi/fatcat-containers-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-creators-api
  name: Fatcat creators API
  description: '**Creator** entities represent individuals (or organizations, or other  # TAGLINE

    agents) who contribute to the creation of specific releases  # TAGLINE

    (publications).  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Creator Entity Reference](https://guide.fatcat.wiki/entity_creator.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Creators
  tags_raw:
  - creators
  properties:
  - type: OpenAPI
    url: openapi/fatcat-creators-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-editgroups-api
  name: Fatcat editgroups API
  description: '**Editgroups** are sets of changes, each to individual entities in the  # TAGLINE

    catalog. Every edit must be part of an editgroup which is reviewed and  # TAGLINE

    accepted (merged) as a whole.  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - editgroups
  properties:
  - type: OpenAPI
    url: openapi/fatcat-editgroups-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-editors-api
  name: Fatcat editors API
  description: '**Editors** are human user accounts and bots that make changes to the  # TAGLINE

    Fatcat catalog.  # TAGLINE


    The API allows fetching (and updating) metadata about individual editors,  # TAGLINE

    as well as fetching editor''s annotation and edit history.  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Editors
  tags_raw:
  - editors
  properties:
  - type: OpenAPI
    url: openapi/fatcat-editors-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-files-api
  name: Fatcat files API
  description: '**File** entities represent unique digital files which are full  # TAGLINE

    manifestations of specific releases (publications), such as fulltext PDF  # TAGLINE

    files, JATS XML documents, or video files. File entities also include a  # TAGLINE

    set of locations where they can be found on the public web.  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [File Entity Reference](https://guide.fatcat.wiki/entity_file.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - File
  tags_raw:
  - files
  properties:
  - type: OpenAPI
    url: openapi/fatcat-files-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-filesets-api
  name: Fatcat filesets API
  description: '**Fileset** entities represent sets of digital files, as well as locations  # TAGLINE

    where they can be found on the public web. Filesets most commonly  # TAGLINE

    represent datasets consisting of several data and metadata files.  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Fileset Entity Reference](https://guide.fatcat.wiki/entity_fileset.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - filesets
  properties:
  - type: OpenAPI
    url: openapi/fatcat-filesets-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-releases-api
  name: Fatcat releases API
  description: '**Release** entities represent specific published versions of a research  # TAGLINE

    work, such as a pre-print, a journal article, a book (or chapter), or a  # TAGLINE

    scholarly blog post. Releases are always grouped together under Works;  # TAGLINE

    they may be published in a specific Container; they may have known  # TAGLINE

    Creators; and there may exist known File/Fileset/WebCapture digital copies  # TAGLINE

    of the release.  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Release Entity Reference](https://guide.fatcat.wiki/entity_release.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Releases
  tags_raw:
  - releases
  properties:
  - type: OpenAPI
    url: openapi/fatcat-releases-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-webcaptures-api
  name: Fatcat webcaptures API
  description: '**Web Capture** entities represent archival snapshots of web pages (or  # TAGLINE

    other web resources), which are usually complete manifestations of a  # TAGLINE

    specific release entity. Web Captures also include a set of locations  # TAGLINE

    (wayback replay instances or WARC files) where the capture can be found.  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Web Capture Entity Reference](https://guide.fatcat.wiki/entity_webcapture.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - webcaptures
  properties:
  - type: OpenAPI
    url: openapi/fatcat-webcaptures-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
- aid: fatcat:fatcat-works-api
  name: Fatcat works API
  description: '**Work** entities group several Release entities which are different  # TAGLINE

    versions of the same abstract piece of research. For example, three  # TAGLINE

    release entities representing the pre-print, published article, and  # TAGLINE

    retraction stages of the same journal paper would be grouped under a  # TAGLINE

    single work.  # TAGLINE


    See the "Catalog Style Guide" section of the guide for details and  # TAGLINE

    semantics of what should be included in specific entity fields.  # TAGLINE

    Specifically, the  # TAGLINE

    [Work Entity Reference](https://guide.fatcat.wiki/entity_work.html).  # TAGLINE'
  humanURL: https://api.fatcat.wiki/redoc
  baseURL: https://api.fatcat.wiki/v0
  tags:
  - Works
  tags_raw:
  - works
  properties:
  - type: OpenAPI
    url: openapi/fatcat-works-api-openapi.yml
  - type: Documentation
    url: https://guide.fatcat.wiki/http_api.html
  - type: Redoc
    url: https://api.fatcat.wiki/redoc
  - type: GitHubRepository
    url: https://github.com/internetarchive/fatcat
  - type: PricingPage
    url: https://guide.fatcat.wiki/http_api.html
  - type: Plans
    url: plans/plans.yml
  - type: RateLimits
    url: rate-limits/rate-limits.yml
  - type: FinOps
    url: finops/finops.yml
maintainers:
- FN: Internet Archive
  url: https://archive.org/
  email: info@archive.org
common:
- type: CapabilityMap
  url: capabilities/fatcat-capability-edges.yml
  name: Fatcat Business Capability Map
- type: IssueTracker
  url: https://github.com/internetarchive/fatcat/issues
- type: Releases
  url: https://github.com/internetarchive/fatcat/releases
- type: AgenticAccess
  url: agentic-access/fatcat-agentic-access.yml
- type: Authentication
  url: authentication/fatcat-authentication.yml

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