Ossus

Ossus builds AI-native intelligence for cultural institutions, starting with libraries. Its flagship product is Ossus ILS, a modern integrated library system that unifies cataloguing, circulation, acquisitions, analytics, and patron discovery in one interface, with an AI copilot that drafts MARC records, subjects, and classifications for librarian approval. A lighter product, Librar, targets school libraries with fast mobile setup. AI add-ons cover camera-based shelf inventory, vendor comparison for purchasing, and grant finding. Ossus emphasizes privacy-first design: it does not train on or sell customer data and works only with catalogue metadata rather than borrower records. Ossus is a Y Combinator (Winter 2026) company based in San Francisco.

Ossus is profiled on the APIs.io network. Tagged areas include Company, Libraries, Library Management, Integrated Library System, and Cataloguing.

Ossus’ developer surface includes engineering blog and 4 more developer resources.

🌐 Visit website 📡 Source on GitHub

7.6/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

0 APIs

Company LibrariesLibrary ManagementIntegrated Library SystemCataloguingMARCCultural InstitutionsArtificial Intelligence Education

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 7.6/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 0.4 / 17

Access Clarity 2.7 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.3 / 9

Regulatory Posture 3.1 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 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 could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/. 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/ossus: 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 →

Security Posture 2

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

Ossus Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Ossus Trust Center

SOC 2, ISO 27001

SECURITY

Resources

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Compliance

Compliance

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: ossus
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - none
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/ossus.png
name: Ossus
description: 'Ossus builds AI-native intelligence for cultural institutions, starting with libraries. Its flagship product
  is Ossus ILS, a modern integrated library system that unifies cataloguing, circulation, acquisitions, analytics, and patron
  discovery in one interface, with an AI copilot that drafts MARC records, subjects, and classifications for librarian approval.
  A lighter product, Librar, targets school libraries with fast mobile setup. AI add-ons cover camera-based shelf inventory,
  vendor comparison for purchasing, and grant finding. Ossus emphasizes privacy-first design: it does not train on or sell
  customer data and works only with catalogue metadata rather than borrower records. Ossus is a Y Combinator (Winter 2026)
  company based in San Francisco.'
url: https://raw.githubusercontent.com/api-evangelist/ossus/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
tags:
- Company
- Libraries
- Library Management
- Integrated Library System
- Cataloguing
- MARC
- Cultural Institutions
- Artificial Intelligence
- Education
apis: []
common:
- type: TrustCenter
  url: security/ossus-trust-center.yml
- type: DomainSecurity
  url: security/ossus-domain-security.yml
- type: Website
  url: https://www.ossus.com
- type: Blog
  url: https://www.ossus.com/blog
- type: Compliance
  url: https://trust.ossus.com/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 2
  pass: local-v1

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