OpenCitations
OpenCitations is an open science research infrastructure providing free access to scholarly bibliographic and citation data. It offers REST APIs for querying citation networks, DOI-based citation lookups, reference data, and bibliographic metadata from millions of research articles. All data is published under CC0 Public Domain Waiver for unrestricted reuse.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles OpenCitations the way a machine reads it — 15 machine-readable artifacts across 6 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — OpenCitations scores 29.8/100 (emerging), with a separate agent-readiness read of 41/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile OpenCitations
Each block below is one kind of artifact we hold for OpenCitations. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 6
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
OpenCitations SPARQL Endpoint
SPARQL endpoints for structured queries against the OpenCitations Meta and Index datasets. Provides access to the full Linked Open Data graph for both bibliographic metadata and...
OpenCitations Authors API
Operations for retrieving works by author
OpenCitations Citations API
Operations for retrieving citation metadata and counts
OpenCitations Editors API
Operations for retrieving works by editor
OpenCitations Metadata API
Operations for retrieving bibliographic metadata
OpenCitations References API
Operations for retrieving outgoing reference data
Semantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Opencitations Context
JSON-LDExamples 5
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Author Works
EXAMPLECitation By Oci
EXAMPLECitation Count
EXAMPLEIncoming Citations
EXAMPLEMetadata Lookup
EXAMPLESecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for OpenCitations — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Access & Security 2
Authentication, authorization, and security posture
← All providers · Data indexed from github.com/api-evangelist/opencitations · machine-readable index on apis.io