API Overview

OpenAlex REST API fundamentals

The OpenAlex API provides access to a comprehensive catalog of scholarly works, authors, sources, institutions, topics, and more.

New to OpenAlex? Start with the Guides for tutorials and walkthroughs. This API Reference is for detailed endpoint documentation.

Base URL

https://api.openalex.org

Authentication

Add your API key as a query parameter:

curl "https://api.openalex.org/works?api_key=YOUR_KEY"

API keys are free. Get yours here. See Authentication & Pricing for details.

Entities

The API is organized around these entity types:

Entity	Endpoint	Description
Works	/works	Scholarly documents (articles, books, datasets)
Authors	/authors	Researchers with disambiguated identities
Sources	/sources	Journals, repositories, conferences
Institutions	/institutions	Universities, research organizations
Topics	/topics	Research area classifications
Keywords	/keywords	Short phrases from works
Publishers	/publishers	Publishing organizations
Funders	/funders	Funding agencies
Awards	/awards	Research grants
Domains	/domains	Top-level topic hierarchy
Fields	/fields	Second-level topic hierarchy
Subfields	/subfields	Third-level topic hierarchy
SDGs	/sdgs	UN Sustainable Development Goals
Countries	/countries	Geographic entities
Continents	/continents	Geographic entities
Languages	/languages	Language classifications
Work Types	/work-types	Enumeration of work types
Source Types	/source-types	Enumeration of source types
Institution Types	/institution-types	Enumeration of institution types
Licenses	/licenses	Enumeration of licenses
Concepts	/concepts	Legacy taxonomy (deprecated)

Operations

Each entity supports these operations:

Operation	Pattern	Example
List	GET /{entities}	GET /works
Get	GET /{entities}/{id}	GET /works/W2741809807
Filter	GET /{entities}?filter=	GET /works?filter=publication_year:2024
Search	GET /{entities}?search=	GET /works?search=machine+learning
Aggregate	GET /{entities}?group_by=	GET /works?group_by=type

Response Format

All list endpoints return the same structure:

{
  "meta": {
    "count": 286750097,
    "db_response_time_ms": 152,
    "page": 1,
    "per_page": 25
  },
  "results": [
    { "id": "https://openalex.org/W2741809807", "title": "...", ... },
    { "id": "https://openalex.org/W2741809808", "title": "...", ... }
  ],
  "group_by": []
}

Field	Description
meta.count	Total results matching your query
meta.page	Current page number
meta.per_page	Results per page (default 25, max 100)
results	Array of entity objects
group_by	Aggregation results (when using group_by)

Quick Example

Get open access articles from 2024 with more than 100 citations:

curl "https://api.openalex.org/works?filter=publication_year:2024,is_oa:true,cited_by_count:>100&per_page=10&api_key=YOUR_KEY"

Query Parameters

Parameter	Description
api_key	Your API key (required)
filter	Filter by field values
search	Full-text search
sort	Sort results
per_page	Results per page (1-100)
page	Page number
cursor	Deep pagination cursor
sample	Random sample size
select	Limit returned fields
group_by	Aggregate by field

External IDs

Look up entities by external identifiers:

# By DOI
GET /works/https://doi.org/10.7717/peerj.4375
GET /works/doi:10.7717/peerj.4375

# By ORCID
GET /authors/https://orcid.org/0000-0001-6187-6610

# By ROR
GET /institutions/https://ror.org/0161xgx34

# By PMID
GET /works/pmid:29456894

OpenAPI Specification

The complete API specification is available for tooling and code generation:

OpenAPI Spec

Download the OpenAPI 3.1 specification

Next Steps

Authentication

API keys, pricing, and rate limits

Error Handling

Status codes and retry strategies

Key Concepts

IDs, dehydrated objects, and data model

LLM Reference

Optimized reference for AI agents