OpenAlex API

OpenAlex is a comprehensive index of 250M+ scholarly works, authors, institutions, sources, and topics. It's the broadest multidisciplinary database in this skill.

Base URL

https://api.openalex.org

Authentication

• API key recommended (free). Get one at https://openalex.org/settings/api
• Pass as ?api_key=YOUR_KEY or Authorization: Bearer YOUR_KEY.
• Current access is budget-based; do not promise a higher quota from the legacy mailto parameter.

Rate Limits

• 100 requests/second max
• Usage-based pricing: $0.10/day without a key, $1/day with a free account key
• Single entity lookups by ID/DOI are free (unlimited)
• List + filter queries: ~$0.0001 each (~10,000/day free)
• Search queries: ~$0.001 each (~1,000/day free)

Key Endpoints

1. Get a single work

GET /works/{id}

Accepts multiple ID formats:

/works/W2741809807                              (OpenAlex ID)
/works/doi:10.7717/peerj.4375                  (DOI)
/works/pmid:29456894                            (PMID)
/works/https://doi.org/10.7717/peerj.4375      (full DOI URL)

2. Search works

GET /works?search={query}&per_page={n}&page={n}

Advanced search: Supports wildcards (machin*), fuzzy (machin~1), proximity ("climate change"~5), boolean grouping.

Example:

https://api.openalex.org/works?search=CRISPR+gene+therapy&filter=from_publication_date:2023-01-01&sort=cited_by_count:desc&per_page=10

3. Filter works

GET /works?filter={filters}

Key filter fields:

Operators: >, <, ! (negation), | (OR within filter)

Example:

https://api.openalex.org/works?filter=from_publication_date:2024-01-01,type:article,is_oa:true,cited_by_count:>50

4. Other entities

GET /authors?search={name}
GET /authors/{id}
GET /sources?search={name}          (journals, repositories)
GET /sources/{id}
GET /institutions?search={name}
GET /institutions/{id}
GET /topics/{id}

Authors and institutions accept similar filter/sort/pagination parameters.

5. Cursor pagination (for >10,000 results)

GET /works?filter=publication_year:2024&cursor=*&per_page=100

Response includes meta.next_cursor. Pass it as cursor={value} in the next request. Stop when next_cursor is null and the results are exhausted. The supported page maximum is 100; 200 is deprecated legacy behavior.

Response Format

Work object (key fields)

{
  "id": "https://openalex.org/W2741809807",
  "doi": "https://doi.org/10.7717/peerj.4375",
  "title": "The state of OA",
  "publication_year": 2018,
  "publication_date": "2018-02-13",
  "type": "article",
  "language": "en",
  "is_retracted": false,
  "cited_by_count": 1169,
  "open_access": {
    "is_oa": true,
    "oa_status": "gold",
    "oa_url": "https://doi.org/10.7717/peerj.4375"
  },
  "authorships": [{
    "author": {"id": "https://openalex.org/A5048491430", "display_name": "Heather Piwowar"},
    "institutions": [{"display_name": "Impactstory"}]
  }],
  "primary_location": {
    "source": {"display_name": "PeerJ", "issn_l": "2167-8359"}
  },
  "abstract_inverted_index": {"Despite": [0], "growing": [1], "interest": [2], ...},
  "referenced_works": ["https://openalex.org/W123...", ...],
  "ids": {"openalex": "...", "doi": "...", "pmid": "..."}
}

Abstract inverted index

Abstracts are stored as {word: [positions]}. Use the bundled parser:

python3 scripts/openalex_abstract.py work.json

It reports collisions and gaps instead of silently overwriting tokens. A null index means no abstract was supplied; select can also exclude the field.

List response

{
  "meta": {"count": 3771834, "page": 1, "per_page": 10},
  "results": [...]
}

Error Format

HTTP 403 for invalid API key, 429 for rate limit exceeded. Error responses include a message field.

Official sources reviewed 2026-09-30

• https://help.openalex.org/api/authentication/
• https://help.openalex.org/api/paging/
• https://help.openalex.org/api/searching/
• https://help.openalex.org/api/semantic-search/
• https://help.openalex.org/api/endpoints/
• https://help.openalex.org/access/example-costs/