filter parameter with attribute-value pairs:
filter=attribute:value,attribute2:value2
Filters are case-insensitive.
Examples
curl "https://api.openalex.org/works?filter=type:book"
Logical expressions
Inequality
For numerical filters, use< and > for inequalities:
# Sources hosting more than 1000 works
https://api.openalex.org/sources?filter=works_count:>1000
from_publication_date and to_publication_date:
# Works published between Jan 1-26, 2022
https://api.openalex.org/works?filter=from_publication_date:2022-01-01,to_publication_date:2022-01-26
Negation (NOT)
Prepend! to negate any filter:
# All institutions except those in the US
https://api.openalex.org/institutions?filter=country_code:!us
Intersection (AND)
Comma-separated filters are combined with AND:# Works cited more than once AND open access
https://api.openalex.org/works?filter=cited_by_count:>1,is_oa:true
+:
# Works with authors from France AND UK
https://api.openalex.org/works?filter=institutions.country_code:fr,institutions.country_code:gb
The
+ syntax doesn’t work for search filters, boolean filters, or numeric filters.Addition (OR)
Use the pipe| to match any of multiple values:
# Works with authors from France OR UK
https://api.openalex.org/works?filter=institutions.country_code:fr|gb
# Get two works by DOI in one request
https://api.openalex.org/works?filter=doi:https://doi.org/10.1371/journal.pone.0266781|https://doi.org/10.1371/journal.pone.0267149
OR limit: You can combine up to 100 values with
| in a single filter. Use per_page=100 to get all results.OR works within a filter, not between filters. This will return an error:
# INVALID: OR between different filters
https://api.openalex.org/works?filter=institutions.country_code:fr|primary_location.source.issn:0957-1558
Available filters by entity
Each entity type has its own set of filterable fields. See the API reference for complete filter lists:| Entity | Filters |
|---|---|
| Works | publication_year, type, open_access.is_oa, author.id, institutions.id, cited_by_count, doi, has_abstract, and ~150 more |
| Authors | has_orcid, last_known_institutions.id, works_count, cited_by_count, orcid |
| Sources | is_oa, is_in_doaj, type, country_code, host_organization, issn |
| Institutions | country_code, type, is_global_south, continent, ror, has_ror |
| Topics | domain.id, field.id, subfield.id, works_count |
| Keywords | works_count, cited_by_count |
| Publishers | country_codes, hierarchy_level, ror, parent_publisher |
| Funders | country_code, is_global_south, continent, ror, awards_count |
Looking for text search? Filters match exact values. For full-text search in titles, abstracts, and other fields, see Searching.