GET /subfields
Operation ID: listSubfields
Auth: unknown
Description
Get a list of subfields (third-level topic categories). There are 254 subfields spread across 26 fields.
Parameters (10)
(string, query, required)
Your OpenAlex API key (required). Get a free key at https://openalex.org/settings/api
(string, query, optional)
Cursor for deep pagination. Use `cursor=*` to start, then use the `next_cursor` from the response.
(string, query, optional)
Filter subfields. Examples: `field.id:17`, `domain.id:3`, `works_count:>100000` See [all Subfield fields](/api-reference/subfields#available-filter-sort-and-group_by-fields).
(string, query, optional)
Group by: `field.id`, `domain.id` See [all Subfield fields](/api-reference/subfields#available-filter-sort-and-group_by-fields).
(integer, query, optional)
Page number for pagination. Use cursor for deep pagination beyond 10,000 results.
Constraints: {'minimum': 1}
(integer, query, optional, default: 25)
Number of results per page (1-100, default 25)
Constraints: {'minimum': 1, 'maximum': 100}
(integer, query, optional)
Return a random sample of N results (max 10,000). Cannot be used with sort or page.
Constraints: {'maximum': 10000}
(string, query, optional)
Full-text search across titles, abstracts, and other text fields. Example: `search=machine learning`
(string, query, optional)
Comma-separated list of fields to return. Reduces response size. Example: `select=id,display_name,cited_by_count`
(string, query, optional)
Sort by: `works_count`, `cited_by_count`. Prefix with `-` for descending. See [all Subfield fields](/api-reference/subfields#available-filter-sort-and-group_by-fields).
Examples (3)
| Title | Type | URL | Action |
|---|---|---|---|
| List subfields with pagination | curl |
https://api.openalex.org/subfields?per_page=50&page=1 |
|
| Filter subfields by field ID | curl |
https://api.openalex.org/subfields?filter=field.id:17 |
|
| Search subfields with sorting | curl |
https://api.openalex.org/subfields?search=machine%20learning&sort=works_count |
Probe History
Status Codes
| Time | Status | Latency | Size |
|---|---|---|---|
| 2026-03-23 10:44:22.426789 | 200 | 1277ms | |
| 2026-03-23 10:13:51.273115 | 200 | 807ms | |
| 2026-03-23 09:18:44.843731 | 200 | 442ms | 1.4MB |
Response Changes
| When | Old | New |
|---|---|---|
| 2026-03-23 10:13:51.273115 | 6f439f06dd62 |
d802854086dd |
| 2026-03-23 10:44:22.426789 | d802854086dd |
c1eeffbca5d4 |