DOAJ (Directory of Open Access Journals)

A curated directory of open-access journals and the articles those journals have registered with DOAJ. Use it to answer "is this journal in DOAJ?" or "articles in DOAJ-listed journals matching X." It is not a general literature index and it is not Unpaywall.

Nature is not in DOAJ. A paper can be open access (hybrid, bronze, green) without its journal being listed here. For "is there a free PDF of this DOI?" use Unpaywall. For the yes/no "is this journal in DOAJ?" when you are already on OpenAlex, GET /sources/issn:{issn} returns is_in_doaj (PLoS ONE 1932-6203 is true; Nature 0028-0836 is false) — stay there. Come to DOAJ when you need APC, licence, or oa_start. For "papers on CRISPR" use PubMed / OpenAlex, then optionally restrict to DOAJ journals.

All figures below verified 2026-09-10 against API v4.

Base URL

https://doaj.org/api

Docs (live): https://doaj.org/api/docs

Search URLs you write as /api/search/... are served as v4; next links in the JSON point at /api/v4/search/.... Either form works.

Authentication

Public search needs no key. API keys are for publisher submitters. Do not ask the user for a DOAJ key to look up a journal.

Rate Limits

No published per-second cap. Be polite. Prefer a journal ISSN lookup over paging through tens of thousands of article hits.

Query syntax

The path segment is the query (Elasticsearch query string). Slash in a DOI is escaped for you.

Goal	Query
Article title words	`bibjson.title:CRISPR`
DOI	`doi:10.3389/fpsyg.2013.00479`
Journal ISSN	`issn:1932-6203`
Exact journal title	`bibjson.title.exact:"PLoS ONE"`
Short names	`title:`, `issn:`, `publisher:`, `license:` (journals)

.exact works on full field names, not on the short aliases.

Key Endpoints

1. Search articles

GET /search/articles/{query}?page=1&pageSize=10

GET /search/articles/bibjson.title:CRISPR?pageSize=2

Verified: total 7777, page 1, pageSize 2, results length 2. next was https://doaj.org/api/v4/search/articles/bibjson.title:CRISPR?page=2&pageSize=2. Follow next (or increment page) rather than guessing a last page — last pointed at page 3889.

Each result has id, created_date, last_updated, bibjson. Identifiers are a list:

"identifier": [
  {"id": "10.3390/v14102045", "type": "doi"},
  {"id": "1999-4915", "type": "eissn"}
]

Pick type == "doi". Do not take identifier[0] blindly (it may be an ISSN).

2. Search journals

GET /search/journals/{query}?page=1&pageSize=10

Verified:

Query	`total`	Notes
`issn:0028-0836` (Nature)	0	Subscription journal. Empty is the answer.
`issn:1932-6203` (PLoS ONE)	1	`bibjson.title` `PLoS ONE`, `oa_start` 2006, `apc.has_apc` true, max 2477 USD

HTTP 200 + total: 0 + results: [] means "not a DOAJ journal," not an outage. Unpaywall may still find a green or hybrid copy of a Nature paper.

Journal bibjson includes title, ISSNs, publisher, license, APC, and oa_start. That is the record to quote when someone asks "is this journal OA in DOAJ?"

Typical Workflow

Have an ISSN or journal title → /search/journals/issn:{issn}.
Have a DOI you believe is in a DOAJ journal → /search/articles/doi:{doi}.
If journals search is empty, say so and check Unpaywall for the article.
Do not page bibjson.title:CRISPR as a substitute for PubMed.

Failure Modes

What you did	What happens	What to do
ISSN of a non-DOAJ journal	200, `total: 0`	Report "not in DOAJ"; try Unpaywall
Took `identifier[0]` as the DOI	You may get an eISSN	Filter `type == "doi"`
Used DOAJ as Unpaywall	Misses hybrid/green OA	Article-level OA is Unpaywall
Second host just for yes/no	Extra call	OpenAlex `sources.is_in_doaj` if you are already there
Used short field + `.exact`	Query does not mean what you think	Use `bibjson.title.exact`