scholarly-metadata
Crossref REST API
The authoritative registry of DOI metadata for scholarly publishing, covering roughly 165 million records. Look up any DOI to retrieve its bibliographic record, or search by title and author, on the website or through a free open API. It is the backbone reference for verifying citations and finding out what a DOI actually identifies.
Why it’s useful & how it works
Crossref is the authoritative source for DOI metadata because publishers register every DOI here when they assign it, making it the definitive place to confirm what a DOI actually identifies. You can look up any DOI directly on crossref.org or type a title and author into its search form to find the DOI for a work you already know. The API is free and requires no registration, though including your email address in requests places you in a faster, polite-use pool. Both directions work equally well: DOI to metadata, or title and author to DOI.
What’s inside
Nearly 180 million records as of the March 2026 public data file, covering journal articles, books, conference papers, datasets, and other scholarly outputs registered by more than 23,000 member publishers worldwide.
API access
https://api.crossref.org/works/ <doi> ; query ?query=...&mailto=<email>
What we measured
Our own probes, not the archive’s own claims. Re-run periodically; every reading below is dated.
Reachability
- Direct request
- Responded HTTP 200 387 ms
- Through a datacenter proxy
- Responded HTTP 200 556 ms
- API, direct
- Responded HTTP 200 528 ms
- API, through a proxy
- Responded HTTP 200 2.1 s
Did a real search return anything?
Returned results · 1427459 results for the sample query · median 7.9 s · stable across runs
Sample query: Climate Change and You
Benchmark coverage
Found 10 of 10 test items (100%) in the Academic papers cluster. Median response 183 ms.
By how well known the item is: 4/4 well-known, 4/4 mid, 2/2 obscure .
One item it found: Climate Change and You
Reachability measured 2026-08-22. Search checked 2026-08-22. Benchmark run 2026-08-22.
Access
Programmatic API access (a key may be required, see the API tag).