Crossref REST
crossref.org · 2 records in Data APIs, Debrid · JSON
Records 2
- ★ qualifiesCrossref
Data APIsfree tieridentity anonymousno cardlimit request-rateevidence documentedstale on 2026-12-01
- ★ qualifiesCrossref REST API
Debridfree tieridentity anonymousno cardlimit request-rateevidence documentedstale on 2026-12-04duplicate
Crossref
Data APIs- Free allowance
- No sign-up: the public pool allows 5 requests a second for a single record and 1 a second for lists of records, 1 at a time; the polite pool, selected by an email address in the mailto parameter or the agent header, allows 10 a second for single DOI records and 3 a second for lists, 3 at a time...
- Verdict
- ★ qualifiesusable as stated; the read path was probed
- Cost
- free tier
- Identity
- anonymousno card, no phone
- Binding limit
- request-ratepublic pool: 5 requests a second for a single record, 1 a second for lists of records; concurrency 1; polite pool (email in mailto or the agent header): 10 requests a second for a single DOI record, 3 a second for lists; concurrency 3...
- Evidence
- documented31 sources; a first-party page was read and the sentence quoted
- Freshness
- stale on 2026-12-01checked 2026-10-31 (live); stale on 2026-12-01
| Free tier | No sign-up: the public pool allows 5 requests a second for a single record and 1 a second for lists of records, 1 at a time; the polite pool, selected by an email address in the mailto parameter or the agent header, allows 10 a second for single DOI records and 3 a second for lists, 3 at a time; no daily cap is published unit requests; metered on request-count; Measured on 2026-10-30: an anonymous list call answered x-rate-limit-limit 1, x-rate-limit-interval 1s, x-concurrency-limit 1 in pool public-array; an anonymous single-DOI call answered x-rate-limit-limit 5 in pool public-single. |
|---|---|
| Price | none stated |
| Limits |
|
| Binding | request-rate One list call a second anonymously, or 3 in the polite pool, makes a full harvest through the API slow; the annual file is the route to the whole registry. |
| Identity | anonymous No signup or registration. An email address in the mailto parameter or the agent header selects the polite pool with higher limits. Metadata Plus is an annual subscription that issues an API key. |
| Egress | The API is not metered by bytes. The annual public data file is distributed over Academic Torrents; its copy in the S3 bucket api-snapshots-reqpays-crossref is Requester Pays, so the downloader's AWS account pays the transfer, estimated by Crossref at USD 18 for the 2025 file of about 200 GB. free allowance: the torrent has no published cap; the Requester Pays copy has no free allowance |
| Per-object cap | rows default 20, maximum 1000 per call; cursor paging for deeper result sets |
| Retention | the API is a live index; the public data file is released once a year (the 2026 file on 2026 March 17); monthly snapshots for Metadata Plus subscribers stay available until the end of the following quarter |
| Interface | rest, s3 REST at https://api.crossref.org (works, members, funders, journals; JSON; cursor paging); the annual public data file as gzip JSONL over BitTorrent (Academic Torrents, doi:10.13003/nggf-vt1j) or from the Requester Pays S3 bucket api-snapshots-reqpays-crossref with --request-payer requester; monthly snapshots at https://api.crossref.org/snapshots/monthly/ for Metadata Plus tokens only endpoint: https://api.crossref.org/works |
| Tooling | curl or any HTTP client for the API; a BitTorrent client for the public data file; aws s3api get-object --request-payer requester for the S3 copy, which needs an AWS account |
| Composes with | The annual public data file is the bulk path: the 2026 file holds nearly 180 million records in 208 GB of compressed JSONL across 35909 files, free over Academic Torrents; the REST API with update-date or index-date filters, rows=1000 and a cursor brings a copy current between releases. |
| Reliability | Over the limit answers 429; a manual block answers 403 and is lifted through support. The public and polite limits were revised from 1 December 2025. |
| Notes | The record debrid/crossref-rest-api describes the same REST API; this record adds the published pool limits and the bulk paths. |
| Evidence note | documented The pool limits, the bulk file and its size are vendor pages read on 2026-10-30; two anonymous calls the same day returned the public-pool limits in their headers (1 a second for a list, 5 for a single DOI). The torrent was not downloaded. |
| Parsed numbers |
|
Evidence 31
| date | source | what it proved |
|---|---|---|
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the REST API needs no signup |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the polite pool is selected by an email address in mailto or the agent header |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the public pool allows 5 requests a second, concurrency 1 |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the polite pool allows 10 requests a second, concurrency 3 |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | Metadata Plus allows 150 requests a second with no concurrency limit |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | part of the text of Reliability, above |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | part of the text of Reliability, above |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the public pool allows 5 single-record requests a second |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the public pool allows 1 list request a second |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the polite pool allows 10 single-DOI requests a second |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the polite pool allows 3 list requests a second |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the limits are per second |
| 2026-10-30 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the limits were revised from 1 December 2025 |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ti | a call returns at most 1000 rows |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/rest-api/ti | deep result sets use cursor paging |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the public data file is released once a year |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the S3 copy is the bucket api-snapshots-reqpays-crossref |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the S3 copy is Requester Pays |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the S3 copy of the 2025 file costs about USD 18 |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | monthly snapshots are removed after the following quarter |
| 2026-10-30 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the public data file is distributed over Academic Torrents |
| 2026-10-30 | doi.org/10.13003/nggf-vt1j | the 2026 public data file is 35909 files |
| 2026-10-30 | doi.org/10.64000/7s70g-drz77 | the 2026 public data file is 208 GB compressed |
| 2026-10-30 | doi.org/10.64000/7s70g-drz77 | the 2026 public data file holds nearly 180 million records |
| 2026-10-30 | doi.org/10.64000/7s70g-drz77 | the 2026 public data file was announced on 2026 March 17 |
| 2026-10-30 | www.crossref.org/fees/ | the lowest Metadata Plus annual fee is USD 550 |
| 2026-10-30 | probe: https://api.crossref.org/works?rows=1&select=DOI | an anonymous list call was limited to 1 request |
| 2026-10-30 | probe: https://api.crossref.org/works?rows=1&select=DOI | the limit interval was 1 second |
| 2026-10-30 | probe: https://api.crossref.org/works?rows=1&select=DOI | the anonymous list call went to the public pool |
| 2026-10-30 | probe: https://api.crossref.org/works/10.1128/mbio.01735-25 | an anonymous single-DOI call was limited to 5 requests a second |
| 2026-10-30 | probe: https://api.crossref.org/works/10.1128/mbio.01735-25 | the anonymous single-DOI call went to the public pool |
More fields 3
| public file 2026 gb | 208 |
|---|---|
| public file 2026 files | 35909 |
| metadata plus min usd year | 550 |
Crossref REST API
Debrid- Free allowance
- No sign-up: the public pool allows 5 requests a second for a single record and 1 a second for lists of records, 1 at a time; the polite pool, selected by an email address in the mailto parameter or the agent header, allows 10 a second for a single DOI record and 3 a second for lists, 3 at a...
- Verdict
- ★ qualifiesusable as stated; the read path was probed
- Cost
- free tier
- Identity
- anonymousno card, no phone
- Binding limit
- request-ratepublic pool: 5 requests a second for a single record, 1 a second for lists of records, concurrency 1; polite pool (an email address in mailto or the agent header): 10 a second for a single DOI record, 3 a second for lists, concurrency 3
- Evidence
- documented29 sources; a first-party page was read and the sentence quoted
- Freshness
- stale on 2026-12-04checked 2026-11-03 (live); stale on 2026-12-04
| Free tier | No sign-up: the public pool allows 5 requests a second for a single record and 1 a second for lists of records, 1 at a time; the polite pool, selected by an email address in the mailto parameter or the agent header, allows 10 a second for a single DOI record and 3 a second for lists, 3 at a time; no daily cap is published unit requests; metered on request-count; The limits come back in the x-rate-limit-limit, x-rate-limit-interval and x-concurrency-limit response headers; an anonymous list call on 2026-10-31 answered x-rate-limit-limit 1, x-rate-limit-interval 1s and x-concurrency-limit 1 in pool public-array. |
|---|---|
| Price | USD 0 |
| Limits |
Monthly snapshots are a Metadata Plus benefit fetched with a Crossref-Plus-API-Token header; the free bulk path is the annual public data file over Academic Torrents. Without a token, a HEAD of the documented URL https://api.crossref.org/snapshots/monthly/latest/all.json.tar.gz answered 200 with a zero-byte text/html body on 2026-10-31. |
| Binding | request-rate One list call a second in the public pool, or 3 in the polite pool, each of at most 1000 rows, decides how many records a day the API yields; the annual public data file is the route to the whole registry. |
| Identity | anonymous No signup or registration. An email address in the mailto parameter or the agent header selects the polite pool with higher limits; it is not a credential. Metadata Plus is an annual subscription that issues an API key. |
| Egress | Free and unmetered. No key, no account, no allowance published. free allowance: no byte allowance published |
| Per-object cap | rows maximum 1000 per call; rows=1000 with a five-field select returned 773,304 bytes in one response on 2026-10-31 |
| Retention | A registered DOI cannot be fully deleted and its metadata can be updated, so a record is corrected rather than removed. |
| Interface | rest, cli GET https://api.crossref.org/works with rows, cursor and select; content negotiation for single records. The polite pool is signalled with mailto= or a User-Agent carrying an address. endpoint: https://api.crossref.org/works |
| Tooling | curl/python-requests; the harvester package and the documented cursor pattern. No SDK required. |
| Composes with | Crossref supplies the DOI-level citation graph and licence metadata; the full text behind each DOI is a separate fetch from the publisher or from an OA mirror such as PMC or Europe PMC. |
| Reliability | Over the rate limit answers 429; a manual block answers 403 and is lifted through support. Without a Metadata Plus token the monthly snapshot URLs answer 200 with an empty or stub HTML body instead of an error, so a client must check the bytes it saves. |
| Notes | Metadata only: bibliographic records with funding data, licence information, ORCID and ROR IDs and some abstracts, no full text. The record data-apis/crossref is the home of this offer and adds the annual public data file. |
| Evidence note | documented The pool limits are vendor pages read on 2026-10-31; an anonymous list call and an anonymous single-DOI call the same day returned the public-pool limits in their headers, and a rows=1000 call returned 773,304 bytes. The published limits were not tested at their ceiling. |
| Parsed numbers |
|
Evidence 29
| date | source | what it proved |
|---|---|---|
| 2026-10-23 | www.crossref.org/documentation/retrieve-metadata/rest-api/ | 'No sign-up is required to use the REST API' and the polite-pool mailto pattern |
| 2026-10-23 | www.crossref.org/documentation/retrieve-metadata/rest-api/ti | 'back off if you start seeing 429 statuses' - the only published rate signal; cursor paging for bulk |
| 2026-10-23 | probe: https://api.crossref.org/works?rows=1000&cursor=*&select=DOI,title,container-title,published,author | 200, 773,304 bytes of application/json in 3,456 ms - the real bytes per call |
| 2026-10-23 | probe: https://api.crossref.org/snapshots/monthly/latest.json.gz | 200 with 41 bytes of text/html and no file - the documented snapshot URL did not serve a snapshot |
| 2026-10-31 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the public pool allows 1 list request a second, concurrency 1; the page also gives 5 for a single record and 10 and 3 in the polite pool |
| 2026-10-31 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the free tier is a request rate |
| 2026-10-31 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the limits count requests |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the access page holds the pool limit table |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the polite pool allows 10 requests a second, concurrency 3 |
| 2026-10-31 | probe: https://api.crossref.org/works?rows=1&select=DOI | an anonymous list call went to the public list pool with a limit of 1 a second |
| 2026-10-31 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the public pool allows 5 single-record requests a second, concurrency 1 |
| 2026-10-31 | probe: https://api.crossref.org/works?rows=1000&cursor=*&select=DOI,title,container-title,published,author | a rows=1000 call with a five-field select returned 773,304 bytes |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ti | a call returns at most 1000 rows |
| 2026-10-31 | probe: https://api.crossref.org/snapshots/monthly/latest/all.json.tar.gz | the Metadata Plus snapshot URL answered HEAD 200 with a zero-byte text/html body and no token |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/bulk-downlo | the monthly snapshot route needs a Metadata Plus token |
| 2026-10-31 | probe: https://api.crossref.org/snapshots/monthly/latest.json.gz | the undocumented URL /snapshots/monthly/latest.json.gz answers an empty 41-byte HTML listing |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | a manual block answers 403 and support lifts it; the page also says over the limit answers 429 |
| 2026-10-31 | www.crossref.org/blog/announcing-changes-to-rest-api-rate-li | the polite pool allows 3 list requests a second; the public pool 1 |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the polite pool is selected by an email address in mailto or the agent header |
| 2026-10-31 | probe: https://api.crossref.org/works?rows=1000&cursor=*&select=DOI,title,container-title,published,author | the rows=1000 call answered with the public list limit of 1 a second |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ | the API carries bibliographic metadata with funding, licence, identifiers and abstracts |
| 2026-10-31 | probe: https://api.crossref.org/works/10.1128/mbio.01735-25 | an anonymous single-DOI call on 2026-10-31 went to the public single-record pool |
| 2026-10-31 | www.crossref.org/documentation/retrieve-metadata/rest-api/ac | the public pool allows 5 requests a second, concurrency 1 |
| 2026-11-02 | www.crossref.org/documentation/register-maintain-records/cre | Crossref states that a registered DOI cannot be fully deleted |
| 2026-11-02 | www.crossref.org/documentation/register-maintain-records/cre | the metadata of a DOI can be updated while the DOI string stays |
| 2026-11-02 | www.crossref.org/documentation/register-maintain-records/mai | DOIs cannot be deleted and their metadata can be updated |
| 2026-11-02 | www.crossref.org/members-area/canceling/ | registered DOIs and their metadata persist after a membership is cancelled |
| 2026-11-02 | www.crossref.org/members-area/canceling/ | a member that cancels can no longer update its metadata |
| 2026-11-02 | community.crossref.org/t/is-it-possible-to-remove-records-en | Crossref staff state that a DOI record cannot be removed and its metadata can be updated |
More fields 2
| rows 1000 bytes | 773304 |
|---|---|
| snapshot status | 200 with 41-byte HTML stub |