established · -0.2

Persistent Identifiers

Score 26.6 / 100 8 providers +70 via APIs 153 APIs Search apis.io →

Providers using this tag (8)

Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.

Developing 2 Usable, with meaningful gaps to close
Thin 3 Limited public surface area
Emerging 3 Early or largely undocumented

APIs with this tag (153)

Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →

Exemplar 2 Complete, well-documented, and agent-ready
Strong 2 Solid coverage with minor gaps
Developing 45 Usable, with meaningful gaps to close
Stanford Libraries PURL APIPersistent URLs into the Stanford Digital Repository. GET /{druid} returns HTML, /{druid}.xml returns the c...54.1Crossref membership — University of MinnesotaThe University of Minnesota is Crossref member 10551, registering DOIs under prefixes 10.24926 and 10.64517...53.4DataCite membership — University of MinnesotaThe University of Minnesota is a DataCite direct member, symbol UMN, registered since 2018-12-19 and linked...53.4ROR registration — University of MinnesotaThe University of Minnesota's Research Organization Registry identifier is https://ror.org/017zqws13. It is...53.4Crossref Membership (member 4211)The University of Warsaw is Crossref member 4211, holding 31 DOI prefixes used across its journals and pres...52.9DataCite DOI Registration (REPOD / REPOD.DBUW)The University of Warsaw registers DOIs through DataCite. Its DataCite provider is `repod` — "University of...52.9ROR Registration (039bjqg32)The Research Organization Registry record for the University of Warsaw, https://ror.org/039bjqg32, resolvab...52.9Crossref MembershipUnicamp is Crossref member 27633, "Universidade Estadual de Campinas", registering DOIs for its SBU journal...49.1DataCite Membership and DOI RegistrationUnicamp is a DataCite provider (member) in its own right, not merely a client of one. Verified 2026-09-01: ...49.1Crossref memberships (organic units)Five ULisboa organic units hold Crossref member IDs in their own right, minting DOIs for their journals ind...48.6DataCite repository membership (QWBT.ULISBOA)An active DataCite repository client registered to the university's central services for minting DOIs over ...48.6ROR organization identifierThe institution's registered ROR identifier — the canonical machine-readable organizational identity used a...48.6McMaster University DataCite RegistrationMcMaster University's membership of DataCite as a consortium organisation within the Canadian DataCite cons...48.2McMaster University Library Crossref MembershipMcMaster University Library's Crossref membership, under which it mints DOIs on its own prefix 10.15173 for...48.2McMaster University ROR RegistrationMcMaster University's entry in the Research Organization Registry, the persistent identifier that links the...48.2DataCite membership — Fondren Library, Rice UniversityRice University is a DataCite direct member, registered 2017-11-13 as provider `rice` (symbol RICE) under F...46.9ROR registration — Rice UniversityRice University's entry in the Research Organization Registry, ROR ID https://ror.org/008zs3103. It is the ...46.9Crossref membership (member 9411, prefix 10.22146)Universitas Gadjah Mada is a Crossref member in its own name — member id 9411, DOI prefix 10.22146 — verifi...46.6ROR organization record (ror.org/03ke6d638)Universitas Gadjah Mada's Research Organization Registry identifier, https://ror.org/03ke6d638, verified li...46.6OCHRE Data Service APIOCHRE (Online Cultural and Historical Research Environment) is the University of Chicago's item-level resea...46.1Digital Library Collections and the 10.7916 DOI namespaceColumbia University Libraries' digital collections platform and the resolution target for Columbia's own DO...44.7DataCite membership and repository registrationThe University of Freiburg is a DataCite member (symbol QVVC, country DE, consortium organization under the...44.0ROR organization identifierThe institution's Research Organization Registry identifier, https://ror.org/0245cg223, carrying its names ...44.0SADVR REST API (Vitrine-Recherche)Université de Montréal's own read-only research API, and the one genuinely institution-engineered contract ...43.9Crossref Membership — Charles UniversityCharles University holds two Crossref memberships: 5727, "Charles University in Prague, Karolinum Press" (t...43.1DataCite Membership — Washington University in St. Louis LibrariesWashington University in St. Louis Libraries is a DataCite direct member, symbol WUSTL, registered 2018-08-...43.1DataCite Registrant — Charles University (CUNI)Charles University is a DataCite registrant under provider symbol CUNI, memberType consortium_organization,...43.1ROR Registration — Charles UniversityCharles University is registered in the Research Organization Registry as https://ror.org/024d6js02, locate...43.1ROR Registration — Washington University in St. LouisThe institution's Research Organization Registry record, https://ror.org/01yc7t268, carrying its display na...43.1Crossref Membership — KIT LibraryThe KIT Library is a Crossref member in its own right, depositing DOIs under the prefix 10.58895. Verified ...43.0DataCite Membership — Karlsruhe Institute of Technology (KIT)KIT is a DataCite direct member, registering DOIs for its own research output rather than through a consort...43.0ROR Registry Record — Karlsruhe Institute of TechnologyKIT's Research Organization Registry identifier, https://ror.org/04t3en479, verified live 2026-09-01 agains...43.0DataCite Membership — University of Bonn (BXBQ)The University of Bonn is a DataCite member organization and mints DOIs for its research data. Verified 202...42.7ROR Registry Record — University of BonnThe University of Bonn's Research Organization Registry identifier, https://ror.org/041nas322, verified liv...42.7DataCite Membership — NYCU Research Data ServiceNYCU is a DataCite direct member in its own name — provider gtfe — and operates the DataCite repository cli...42.4ROR RegistrationNYCU's entry in the Research Organization Registry, ROR ID 00se2k293 — the canonical machine-readable ident...42.4DataCite Membership and DOI RegistrationChalmers is a DataCite consortium organization (member id ojuo, joined 2020-09-14, ROR https://ror.org/040w...41.5ORCID in Chalmers ResearchThe Chalmers Research CRIS surfaces ORCID iDs on researcher profiles and links out to the ORCID registry, e...41.5ROR RegistrationChalmers University of Technology is registered in the Research Organization Registry as https://ror.org/04...41.5Tsinghua University DataCite DOI Registration and ResolutionTsinghua University holds a DataCite membership in its own name — symbol TSINGHUA, memberType direct_member...40.3Crossref Membership — Massey UniversityMassey University registers DOIs with Crossref under member id 12895, prefixes 10.33217 and 10.54322, 314 D...39.6DataCite Membership — Massey UniversityMassey University is a DataCite member organization within the DataCite New Zealand consortium and mints DO...39.6ROR Registration — Massey UniversityMassey University's entry in the Research Organization Registry. This is the canonical machine-readable ide...39.6DataCite membership and DOI registration (member AWZY)The university is a DataCite member and DOI registrant — a fact about the institution, recorded here as a m...39.3ROR registration (Research Organization Registry)The institution's entry in the Research Organization Registry, ROR ID https://ror.org/03a1kwz48. A registry...39.3
Thin 89 Limited public surface area
Crossref DOI Registration (UKM Press and UKM faculties)Three Crossref memberships are held by units of Universiti Kebangsaan Malaysia, together accounting for 16,...39.2ROR Organization RegistrationUniversiti Kebangsaan Malaysia is registered in the Research Organization Registry as https://ror.org/00bw8...39.2Crossref membership via Liverpool University Press (member 2165)Liverpool University Press, the University's own publishing house, is Crossref member 2165. Verified 2026-0...38.8DataCite repository membership (BL.LPOOL)The University of Liverpool is a DataCite repository member and has been since 2015. Verified 2026-09-01: h...38.8ORCID affiliation programme (UK ORCID consortium)The University of Liverpool Library operates an ORCID member integration through the Jisc-run UK ORCID cons...38.8ROR organisation record (04xs57h96)The institution's entry in the Research Organization Registry. Verified 2026-09-01: https://api.ror.org/v2/...38.8Crossref Member 11812 - Universidad de los AndesDOI registration membership at Crossref. Member 11812, primary-name "Universidad de los Andes", location "B...38.7DataCite Consortium Organization UDLAC - Universidad de los Andes ColombiaDOI registration membership at DataCite. Consortium organization UDLAC, displayName "Universidad de los And...38.7ROR 02mhbdp94 - Universidad de los AndesResearch Organization Registry record for the institution. ROR ID 02mhbdp94, established 1948, declared dom...38.7DataCite Membership and DOI PrefixesThe University of Reading is a DataCite member — a fact about the institution, not a contract it operates. ...38.1ROR Organization RegistrationTongji University is registered in the Research Organization Registry with ROR ID https://ror.org/03rc6as71...38.1ROR Organization RegistrationThe university's entry in the Research Organization Registry, https://ror.org/05v62cm79 — machine-readable ...38.1SKKU Crossref Membership (DOI registration)Two Sungkyunkwan University units are Crossref members in their own right and register DOIs under their own...36.8SKKU ROR Registration (organization identifier)Sungkyunkwan University is registered in the Research Organization Registry as https://ror.org/04q78tk20, w...36.8Crossref MembershipThe University of Geneva is a Crossref member, id 13327, primary-name "Universite de Geneve". Recorded as a...36.6DataCite Repository MembershipUNIGE is a registered DataCite repository operator through the Swiss consortium (DataCite provider "opkb")....36.6Crossref DOI Registration MembershipTwo Kyushu University units are Crossref members registering DOIs under their own prefixes, verified agains...36.4DataCite DOI Registration MembershipKyushu University is a DataCite consortium organization — provider id `kyushuu`, symbol KYUSHUU, region APA...36.4ROR Organization RecordKyushu University's Research Organization Registry record, ROR ID 00p4k0j84, carrying the English, romanize...36.4Curtin University DOI Registration (DataCite)Curtin University is a DataCite member organisation and had minted 3,243 DOIs under its provider at time of...35.5Crossref membershipQUT is a Crossref member, id 3230, primary-name "Queensland University of Technology", verified live agains...35.3DataCite DOI and RAiD registrationQUT registers persistent identifiers with DataCite through the ARDC consortium. Two clients are evidenced: ...35.3ROR registrationQUT's Research Organization Registry identifier is https://ror.org/03pnv4752. The canonical machine-readabl...35.3LSE DOI Registration (DataCite)LSE is a registered DataCite provider — member identifier lcqr, "London School of Economics", memberType co...35.1Crossref Member 25426 (prefix 10.15460)The Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky — the university library and publisher of...34.8DataCite Registrant (prefix 10.25592)Universität Hamburg is a DataCite registrant. DOI prefix 10.25592 resolves to DataCite client tib.fdmuh, na...34.8ROR Registration (00g30e956)Universität Hamburg is registered in the Research Organization Registry as https://ror.org/00g30e956. Membe...34.8Crossref DOI Registration MembershipThree Tohoku University units are Crossref members registering DOIs under their own prefixes, verified agai...34.0ROR Organization RecordTohoku University's Research Organization Registry record, ROR ID 01dq60k83, carrying the English, romanize...34.0DataCite Consortium Membership (VIOJ)Leiden University is a DataCite consortium_organization with symbol VIOJ, organizationType academicInstitut...33.9ROR RegistrationLeiden University is registered in the Research Organization Registry as https://ror.org/027bh9e22, domain ...33.9DataCite membership (provider HLQC)TU Darmstadt registers DOIs through DataCite. Verified live 2026-09-01 via api.datacite.org/providers/hlqc:...32.9ROR registrationTU Darmstadt is registered in the Research Organization Registry as https://ror.org/05n911h24, established ...32.9Crossref membership (member 13551, prefix 10.53131)Sapienza is a Crossref member and DOI depositor. Verified live 2026-09-01 — https://api.crossref.org/member...32.5DataCite DOI registration (provider ROMAUNO / repository CRUI.UNIROMA1)Sapienza is a registered DataCite member and DOI registrant — a fact about the institution, not a contract ...32.5DataCite Membership and Open Research Exeter DOI RegistrationExeter is a registered DataCite member - provider symbol VUEX, name "University of Exeter", memberType cons...32.5ROR organization identifier 02be6w209Sapienza is registered in the Research Organization Registry with ROR ID https://ror.org/02be6w209, names "...32.5University of Exeter Press Crossref MembershipThe university's publishing arm is a Crossref member - member id 27616, primary name "University of Exeter ...32.5University of Exeter ROR RegistrationExeter is registered in the Research Organization Registry with ROR identifier https://ror.org/03yghzc09, t...32.5Crossref Open Funder Registry membershipWaseda University holds Crossref Open Funder Registry ID 501100004423, located in Japan, with 1,458 works a...32.4ROR registration (Research Organization Registry)Waseda University is registered in the Research Organization Registry as https://ror.org/00ntfnx83 — establ...32.4Crossref Membership (eleven faculty and institute member records)Chulalongkorn registers Crossref DOIs through eleven separate member records, one per faculty, institute or...32.1Crossref membership (member 49418)Crossref member 49418, "Trinity College Dublin, the University of Dublin", holding prefix 10.69731. As of t...32.1DataCite consortium membership (provider TCD)Trinity is a DataCite consortium organization, symbol TCD, country IE, linked to https://ror.org/02tyrky19....32.1DataCite Membership (consortium organization lygd)Chulalongkorn University is a DataCite consortium organization, provider id lygd, country TH, with one regi...32.1ROR organization record (02tyrky19)Trinity's Research Organization Registry identifier, https://ror.org/02tyrky19, the canonical machine-reada...32.1ROR Registration (https://ror.org/028wp3y58)Chulalongkorn University's Research Organization Registry record, carrying the Thai and English names, the ...32.1Crossref membership (member 37851)ASU is a Crossref member, id 37851, primary-name "Arizona State University", located in Tempe, AZ, depositi...31.8DataCite membership and repository registrationASU is a DataCite member (provider symbol ASU, memberType consortium_organization, created 2020-09-22) and ...31.8ROR organization record (03efmqc40)ASU's Research Organization Registry record, ror.org/03efmqc40, established 1885, status active, domain asu...31.8Crossref Membership (member 6332)The University of St Andrews Library is Crossref member 6332, holding 688 DOIs (151 current, 537 backfile) ...31.5DataCite Membership (provider NAHY)The University of St Andrews is a registered DataCite provider - id nahy, symbol NAHY, memberType consortiu...31.5ROR Registration (02wn5qz54)The University of St Andrews is registered in the Research Organization Registry as https://ror.org/02wn5qz...31.5Crossref Membership — member 25649Registered Crossref member 25649, "Instituto Tecnologico y de Estudios Superiores de Monterrey", Monterrey,...31.4DataCite Membership — ITESMTecnológico de Monterrey is a DataCite consortium organization, symbol ITESM, active, region AMER, country ...31.4ROR Registration — 03ayjn504Research Organization Registry identifier https://ror.org/03ayjn504, established 1943, domain tec.mx, locat...31.4Crossref membership (University of Wollongong Library, member 5587)The University of Wollongong Library is Crossref member 5587, holding the DOI prefix 10.14453 with 1,611 re...30.9DataCite membership (repository uow.figshare)The University of Wollongong is a DataCite consortium organization, symbol UOW, provider id uow, created 20...30.9ROR registration (00jtmb277)The University of Wollongong is registered in the Research Organization Registry as https://ror.org/00jtmb2...30.9ROR organization identifierUNAL is registered in the Research Organization Registry as https://ror.org/059yx9a68 ("National University...30.6DataCite Membership — University of Bern (UNIBE)The University of Bern is a DataCite direct member, registering DOIs for its research outputs. Verified 202...30.5ROR Registry Record — University of BernThe University of Bern's Research Organization Registry identifier, https://ror.org/02k7v4d05, verified liv...30.5ROR RegistrationITB is registered in the Research Organization Registry as https://ror.org/00apj8t60 ("Bandung Institute of...30.3DataCite Membership (VLEF)Humboldt-Universität zu Berlin is a DataCite member — provider symbol VLEF, memberType consortium_organizat...29.4ROR organization record — Case Western Reserve University (051fd9666)CWRU's Research Organization Registry record, https://ror.org/051fd9666, established 1826, domain case.edu,...29.4Handle.Net naming authority 10576Qatar University holds Handle.Net prefix 10576 and every QSpace item carries a persistent identifier under ...29.3University of Alberta Library DOI Registration (DataCite)The University of Alberta Library is a registered DataCite repository — client id ualberta.library, symbol ...29.3University of Copenhagen DataCite Membership (XIZZ)The university is an active DataCite member — provider symbol XIZZ, memberType consortium_organization, isA...29.3Crossref Membership (member 14960, prefix 10.31009)UPF is a Crossref member and registers DOIs under its own prefix. Probed 2026-09-01: GET https://api.crossr...29.2Otago Scholarly Identifier Registrations (DataCite + Crossref)Otago's persistent-identifier registrations, readable through each registry's public REST API. Confirmed li...29.2ROR Registration (04n0g0b29)UPF's entry in the Research Organization Registry. Probed 2026-09-01: GET https://api.ror.org/v2/organizati...29.2Crossref Membership (member 7412)The Ohio State University Libraries is Crossref member 7412 with 4,927 registered DOIs, covering the journa...28.9DataCite Membership (GVUZ)The Ohio State University is a DataCite direct member, provider symbol GVUZ, active, linked to ROR https://...28.9ROR RegistrationThe Ohio State University is registered in the Research Organization Registry as https://ror.org/00rs6vg23,...28.9Crossref member and DOI prefixQueen Mary is a Crossref member, id 11031, holding DOI prefix 10.26494. Recorded as a registry membership o...28.8DataCite member organisation and repository clientQueen Mary is a DataCite member organisation, provider id "iuar", memberType consortium_organization, linke...28.8ROR organisation identifierQueen Mary's Research Organization Registry identifier, https://ror.org/026zzn846. It is the join key that ...28.8Crossref membership — Penerbit UTM Press (member 4787, prefix 10.11113)UTM's own university press is a Crossref member in its own right, not a customer of someone else's prefix: ...28.4ROR registration — https://ror.org/026w31v75UTM is registered in the Research Organization Registry as ror.org/026w31v75, with domain utm.my, establish...28.4Handle System prefix 10938 (AUB ScholarWorks)AUB holds Handle System prefix 10938, the persistent identifier namespace behind every AUB ScholarWorks rec...28.0ROR registry entry (Research Organization Registry)Wuhan University is registered in ROR as https://ror.org/033vjfk17 (active, established 1893), cross-walked...27.5Crossref membership and DOI prefixesThe University of Aberdeen is Crossref member 12669, located "Aberdeen, United Kingdom", holding DOI prefix...27.3DataCite membership and registered repositoryThe University of Aberdeen is a DataCite member — provider symbol HUGZ, memberType consortium_organization,...27.3ROR organization registrationThe University of Aberdeen is registered in the Research Organization Registry as https://ror.org/016476m91...27.3Crossref membership (member 32492, prefix 10.60923)The University of Bologna is a Crossref member and DOI depositor. Verified live 2026-09-01 — https://api.cr...27.0DataCite DOI registration (provider UYEY, 32,291 DOIs)The University of Bologna is a registered DataCite member and DOI registrant — a fact about the institution...27.0ROR organization identifier 01111rn36The University of Bologna is registered in the Research Organization Registry with ROR ID https://ror.org/0...27.0Crossref membership — DOI prefix 10.47836Universiti Putra Malaysia is a Crossref member in its own right, member id 27687, holding DOI prefix 10.478...26.9ROR organization recordUniversiti Putra Malaysia holds ROR identifier https://ror.org/02e91jd64, cross-walked in the ROR record to...26.9
Emerging 15 Early or largely undocumented
DataCite DOI Registrant — Griffith UniversityGriffith University is a DataCite provider, registering DOIs for its research outputs and datasets. Provide...26.1Crossref Membership — Servicio de Publicaciones de la UAMUAM's publications service is a Crossref member (member id 6788) and mints DOIs under prefix 10.15366, with...25.9ROR Registration — Universidad Autónoma de MadridUAM's Research Organization Registry identifier, https://ror.org/01cby8j38, the canonical machine-readable ...25.9USC DataCite DOI Registration (Provider Account)USC holds a DataCite direct membership in its own name and mints DOIs for eleven USC repositories under it....25.0Crossref Membership (DOI prefix 10.15581)The University of Navarra is a Crossref member and registers DOIs under its own prefix 10.15581 — 33,267 DO...24.9ROR RegistrationThe institution's entry in the Research Organization Registry, the open identifier used to disambiguate res...24.9Crossref membershipThe University of Chile is a Crossref member, id 3330, primary name "Universidad de Chile", DOI prefix 10.5...24.1DataCite membership and repository registrationThe University of Chile is a DataCite member, not a DataCite operator. Evidenced 2026-09-01 from the DataCi...24.1Crossref Membership (member 34483, prefix 10.55582)Tianjin University is a Crossref member in its own right — member id 34483, DOI prefix 10.55582 — and is al...23.4ROR Registration (https://ror.org/012tb2g32)Tianjin University's Research Organization Registry record — the canonical machine-readable identifier for ...23.4Handle System Prefix 2115Hokkaido University Library holds Handle System naming authority prefix 2115, which mints the persistent id...23.2JaLC DOI Prefix 10.14943Hokkaido University registers DOIs through JaLC, the Japan Link Center, under prefix 10.14943. Confirmed fr...23.2Queen's University Belfast Research Portal — DataCite repository clientQueen's University Belfast is a DataCite consortium organization (provider jxtg) and has operated a registe...22.0Deakin University Crossref membership (member 8935)Deakin is a Crossref member depositing its own DOIs under prefix 10.21153 — 1,303 works, predominantly jour...20.0Deakin University DataCite repository (ARDCX.DEAKIN)Deakin's own DataCite repository account, held under the ARDC (Australian Research Data Commons) consortium...20.0

Companies reaching this through an API (70)

These companies publish an API, specification or operation carrying “Persistent Identifiers” but do not classify their business under it. Listed unranked and kept out of the count above, because one tagged operation is not a statement about what a company does.

American University of Beirut Arizona State University Autonomous University of Madrid Bandung Institute of Technology Case Western Reserve University Chalmers University of Technology Charles University Chulalongkorn University Columbia University Curtin University Deakin University EU Open Data Portal Gadjah Mada University Griffith University Humboldt-Universität zu Berlin Karlsruhe Institute of Technology Kyushu University Leiden University London School of Economics and Political Science Massey University McMaster University National University of Colombia National Yang Ming Chiao Tung University Ohio State University Qatar University Queen Mary University of London Queen's University Belfast Queensland University of Technology Rice University Sapienza University of Rome Stanford University Sungkyunkwan University Technical University of Darmstadt Tecnológico de Monterrey Tohoku University Tongji University Trinity College Dublin Tsinghua University Universitat Pompeu Fabra Universiti Kebangsaan Malaysia Universiti Putra Malaysia Universiti Teknologi Malaysia University of Aberdeen University of Alberta University of Bern University of Bologna University of Bonn University of California, San Diego University of Campinas University of Chicago
Show all 70 companies ↓

Score breakdown

Frequency
58.2
log-scaled weighted occurrences
Breadth
0.2
spread across providers
Quality lift
35.9
mean composite of providers using it
Cohesion
31.9
strength of nearest seed neighbor

Related tags

DOI 69 co-occurrences ROR 56 co-occurrences Crossref 47 co-occurrences DataCite 51 co-occurrences Scholarly Publishing 38 co-occurrences Shibboleth 61 co-occurrences Identity Federation 70 co-occurrences Research Data 60 co-occurrences

Where this tag comes from

Api tag152
Provider tag8
Openapi tag1

Work with this as data

Every tag here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for tags

7 MCP tools reach this
  • find_tagsBrowse and filter every tag in the catalog.
  • get_cohortThis tag as a scored cohort — every provider carrying it, with scores.
  • cohort_statsPRO — the distribution across this tag: mean, median, band split, adoption rates.
  • cohort_rankingsPRO — the leaderboard, on composite AND agent-readiness axes.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This tag
curl "https://apis.io/api/v1/tags/persistent-identifiers"
All tags
curl "https://apis.io/api/v1/tags?limit=25"
As a scored cohort
curl "https://apis.io/api/v1/cohorts/tag/persistent-identifiers"
The distribution (Pro)
curl "https://apis.io/api/v1/cohorts/tag/persistent-identifiers/stats" \
  -H "X-API-Key: $APIS_IO_KEY"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

A second provider on the same verified email joins the account you already have.