Citations of online sources that require registration or a subscription are acceptable in Wikipedia as documented in Verifiability § Access to sources. As a courtesy to readers and other editors, editors should signal the access restrictions of the external links included in a citation. Nota bene: access icons do not display correctly for editors who use Modern skin.

Four access levels can be used:

  • Freely accessible free: the source is free to read for anyone (this applies in particular to articles in open access)
  • Free registration required registration: a free registration is required to access the source
  • Free access subject to limited trial, subscription normally required limited: there are other constraints (such as a cap on daily views) to freely access this source
  • Paid subscription required subscription: the source is only accessible via a paid subscription ("paywall")

As there are often multiple external links with different access levels in the same citation, these values are attributed to a particular external link.

Access indicators for url-holding parameters
ಸಂಪೊಲಿಪುಲೆ

Sources linked by |url=, |chapter-url=, |entry-url=, |article-url=, and |section-url= are presumed to be free-to-read. When they are not free-to-read, editors should mark those sources with the matching access-indicator parameter so that an appropriate icon is included in the rendered citation. Because the sources linked by these url-holding parameters are presumed to be free-to-read, they may not be marked as free.

url-holding and access-indicator parameters
url access allowed keywords
|url= |url-access= registration Free registration required
limited Free access subject to limited trial, subscription normally required
subscription Paid subscription required
|article-url= |article-url-access=
|chapter-url= |chapter-url-access=
|contribution-url= |chapter-url-access=dagger
|entry-url= |entry-url-access=
|section-url= |section-url-access=

dagger|contribution-url-access= not currently defined; use its alias |chapter-url-access=

Access indicators for named identifiers
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Links inserted by named identifiers are presumed to lie behind a paywall or registration barrier – exceptions listed below. When they are free-to-read, editors should mark those sources with the matching access-indicator parameter so that an appropriate icon is included in the rendered citation. Because the sources linked by these named-identifier parameters are not presumed to be free-to-read, they may not be marked as limited, registration, or subscription.

named-identifier and access-indicator parameters
identifier access allowed keywords
|bibcode= |bibcode-access= free Freely accessible
|doi= |doi-access=
|hdl= |hdl-access=dagger
|jstor= |jstor-access=
|ol= |ol-access=
|osti= |osti-access=

Some named-identifiers are always free-to-read. For those named-identifiers there are no access-indicator parameters, the access level is automatically indicated by the template. These named identifiers are:

  • |arxiv=
  • |biorxiv=
  • |citeseerx=
  • |pmc=
  • |rfc=
  • |ssrn=
Ambiguous access parameters
ಸಂಪೊಲಿಪುಲೆ

The parameters |registration=yes and |subscription=yes can also be used to indicate the access level of a citation. However, they do not indicate which link they apply to, so editors are encouraged to use |url-access=registration and |url-access=subscription instead, when the restriction applies to |url=. If the restriction applies to an identifier, these parameters should be omitted.

These parameters add a link note to the end of the citation:

  • registration: (deprecated) For online sources that require registration, set |registration=yes (or y, or true); yields to subscription if both are set. Use the appropriate access-indicator parameter
  • subscription: (deprecated) For online sources that require a subscription, set |subscription=yes (or y, or true); supersedes registration if both are set. Use the appropriate access-indicator parameter

Setting |registration= or |subscription= to any value other than y, yes, or true will generate an error message.