To prevent conflicts in new namespaces added by extensions, please list your extension's custom namespaces here on the list of extension default namespaces. If you define a constant for a custom namespace, list it here, too.

Note that these are only default namespaces. All extensions defining new namespaces should provide the installer with a method of configuring the extension to use a different range of namespaces for its custom namespaces.

In general, extensions should reserve namespace numbers in blocks of 10, where no known namespaces are already added by MediaWiki core or any known extensions (see discussion). Each block is intended for an extension to use sequentially; in particular, extensions that add more than one custom namespace should not reserve an additional block for each additional namespace unless the extension has exhausted its current block.

Namespace numbers between 3000 and 4999 should not be used; these numbers are reserved for wikis to define their custom namespaces. Furthermore, care should be taken when selecting numbers under 1000 since this range has historically been quite heavily used by extensions and sites alike (numbers under 200 should probably be avoided altogether).

Naturally, some namespaces listed on this page will overlap and violate the recommendations. The recommendations are good practices new extensions should adhere to avoid conflicts; for legacy reasons, old extensions that have already created conflicts and bad practices can't simply be changed but are listed here to help avoid even more conflicts.

This page in a nutshell: MediaWiki core uses namespace numbers under 100. These must never be used by extensions or sites. Avoid namespace numbers 100–199. These were historically used by both extensions and sites. Custom namespaces on sites should use namespace numbers 3,000–4,999. These should not be used by extensions. Extensions should use namespace numbers between 200 and 2,999, or between 5,000–9,999. Avoid namespace numbers above 10,000. These are reserved for future use.

Negative IDs

Warning:

Do not use negative IDs for extensions. Ever.

ID 0–99

ID 100–199

Warning:

The namespaces in the range 100–199 have historically been heavily used by both extensions and individual wikis for their custom namespaces. Because of this, it is generally recommended to avoid this range for new namespaces.

100–119

Semantic MediaWiki

Semantic MediaWiki

ID	Name	Constant	Remark
100	Relation:	SMW_NS_RELATION	Introduced in version 0.1, no longer used as of version 1.0, and removed in version 1.5.0.
101	Relation_talk:	SMW_NS_RELATION_TALK	Introduced in version 0.1, no longer used as of version 1.0, and removed in version 1.5.0.
102	Property:	SMW_NS_PROPERTY	Introduced in version 0.1.  Note: Namespace name also used by Wikibase
103	Property_talk:	SMW_NS_PROPERTY_TALK	Introduced in version 0.1.  Note: Namespace name also used by Wikibase
104	Type:	SMW_NS_TYPE	Introduced in version 0.1, no longer used as of version 1.6.0, and removed in version 3.0.0.
105	Type_talk:	SMW_NS_TYPE_TALK	Introduced in version 0.1, no longer used as of version 1.6.0, and removed in version 3.0.0.
108	Concept:	SMW_NS_CONCEPT	Introduced in version 1.2.0.
109	Concept_talk:	SMW_NS_CONCEPT_TALK	Introduced in version 1.2.0.
112	smw/schema:	SMW_NS_SCHEMA	Introduced in version 3.0.0.
113	smw/schema_talk:	SMW_NS_SCHEMA_TALK	Introduced in version 3.0.0.
114	Rule:	SMW_NS_RULE	Introduced in version 3.0.0, never used, and removed in version 5.0.0.
115	Rule_talk:	SMW_NS_RULE_TALK	Introduced in version 3.0.0, never used, and removed in version 5.0.0.

Page Forms

Page Forms

ID	Name	Constant	Remark
106	Form:	PF_NS_FORM	Before the extension was renamed, this namespace's constant name was SF_NS_FORM.
107	Form_talk:	PF_NS_FORM_TALK	Before the extension was renamed, this namespace's constant name was SF_NS_FORM_TALK.

DPLforum

DPLforum

ID	Name	Constant	Remark
110	Forum:	NS_FORUM	Before r93293, this namespace number was not hardcoded, and a number of wikis previously used other numbers, with 110 used for unrelated namespaces.
111	Forum_talk:	NS_FORUM_TALK	Before r93293, this namespace number was not hard coded, and several wikis previously used other numbers, with 111 used for unrelated namespaces.

120–129; 140–149: Wikibase

Wikibase Repository

ID	Name	Constant	Remark
120	Item:	WB_NS_ITEM	Can be customized via $wgWBClientSettings['entitySources']['poolwiki']['entityNamespaces']['item']. Many installations, including Wikidata, use the main namespace instead.
121	Item_talk:	WB_NS_ITEM_TALK	many installations, including Wikidata, use the main talk namespace instead
122	Property:	WB_NS_PROPERTY	Can be customized via $wgWBClientSettings['entitySources']['poolwiki']['entityNamespaces']['property']. Wikidata uses namespace ID 120 instead.  Note: Namespace name also used by Semantic MediaWiki
123	Property_talk:	WB_NS_PROPERTY_TALK	Wikidata uses namespace ID 121 instead.  Note: Namespace name also used by Semantic MediaWiki
124	Query:	WB_NS_QUERY	Can be customized via $wgWBClientSettings['entitySources']['poolwiki']['entityNamespaces']['query']. Wikidata uses namespace ID 122 instead.
125	Query_talk:	WB_NS_QUERY_TALK	Wikidata uses namespace ID 123 instead.

WikibaseLexeme

ID	Name	Constant	Remark
146	Lexeme:	WB_NS_LEXEME	Can be customized via $wgWBClientSettings['entitySources']['poolwiki']['entityNamespaces']['lexeme'].
147	Lexeme_talk:	WB_NS_LEXEME_TALK

ID 200–299

ID 300–399

ID 400–499

470–479: EventLogging

EventLogging

ID	Name	Constant	Remark
470	Schema:	NS_SCHEMA	JSON schemas describing data models  Note: Namespace name also used by LinkedWiki and (formerly) EntitySchema  Note: Constant name also used by LinkedWiki
471	Schema_talk:	NS_SCHEMA_TALK	Note: Namespace name also used by LinkedWiki and (formerly) EntitySchema  Note: Constant name also used by LinkedWiki

480–489

JsonConfig

JsonConfig

ID	Name	Constant	Remark
482	Config:	NS_CONFIG	JSON Configuration blob used by multiple systems
483	Config_talk:	NS_CONFIG_TALK
486	Data:	NS_DATA	Additional JSON data. As of 2015Category:Pages containing potentially dated statements you can store arbitrary valid JSON in the subnamespace Data:Json, e.g., Data:Json:MyDataset. This is a developing convention on Wikimedia projects that use JsonConfig.  Note: Namespace and constant name also used by LinkedWiki
487	Data_talk:	NS_DATA_TALK

NotebookViewer

NotebookViewer

ID	Name	Constant	Remark
486	Notebook:	NS_NOTEBOOK	Jupyter Notebook data

ID 500–599

500–509

BlogPage

BlogPage

ID	Name	Constant	Remark
500	Blog:	NS_BLOG	Extension:MiniInvite adds a minor bit of functionality when this namespace constant is defined (see /includes/MiniInvite.hooks.php).  Note: Namespace and constant name also used by BlueSpice
501	Blog_talk:	NS_BLOG_TALK	Note: Namespace and constant name also used by BlueSpice

SimpleBlogPage

SimpleBlogPage

ID	Name	Constant	Remark
502	User_blog:	NS_USER_BLOG
503	User_blog_talk:	NS_USER_BLOG_TALK

ID 600–699

640–649: EntitySchema

EntitySchema

ID	Name	Constant	Remark
640	EntitySchema:	NS_ENTITYSCHEMA_JSON	Note: Before gerrit:506471, this namespace was named "Schema" with the constant NS_WBSCHEMA_JSON.
641	EntitySchema_talk:	NS_ENTITYSCHEMA_JSON_TALK	Note: Before gerrit:506471 this namespace was named "Schema talk" with the constant NS_WBSCHEMA_JSON_TALK.

ID 700–799

ID 800–899

ID 1000+

1500–1599: BlueSpice

BlueSpice

ID	Name	Constant	Remark
1502	Blog:	NS_BLOG	Note: Namespace and constant name also used by BlogPage
1503	Blog_talk:	NS_BLOG_TALK	Note: Namespace and constant name also used by BlogPage
1504	Book:	NS_BOOK	Provided by Extension:Bookshelf
1505	Book_talk:	NS_BOOK_TALK	Provided by Extension:Bookshelf
1506	SocialEntity:	NS_SOCIALENTITY	Provided by Extension:Social
1507	SocialEntity_talk:	NS_SOCIALENTITY_TALK	Provided by Extension:Social
1530	PROC:	NS_PROC	Provided by Extension:Cognitive Process Designer
1531	PROC_talk:	NS_PROC_TALK	Provided by Extension:Cognitive Process Designer
The Hallo Welt! team would appreciate it if the entire range of 1500–1599 could be reserved for the BlueSpice package.

ID 2000+

2220–2239: VisualData ( formerly PageProperties )

VisualData

ID	Name	Constant	Remark
2220	Data:	NS_DATA	Note: optional manual config Extension:VisualData
2228	VisualDataSchema:	NS_VISUALDATASCHEMA
2229	VisualDataSchema talk:	NS_VISUALDATASCHEMA_TALK
2230	VisualDataQuery:	NS_VISUALDATAQUERY
2231	VisualDataQuery talk:	NS_VISUALDATAQUERY_TALK

ID 3000+: Reserved for sites' custom namespaces

The range of 3000–4999 is reserved for sites to define their custom namespaces without fear of conflict. No known extensions define namespaces in this range; new extensions should also avoid it.

In accordance with this, the NamespaceManager , BlueSpiceNamespaceManager , ManageWiki extensions create custom namespaces using the range from 3000 to 4999.

ID 5000+

ID 7000+

ID 9000+

ID 10,000+

10,000–10,039: LinkedWiki

LinkedWiki

ID	Name	Constant	Remark
10000	Data:	NS_DATA	Note: Constant name also used by JsonConfig
10002	UserData:	NS_USER_DATA
10010	Schema:	NS_SCHEMA	Note: Namespace name also used by EventLogging and (formerly) EntitySchema  Note: Constant name also used by EventLogging
10011	Schema_talk:	NS_SCHEMA_TALK	Note: Namespace name also used by EventLogging and (formerly) EntitySchema  Note: Constant name also used by EventLogging
10030	Datatype:	NS_DATATYPE
10031	Datatype_talk:	NS_DATATYPE_TALK

Archived extensions and removed namespaces

Several extensions that added new namespaces have since been archived, and some namespaces that were added by an extension were later removed; these are listed here since these namespaces may appear in old database dumps from wikis which used these extensions, and some old wikis may continue to use the extensions. It is very strongly recommended to avoid reusing these namespace numbers, as wikis that previously used the old extensions will have log entries etc. related to those pages; however, these numbers can be reserved by new extensions if desired.

Extensions are listed here ordered by the first namespace number they added.

See also

• T33063 – MediaWiki should use a reservation system for namespaces
• Manual:Using custom namespaces
• Localising custom namespaces