Changed

• All APIs - Begin Phase 2 enforcement of API Rate Limiting. Identified requests are now also subject to rate limits. Bots running in Toolforge/Wikimedia Cloud Services or with the bot user right on any wiki should not be affected. More information is available on the WE5.1 project page. (Week of April 28)

Added

• Attribution API - Launch Attribution API (beta). The beta period will last at least 3 months before promoting the API to a v1. More information can be found on the Attribution API project page; users may also provide feedback and request feature enhancements on the project discussion page, or file bugs directly through the MediaWiki Interfaces Phabricator board. (April 20, T419545)

Removed

Fixed

Changed

• All APIs - Announce and begin Phase 1 enforcement of API Rate Limiting. More information available on the WE5.1 project page. (March 12, T412585)
• MediaWiki REST API - Begin creating REST API modules for extension APIs. REST API modules represent individually managed and versioned sets of related endpoints. Module designations can be viewed through the REST Sandbox and include:
  • Growth experiments (T414470)
  • Wikifunctions (T419053)
• api.wikimedia.org APIs - Transition APIs available through api.wikimedia.org to the new rate limits. This change does not apply to the Lift Wing API. (March 31, phab:T413438)

Removed

• Action API - Deprecation Announce deprecation of format=php (March 31st). This format remains functional, but will be sunset on May 1st, 2026. API users should transition to use the JSON format. (T118538)

Changed

• Link Recommendation API - Move documentation from the API Portal to mediawiki.org as part of API Portal deprecation. (February 5, T415312)
• Page Description API - Move documentation from the API Portal to mediawiki.org as part of API Portal deprecation. (February 5, T415686)
• Wikifunctions API - Move documentation from the API Portal to mediawiki.org as part of API Portal deprecation. (February 18, T415310)

Changed

• Wikimedia REST API - Move interactive reference documentation for the Wikimedia REST API. Requests to API docs previously hosted through RESTBase (e.g.: https://en.wikipedia.org/api/rest_v1/) are now redirected to the REST Sandbox special page (e.g.: Special:RestSandbox).
• Wikimedia REST API - Move the Math API to a separate OpenAPI description. It’s now hosted through wikimedia.org instead of the standard per-wiki path. (Week of January 12, T411517)
• Wikimedia REST API - Deprecation Mark per-wiki Math endpoints as deprecated. Math endpoints hosted through wikimedia.org instead of per-wiki paths are the preferred path. These endpoints remain functional, with an expected removal date to be an announced (no sooner than September 2026).

Removed

• MediaWiki REST API - Breaking Sunset and remove support for Transform endpoints reflecting the trailing slash implementation pattern. You can use non-trailing slash versions instead. (Week of January 26, T404855)

Changed

• Action API - Expose the list of domains supported by the upload-by-URL feature via meta=siteinfo. (December 8, T396049)
• Action API - Deprecate the parsoid parameter to action=parse. Use parser=parsoid instead. (December 8, T399897)
• MediaWiki REST API - Revise and restructure on-wiki API documentation, including a complete overhaul of API:REST API and Template:REST API, and the addition of two new pages: API:REST API/Get started and API:REST API/Policies. (Week of December 8, T405972)

Removed

• Action API - Breaking Remove support for XSLT style sheets (format=xml&xlst={stylesheet}) in all Wikimedia projects. Stylesheets will also be disabled by default in MediaWiki release versions: v1.43 (LTS), v1.44, and v1.45. Support for XSLT stylesheets will be fully removed from MediaWiki v1.46 (expected to release between April and May 2026).

Changed

• MediaWiki REST API - Deprecation Mark trailing slash Transform endpoints as deprecated. These endpoints remain functional, but will be removed by the end of January, 2026. (Announced in the week of October 13)
  • For more information about Wikimedia API deprecation policies and procedures, see API/Deprecation.
  • For more information about removing the trailing slash endpoints specifically, see T404855.

Added

• MediaWiki REST API - Launch REST Sandbox on all wiki projects. You can now access the REST API sandbox through the Special:RestSandbox page on any wiki. (October 20)