[Mediawiki-api-announce] Planned removal of api_urls field in /page/summary endpoint
This message is a notice about forthcoming removal of a response field in the REST API’s /page/summary endpoint.  This message was posted to wikitech-l and is being cross-posted on mediawiki-api-announce.
The endpoint is used in the Page Previews (“hovercards”) functionality on the classic web (desktop) and Android & iOS experiences for Wikipedia, in addition to numerous external experiences. We don't anticipate impacts on the mainline Wikipedia experiences from this forthcoming field removal, as the endpoint will still be operational.
The REST API's /page/summary endpoint provides an api_urls field in its response with links to several other REST API endpoints supported by the Page Content Service.
Three of the api_urls subfields refer to experimental endpoints that have been removed from the REST API altogether in favor of newer API endpoints.
1. media (/page/media) 2. references (/page/references) 3. metadata (/page/metadata).
api_urls also contains subfields referring to stable endpoints that continue to exist in the REST API:
1. summary (which is self referential) 2. edit_html (/page/html - the Parsoid HTML) 3. talk_html (/page/html/Talk:<title> - the Parsoid HTML for the corresponding Talk page)
Wikimedia’s Product Infrastructure team intends to remove the api_urls field of the /page/summary response.
Review of web logs suggests traffic for the following endpoints:
- The media endpoint is at about 5% of its original traffic before its decommission and it appears to be from old Wikipedia for Android clients. This is expected. - The references endpoint’s Wikipedia for Android traffic does not seem present and its other traffic appears to be from non-user application software based on User-Agent header components. -The metadata endpoint’s traffic seems to have all but stopped.
This change is being announced in advance of the change because the endpoint is advertised as stable. 
Please update your clients if you rely on the presence of the api_urls field. If this change poses a problem for your clients, please do let us know as soon as possible at the tracking task: