API reference
The field-level pages are generated from the declarations, so they always match what ships; each field's semantics, deprecations and parameter constraints live in its JSDoc, both here and on hover in your IDE.
Concepts — the response envelope and error handling, paging through query results, narrowing query.pages with QueryPage, reading log event details, how field types map to the wire format, activating extension packs — are covered in the guide. This tree is the field-level reference.
Core
Everything MediaWiki core can return: the response envelope (ApiEnvelope, ApiResponseWith), shared atoms (Flag, Timestamp …), one response type per action= (ApiQueryResponse, ApiEditResponse …), and the action=query framework — ApiPage, ApiQueryResult, the QueryPage projection, per-module continue tokens (ApiQueryContinue) and the per-action structured log details of ApiLogEventParams.
Each single-module action= maps to one response type:
Browse the full Core reference.
Extension packs
Extension responses are opt-in: each pack lives at the subpath types-mediawiki-response/ext/<name> and is activated by a single type-only import — see Opt-in extension packs. Packs for query sub-modules merge their fields into the shared ApiPage / ApiQueryResult; packs for extension actions export standalone response types to import type directly.