First release. query_kit is a Dart port of TanStack Query's query-core: a cache for server state with no Flutter dependency. The Flutter binding is query_kit_flutter. From here on, a breaking change is a major version.

query_kit is an entirely AI-coded project: all code, tests and documentation were written by AI coding agents (Anthropic's Claude). A human maintainer set the goals and reviews releases, but did not write the code. It is a community port, not affiliated with or endorsed by TanStack.

Queries

• QueryClient with a QueryCache: caching by QueryKey, staleTime and gcTime, request deduplication, retries with backoff (RetryPolicy, RetryDelay) and cancellation through QueryCancelToken.
• QueryObserver for reactive reads, with sealed QueryResults (QueryPending, QuerySuccess, QueryError carrying the last good data).
• Refetching on focus, on reconnect, on an interval (RefetchInterval) and after invalidateQueries; Enabled for dependent and lazy queries.
• select, InitialData, PlaceholderData (including PlaceholderData.keepPrevious()) and structural sharing, extendable to your own classes with StructurallyShareable.
• QueryClient.query for imperative reads — fetch, prefetch, "ensure" and stale-while-revalidate in one method.
• getQueryData, setQueryData, updateQueryData, cancelQueries, refetchQueries, resetQueries, removeQueries, QueryFilters, and per-key defaults through setQueryDefaults.
• consecutiveErrorCount on every result, so polling can give up after N failures.

Mutations

• MutationObserver and MutationCache, with onMutate, onSuccess, onError and onSettled, optimistic updates and rollback.
• MutationOptions.simple for mutations without an optimistic step; mutationFnWithContext and cancel() for cancellable mutations.
• MutationScope to run writes one after another; paused mutations resume when the client is back online (resumePausedMutations).
• MutationStateObserver for cache-wide mutation state, isMutating.

Infinite queries

• InfiniteQueryObserver with fetchNextPage, fetchPreviousPage, hasNextPage and maxPages, over a typed InfinitePageContext.

Collections

• QueriesObserver for a dynamic list of queries, and combine over a record or a list of results (CombinedResult, CombineMemo, optional(), combineWith).

Dart-first design

• Sealed option values (StaleTime, GcTime, Enabled, RetryPolicy, RefetchOn, RefetchInterval, …) instead of magic numbers.
• QueryKey is a value type; a key is bound to one data type and a mismatched read throws QueryDataTypeError.
• AppFocusManager, OnlineManager and NotifyManager owned per client; time goes through package:clock, so fake_async controls every timer.

Not in this release: persistence and hydration, streamedQuery, server-side rendering, devtools.