TanStack Query Best Practices

Comprehensive guidelines for implementing TanStack Query (React Query) patterns in React applications. These rules optimize data fetching, caching, mutations, and server state synchronization.

When to Apply

• Creating new data fetching logic
• Setting up query configurations
• Implementing mutations and optimistic updates
• Configuring caching strategies
• Integrating with SSR/SSG
• Refactoring existing data fetching code

Rule Categories by Priority

Priority	Category	Rules	Impact
CRITICAL	Query Keys	5 rules	Prevents cache bugs and data inconsistencies
CRITICAL	Caching	5 rules	Optimizes performance and data freshness
HIGH	Mutations	6 rules	Ensures data integrity and UI consistency
HIGH	Error Handling	3 rules	Prevents poor user experiences
MEDIUM	Prefetching	4 rules	Improves perceived performance
MEDIUM	Parallel Queries	2 rules	Enables dynamic parallel fetching
MEDIUM	Infinite Queries	3 rules	Prevents pagination bugs
MEDIUM	SSR Integration	4 rules	Enables proper hydration
LOW	Performance	4 rules	Reduces unnecessary re-renders
LOW	Offline Support	2 rules	Enables offline-first patterns

Quick Reference

Query Keys (Prefix: qk-)

• qk-array-structure — Always use arrays for query keys
• qk-include-dependencies — Include all variables the query depends on
• qk-hierarchical-organization — Organize keys hierarchically (entity → id → filters)
• qk-factory-pattern — Use query key factories for complex applications
• qk-serializable — Ensure all key parts are JSON-serializable

Caching (Prefix: cache-)

• cache-stale-time — Set appropriate staleTime based on data volatility
• cache-gc-time — Configure gcTime for inactive query retention
• cache-defaults — Set sensible defaults at QueryClient level
• cache-invalidation — Use targeted invalidation over broad patterns
• cache-placeholder-vs-initial — Understand placeholder vs initial data differences

Mutations (Prefix: mut-)

• mut-invalidate-queries — Always invalidate related queries after mutations
• mut-optimistic-updates — Implement optimistic updates for responsive UI
• mut-rollback-context — Provide rollback context from onMutate
• mut-error-handling — Handle mutation errors gracefully
• mut-loading-states — Use isPending for mutation loading states
• mut-mutation-state — Use useMutationState for cross-component tracking

Error Handling (Prefix: err-)

• err-error-boundaries — Use error boundaries with useQueryErrorResetBoundary
• err-retry-config — Configure retry logic appropriately
• err-fallback-data — Provide fallback data when appropriate

Prefetching (Prefix: pf-)

• pf-intent-prefetch — Prefetch on user intent (hover, focus)
• pf-route-prefetch — Prefetch data during route transitions
• pf-stale-time-config — Set staleTime when prefetching
• pf-ensure-query-data — Use ensureQueryData for conditional prefetching

Infinite Queries (Prefix: inf-)

• inf-page-params — Always provide getNextPageParam
• inf-loading-guards — Check isFetchingNextPage before fetching more
• inf-max-pages — Consider maxPages for large datasets

SSR Integration (Prefix: ssr-)

• ssr-dehydration — Use dehydrate/hydrate pattern for SSR
• ssr-client-per-request — Create QueryClient per request
• ssr-stale-time-server — Set higher staleTime on server
• ssr-hydration-boundary — Wrap with HydrationBoundary

Parallel Queries (Prefix: parallel-)

• parallel-use-queries — Use useQueries for dynamic parallel queries
• query-cancellation — Implement query cancellation properly

Performance (Prefix: perf-)

• perf-select-transform — Use select to transform/filter data
• perf-structural-sharing — Leverage structural sharing
• perf-notify-change-props — Limit re-renders with notifyOnChangeProps
• perf-placeholder-data — Use placeholderData for instant UI

Offline Support (Prefix: offline-)

• network-mode — Configure network mode for offline support
• persist-queries — Configure query persistence for offline support

How to Use

Each rule file in the rules/ directory contains:

1. Explanation — Why this pattern matters
2. Bad Example — Anti-pattern to avoid
3. Good Example — Recommended implementation
4. Context — When to apply or skip this rule

Full Reference

See individual rule files in rules/ directory for detailed guidance and code examples.