This skill builds on [react-query-setup]. Read it first for foundational concepts.

tRPC -- Classic React Query Migration

Overview

This skill covers migrating from @trpc/react-query (the classic tRPC React hooks) to @trpc/tanstack-react-query (the new options-factory client). The two packages can coexist in the same application, so you can migrate incrementally.

Step 1: Run the upgrade CLI

npx @trpc/upgrade

When prompted, select:

• Migrate Hooks to queryOptions/mutationOptions API
• Migrate context provider setup

The codemod handles common patterns but is a work in progress. Always typecheck after running it.

Step 2: Install the new package

npm install @trpc/tanstack-react-query

You can keep @trpc/react-query installed during the migration period.

Step 3: Set up the new provider

Replace the classic createTRPCReact setup with createTRPCContext:

// BEFORE (classic)
import { createTRPCReact } from '@trpc/react-query';
import type { AppRouter } from '../server/router';
export const trpc = createTRPCReact<AppRouter>();

// AFTER (new)
import { createTRPCContext } from '@trpc/tanstack-react-query';
import type { AppRouter } from '../server/router';
export const { TRPCProvider, useTRPC } = createTRPCContext<AppRouter>();

Update the provider in your app root:

// BEFORE (classic)

// trpc.Provider wrapping with queryClient and client props

// AFTER (new)
import { QueryClientProvider } from '@tanstack/react-query';
import { TRPCProvider } from '../utils/trpc';

<QueryClientProvider client={queryClient}>
  <TRPCProvider trpcClient={trpcClient} queryClient={queryClient}>
    {children}
  </TRPCProvider>
</QueryClientProvider>;

Migration Patterns

Queries

// BEFORE (classic)
import { trpc } from './trpc';

function Users() {
  const greeting = trpc.greeting.useQuery({ name: 'Jerry' });
}

// AFTER (new)
import { useQuery } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();
  const greeting = useQuery(trpc.greeting.queryOptions({ name: 'Jerry' }));
}

Mutations

// BEFORE (classic)
import { trpc } from './trpc';

function Users() {
  const createUser = trpc.createUser.useMutation();
  createUser.mutate({ name: 'Jerry' });
}

// AFTER (new)
import { useMutation } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();
  const createUser = useMutation(trpc.createUser.mutationOptions());
  createUser.mutate({ name: 'Jerry' });
}

Query invalidation

// BEFORE (classic)
import { trpc } from './trpc';

function Users() {
  const utils = trpc.useUtils();
  async function invalidateGreeting() {
    await utils.greeting.invalidate({ name: 'Jerry' });
  }
}

// AFTER (new)
import { useQueryClient } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();
  const queryClient = useQueryClient();
  async function invalidateGreeting() {
    await queryClient.invalidateQueries(
      trpc.greeting.queryFilter({ name: 'Jerry' }),
    );
  }
}

Other QueryClient operations

Any classic trpc.useUtils() usage maps to standard TanStack Query useQueryClient() calls:

Classic (utils.xxx)	New (queryClient + trpc)
utils.post.invalidate()	queryClient.invalidateQueries(trpc.post.queryFilter())
utils.post.refetch()	queryClient.refetchQueries(trpc.post.queryFilter())
utils.post.getData(input)	queryClient.getQueryData(trpc.post.byId.queryKey(input))
utils.post.setData(input,d)	queryClient.setQueryData(trpc.post.byId.queryKey(input),d)

Step 4: Typecheck and fix

After migrating all files (or a batch of files), run TypeScript to catch remaining issues:

npx tsc --noEmit

Common type errors after migration:

• Missing useTRPC() call (the new pattern requires calling the hook inside the component)
• Incorrect options shape (queryOptions takes the procedure input as the first arg; mutationOptions takes TanStack Query options like onSuccess/onError, with mutation variables passed later to mutate(...))
• useUtils() references that need to become useQueryClient() + useTRPC() pairs

Step 5: Remove classic package

Once all files are migrated and TypeScript passes:

npm uninstall @trpc/react-query

Common Mistakes

Assuming the codemod handles everything

npx @trpc/upgrade is a work-in-progress codemod. It handles common patterns but may miss complex cases like dynamic query keys, conditional hooks, or custom wrappers around tRPC hooks. Always run tsc --noEmit after the codemod completes and fix remaining errors manually.

Mixing classic and new hooks in the same component

While the classic and new packages can coexist in the same app, mixing their hooks in the same component creates confusing dual-provider requirements and makes the code harder to reason about. Migrate one component at a time, converting all hooks in that component from classic to new in a single pass.

See Also

• [react-query-setup] -- full setup guide for the new @trpc/tanstack-react-query package
• [nextjs-app-router] -- if migrating a Next.js app to App Router at the same time