RTK Query Refetch: Practical Tips For Clean Data Updates

When working with modern frontend applications, keeping data in sync with the server without compromising performance or user experience is a constant challenge. This is where RTK Query Refetch plays a pivotal role, allowing developers to control how and when their application communicates with the backend.

In this technical blog, we will examine how to fetch data using RTK Query, control the cache, handle error scenarios, and effectively leverage query hooks, mutation endpoints, and trigger functions. This article aims to demonstrate best practices grounded in real-world experience while adhering to the principles of Redux Toolkit, React Redux, and robust data fetching logic.

What is RTK Query Refetch?

RTK Query is a powerful data fetching and caching tool in the Redux Toolkit. One of its most powerful features is the ability to refetch data from the server when necessary. Whether you're updating cached data, reacting to user interactions, or triggering updates from mutation endpoints, RTK Query provides the flexibility to manage your query lifecycle confidently.

RTK Query refetching allows a component or function to manually or automatically re-run a query to fetch the latest data.

Creating a Reliable RTK Query Setup

1. Create an API Slice

You begin by defining your API slice using createApi from @reduxjs/toolkit/query/react.

1// src/services/postsApi.ts
2import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react';
3
4export const postsApi = createApi({
5  reducerPath: 'postsApi',
6  baseQuery: fetchBaseQuery({ baseUrl: '/api' }),
7  tagTypes: ['Post'],
8  endpoints: (builder) => ({
9    getPosts: builder.query<Post[], void>({
10      query: () => '/posts',
11      providesTags: ['Post'],
12    }),
13    addPost: builder.mutation<void, Post>({
14      query: (post) => ({
15        url: '/posts',
16        method: 'POST',
17        body: post,
18      }),
19      invalidatesTags: ['Post'],
20    }),
21  }),
22});
23
24export const { useGetPostsQuery, useAddPostMutation } = postsApi;

​

This API slice defines both a query endpoint and a mutation endpoint for working with posts.

Understanding Refetching Mechanisms

Manual Refetching via Query Hook

Every query hook returned by createApi provides a refetch function to trigger a refetch data operation manually.

1const { data, error, isLoading, refetch } = useGetPostsQuery();
2
3return (
4  <div>
5    <button onClick={() => refetch()}>Refetch Posts</button>
6    {isLoading && <p>Loading...</p>}
7    {error && <p>Error occurred</p>}
8    <ul>{data?.map(post => <li key={post.id}>{post.title}</li>)}</ul>
9  </div>
10);

​

Automatic Refetching with refetchOnMountOrArgChange

Sometimes you want to re-run a query when the component mounts or the query parameters change.

1const { data } = useGetPostsQuery(undefined, {
2  refetchOnMountOrArgChange: true,
3});

​

This automatically triggers fetches when needed to maintain up-to-date cached data.

Advanced RTK Query Refetch Patterns

Using refetchOnFocus and refetchOnReconnect

Refetch when the page gains focus or when the network reconnects.

1const { data } = useGetPostsQuery(undefined, {
2  refetchOnFocus: true,
3  refetchOnReconnect: true,
4});

​

This provides more flexibility for real-time-like data behavior without polling.

Handling Errors and Request Status

Knowing the status of a query helps provide proper user feedback and control over your UI.

1const { data, isLoading, isError, error, isSuccess } = useGetPostsQuery();
2
3if (isLoading) return <p>Loading...</p>;
4if (isError) return <p>{error.status}: {error.message}</p>;

​

Track request status, handle error gracefully, and avoid rendering inconsistent data.

Cache Invalidation with Mutations

When mutations occur, it's best to invalidate stale cached data.

1const [addPost, { isLoading, error }] = useAddPostMutation();
2
3const onSubmit = async (post: Post) => {
4  await addPost(post);
5};

​

This triggers cache invalidation for the 'Post' tag, causing the getPosts query to automatically refetch the latest data.

How Refetch Works Under the Hood

Mermaid Diagram: Data Flow of Refetch

Testing RTK Query Refetch Behavior

To validate your refetching logic:

1. Simulate user interaction with the refetch button.

2. Inspect Redux store for updated data.

3. Confirm new server responses are returned.

Sample Test Case

1it('refetches posts on button click', async () => {
2  render(<Posts />);
3  fireEvent.click(screen.getByText('Refetch Posts'));
4  expect(await screen.findByText('Post Title 1')).toBeInTheDocument();
5});

​

Utility Techniques for Production

Technique	Purpose	Example
skip	Skip query based on a condition	skip: userId === null
refetchOnMountOrArgChange	Re-run query on arg change	refetchOnMountOrArgChange: true
selectFromResult	Control re-renders with specific data	Select specific part of the query result
trigger	Manually trigger a query	useLazyQuery()

Trigger Function & Lazy Queries

Use trigger for On-Demand Queries

1const [trigger, { data, isLoading }] = useLazyGetPostsQuery();
2
3<button onClick={() => trigger()}>Load Posts</button>

​

This pattern is ideal for pages where fetching occurs only after a user action.

Best Practices Summary

Best Practice	Description
Use refetch to update data manually	Helps with precise control
Handle isLoading, error, and data states explicitly	For clear UX
Invalidate cache with mutations	Keeps cached data in sync
Use refetchOnFocus / refetchOnReconnect sparingly	Avoid excessive fetch overhead
Prefer useLazyQuery for on-demand fetch	Avoids unnecessary loading

Common Pitfalls and How to Avoid Them

• Relying solely on cache: If server data changes, you need a plan for prefetching or cache invalidation.

• Ignoring error boundaries: Always check isError and handle error.response or error.status.

• Overfetching: Using refetchOnMountOrArgChange indiscriminately may cause repeated fetch data operations.

Final Thoughts on RTK Query Refetch

Understanding how to efficiently refetch data using RTK Query can drastically improve your component behavior and user experience. Whether you're building a page that needs to show the most current data, or managing complex interactions between query endpoints, mutations, and the redux store, mastering this behavior ensures your app always shows relevant and accurate data.

By responsibly using trigger functions, fetch logic, and mutation endpoints, you can keep server and client states aligned, maintain clean cached data, and reduce unnecessary fetches.

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