How can you integrate RTK Query with server-side rendering (SSR)?

RTK Query supports Server-Side Rendering (SSR) by allowing you to prefetch data on the server before rendering the page. This ensures that the client receives fully populated state and avoids redundant refetching on load.

Steps to Integrate RTK Query with SSR

1
Create and Configure the Store on the Server: Use configureStore with your api slice and other reducers.
2
Prefetch Required Data Using api.endpoints.<endpoint>.initiate(): Dispatch query initiations on the server to populate the store with data.
3
Wait for All Queries to Resolve: Use Promise.all or store.dispatch(api.util.getRunningQueriesThunk()) to ensure all requests complete before rendering.
4
Serialize and Hydrate the Store State: Send the preloaded Redux state to the client and hydrate it using hydrate or standard Redux store initialization.

Example: SSR with RTK Query in Next.js

In this example, getServerSideProps prefetches the data using getUsers before rendering. When the client loads, it reuses the hydrated cache and avoids refetching.

Benefits of SSR with RTK Query

1
- Faster Initial Page Load: Data is available immediately when the page is rendered.
2
- SEO-Friendly Rendering: Search engines can crawl pages with pre-fetched data.
3
- Reduced Client Fetching: Avoids redundant API requests on the client side.

RTK Query’s SSR support makes it easy to combine the power of Redux with server-rendered applications like Next.js, providing both performance and SEO benefits.

Difficulty: 8/10

Topics: SSR integration, prefetching, cache hydration

Scenario Questions

0-2 years experience

1
How would you fetch data with RTK Query in a Next.js page that uses getServerSideProps?
2
What steps are needed to make sure the data fetched on the server is available to the client without a second request?
3
If you forget to pass the preloaded state to the client store, what would the UI show?

2-5 years experience

1
You added an RTK Query prefetch in getStaticProps but the page still makes a network request on the client. What could be causing that?
2
Explain the trade‑offs between using getServerSideProps versus getStaticProps with RTK Query for a news feed that updates frequently.
3
During a rollout you notice the server‑side cache growing unbounded. How would you debug and fix it?

5-8 years experience

1
Design a solution to share the RTK Query cache across multiple Next.js pages while keeping SSR consistency and avoiding stale data.
2
How would you handle authentication tokens that are only available on the client when using RTK Query with SSR?
3
What performance considerations would you evaluate when prefetching many endpoints on the server for a dashboard?

8+ years experience

1
If your organization is migrating a large legacy codebase from custom data fetching to RTK Query with SSR, what migration strategy would you propose to minimize risk?
2
Discuss how you would structure shared store and API slices across several micro‑frontends that each need SSR support.
3
How would you set up automated testing to verify that server‑side data hydration works correctly across environments?

Follow-up Questions

❓Can you sketch the code you’d write for the server‑side prefetch?
❓What edge cases could cause the client to refetch the data?
❓How would you measure the performance impact of this approach?