Convex with TanStack Start

Loaders and Prefetching

TanStack Start routes can have isomorphic loader functions that run on the server for the initial pageload and on the client for subsequent client-side navigations.

These three links navigate to subpages that show chat messages from different channels. Notice how client navigations between these pages work differently.

Awaiting ensureQueryData will block rendering of the page until that data is available and calling prefetchQuery will start the request but not block. Loaders also run during prefetching, triggered by the cursor mousing onto a link in TanStack Start by default.

When to use a loader

Loading a query in a loader ejects from the convenience of component-local reasoning through useSuspenseQuery where a component fetching its own data to the cold reality of fast page loads when you need it.

2
User 25727/1/25, 2:45 AM

hello Emma! how was your weekend?

1
User 1076/26/25, 2:22 PM

hi Nipunn; how's the weather in SF?

8
User 86846/15/25, 9:56 PM

Hi Emma... how's the weather in SF?

8
User 86846/15/25, 9:55 PM

hey Nipunn- what's your favorite ice cream place?

3
User 37986/2/25, 7:06 PM

Hi Jamie- how was your weekend?

9
User 93835/31/25, 6:52 AM

hi Jamie- Could you let the customer know we've fixed their issue?

9
User 93835/31/25, 6:52 AM

Hi Nipunn, Could you let the customer know we've fixed their issue?

9
User 93835/31/25, 6:51 AM

Hi James! what's your favorite ice cream place?

9
User 93835/31/25, 6:51 AM

Hi James... I'll be late to make the meeting tomorrow morning

9
User 93835/31/25, 6:51 AM

hey Jamie, how was your weekend?

2
User 21545/24/25, 6:32 PM

Hi Jamie! how was your weekend?

6
User 65615/23/25, 6:10 PM

hi Nipunn; how was your weekend?

6
User 65615/23/25, 6:10 PM

Hi Emma- what's your favorite ice cream place?

6
User 65615/23/25, 6:10 PM

hello Nipunn... how's the weather in SF?

6
User 65615/23/25, 6:10 PM

hi Emma, how was your weekend?

6
User 65615/23/25, 6:10 PM

Hi Nipunn- what's your favorite ice cream place?

5
User 50985/15/25, 2:05 AM

hello Nipunn- what's your favorite ice cream place?

6
User 65945/15/25, 2:05 AM

hello James, how's the weather in SF?

6
User 65945/15/25, 2:05 AM

hi Jamie! I'll be late to make the meeting tomorrow morning

6
User 65945/15/25, 2:05 AM

hello Emma- I'll be late to make the meeting tomorrow morning

1export const Route = createFileRoute('/loaders/ensure')({
2  loader: async (opts) => {
3    await opts.context.queryClient.ensureQueryData(
4      convexQuery(api.messages.list, {}),
5    );
6  },
7  component: () => {
8    const { data } = useSuspenseQuery(
9      convexQuery(api.messages.list, {})
10    );
11  },
12})

Learn More

Tanner's An Early Glimpse of TanStack Start video

TanStack Router Preloading Guide