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docs/content/1.get-started/2.usage.md

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+---
+title: Usage
+description: tRPC-Nuxt provides first class integration with tRPC.
+---
+
+# Usage
+
+## Recommended file structure
+
+Recommended but not enforced file structure. This is what you get when starting from [the examples](../main/example-apps.md).
+
+```graphql
+.
+├── server
+│   ├── api
+│   │   └── trpc
+│   │       └── [trpc].ts  # <-- tRPC HTTP handler
+│   │   └── [..]
+│   ├── trpc
+│   │   ├── routers
+│   │   │   ├── index.ts  # <-- main app router
+│   │   │   ├── todo.ts  # <-- sub routers
+│   │   │   └── [..]
+│   │   ├── context.ts   # <-- create app context
+│   │   └── trpc.ts      # <-- procedure helpers
+├── plugins
+│   ├── client.ts  # <-- tRPC Client as a plugin
+└── [..]
+```
+
+## 1. Create a tRPC router
+
+Initialize your tRPC backend using the `initTRPC` function and create your first router.
+
+::code-group
+
+```ts [server/trpc/trpc.ts]
+import { TRPCError, initTRPC } from '@trpc/server'
+
+// Avoid exporting the entire t-object since it's not very
+// descriptive and can be confusing to newcomers used to t
+// meaning translation in i18n libraries.
+const t = initTRPC.create()
+
+// Base router and procedure helpers
+export const router = t.router
+export const publicProcedure = t.procedure
+```
+
+```ts [server/trpc/routers/index.ts]
+import { z } from 'zod'
+import { publicProcedure, router } from '..'
+
+export const appRouter = router({
+  hello: publicProcedure
+    .input(
+      z.object({
+        text: z.string().nullish(),
+      }),
+    )
+    .query(({ input }) => {
+      return {
+        greeting: `hello ${input?.text ?? 'world'}`,
+      }
+    }),
+})
+
+// export type definition of API
+export type AppRouter = typeof appRouter
+```
+
+```ts [server/api/trpc/[trpc].ts]
+import { createNuxtApiHandler } from 'trpc-nuxt'
+import { appRouter } from '../../trpc/routers'
+
+// export API handler
+export default createNuxtApiHandler({
+  router: appRouter,
+  createContext: () => ({}),
+})
+```
+
+::
+
+::alert{type=info}
+If you need to split your router into several subrouters, you can implement them in the `server/trpc/routers` directory and import and [merge them](https://trpc.io/docs/v10/merging-routers) to a single root `appRouter`.
+::
+
+## 2. Create tRPC client plugin
+
+Create a set of strongly-typed composables using your API's type signature.
+
+```ts [plugins/client.ts]
+import { httpBatchLink } from '@trpc/client'
+import { createTRPCNuxtProxyClient } from 'trpc-nuxt/client'
+import type { AppRouter } from '~~/server/trpc/routers'
+
+export default defineNuxtPlugin(() => {
+  const client = createTRPCNuxtProxyClient<AppRouter>({
+    links: [
+      httpBatchLink({
+        /**
+         * If you want to use SSR, you need to use the server's full URL
+         * @link https://trpc.io/docs/ssr
+         **/
+        url: 'http://localhost:3000/api/trpc',
+      }),
+    ],
+  })
+
+  return {
+    provide: {
+      client,
+    },
+  }
+})
+```
+
+## 3. Make API requests
+
+```vue [pages/index.vue]
+<script setup lang="ts">
+const { $client } = useNuxtApp()
+
+// query and mutate uses useAsyncData under the hood
+const { data, pending, error } = await $client.hello.query({ text: 'client' })
+</script>
+
+<template>
+  <div v-if="pending">
+    Loading...
+  </div>
+  <div v-else-if="error?.data?.code">
+    Error: {{ error.data.code }}
+  </div>
+  <div v-else>
+    <p>{{ hello.data?.greeting }}</p>
+  </div>
+</template>
+```