diff --git a/lib/app/Content.js b/lib/app/components/Content.js
similarity index 85%
rename from lib/app/Content.js
rename to lib/app/components/Content.js
index 6d76ef4b..1b3909be 100644
--- a/lib/app/Content.js
+++ b/lib/app/components/Content.js
@@ -1,7 +1,8 @@
 import { h, shallowRef, watchEffect, inject, nextTick } from 'vue'
-import { RouteSymbol } from './router'
+import { RouteSymbol } from '../composables/router'
+import Theme from '/@theme/index'
 
-const Default404 = () => '404 Not Found'
+const NotFound = Theme.NotFound || (() => '404 Not Found')
 
 export const Content = {
   setup() {
@@ -35,7 +36,7 @@ export const Content = {
           })
           .catch((err) => {
             if (route.path === pendingPath) {
-              comp.value = Default404
+              comp.value = NotFound
             }
           })
       })
diff --git a/lib/app/composables/data.js b/lib/app/composables/data.js
new file mode 100644
index 00000000..a2c575b9
--- /dev/null
+++ b/lib/app/composables/data.js
@@ -0,0 +1,11 @@
+export function useSiteData() {
+  return {
+    msg: 'this is site'
+  }
+}
+
+export function usePageData() {
+  return {
+    msg: 'this is page'
+  }
+}
diff --git a/lib/app/router.js b/lib/app/composables/router.js
similarity index 100%
rename from lib/app/router.js
rename to lib/app/composables/router.js
diff --git a/lib/app/exports.js b/lib/app/exports.js
new file mode 100644
index 00000000..b21a1942
--- /dev/null
+++ b/lib/app/exports.js
@@ -0,0 +1,3 @@
+// exports in this file are exposed to themes and md files via 'vitepress'
+// so the user can do `import { usePageData } from 'vitepress'`
+export { usePageData, useSiteData } from './composables/data'
diff --git a/lib/app/index.js b/lib/app/index.js
index 5267b384..83753d74 100644
--- a/lib/app/index.js
+++ b/lib/app/index.js
@@ -1,7 +1,8 @@
 import { createApp, h } from 'vue'
-import { Layout } from '/@theme/index'
-import { Content } from './Content'
-import { useRouter } from './router'
+import { Content } from './components/Content'
+import { useRouter } from './composables/router'
+import { useSiteData } from './composables/data'
+import Theme from '/@theme/index'
 
 const App = {
   setup() {
@@ -10,12 +11,16 @@ const App = {
     } else {
       // TODO inject static route for SSR
     }
-    return () => h(Layout)
+    return () => h(Theme.Layout)
   }
 }
 
 const app = createApp(App)
 
+Object.defineProperty(app.config.globalProperties, '$site', {
+  get: useSiteData
+})
+
 app.component('Content', Content)
 
 app.mount('#app')
diff --git a/lib/jsconfig.json b/lib/jsconfig.json
index 6f38c88b..7176ac8c 100644
--- a/lib/jsconfig.json
+++ b/lib/jsconfig.json
@@ -1,5 +1,6 @@
 {
   "compilerOptions": {
+    "baseUrl": "../",
     "lib": ["ESNext", "DOM"],
     "moduleResolution": "node",
     "checkJs": true,
@@ -8,7 +9,8 @@
     "noImplicitAny": true,
     "paths": {
       "/@app/*": ["lib/app/*"],
-      "/@theme/*": ["lib/theme-default/*"]
+      "/@theme/*": ["lib/theme-default/*"],
+      "vitepress": ["lib/app/exports.js"]
     }
   },
   "include": ["."]
diff --git a/lib/theme-default/Layout.vue b/lib/theme-default/Layout.vue
index dc01f311..54dd80e1 100644
--- a/lib/theme-default/Layout.vue
+++ b/lib/theme-default/Layout.vue
@@ -1,13 +1,22 @@
 <template>
   <div class="theme-container">
-    <h1>Hello VitePress {{ a }}</h1>
+    <h1>Hello VitePress</h1>
+    <pre>{{ $site }}</pre>
+    <pre>{{ $page }}</pre>
+    <pre>{{ site }}</pre>
+    <pre>{{ page }}</pre>
     <Content/>
   </div>
 </template>
 
 <script>
+import { useSiteData, usePageData } from 'vitepress'
+
 export default {
-  data: () => ({ a: 111 })
+  data: () => ({
+    site: useSiteData(),
+    page: usePageData()
+  })
 }
 </script>
 
diff --git a/lib/theme-default/index.js b/lib/theme-default/index.js
index 4763bbc2..964ac493 100644
--- a/lib/theme-default/index.js
+++ b/lib/theme-default/index.js
@@ -1,3 +1,13 @@
 import Layout from './Layout.vue'
 
-export { Layout }
+/**
+ * @type {{
+ *   Layout: import('vue').ComponentOptions
+ *   NotFound?: import('vue').ComponentOptions
+ * }}
+ */
+const Theme = {
+  Layout
+}
+
+export default Theme
diff --git a/src/server.ts b/src/server.ts
index 0b39e6c7..c3567d79 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -38,7 +38,7 @@ function createVitePressPlugin({
     app.use(async (ctx, next) => {
       // handle .md -> vue transforms
       if (ctx.path.endsWith('.md')) {
-        const file = resolver.publicToFile(ctx.path)
+        const file = resolver.requestToFile(ctx.path)
         await cachedRead(ctx, file)
         // let vite know this is supposed to be treated as vue file
         ctx.vue = true
@@ -48,7 +48,7 @@ function createVitePressPlugin({
       }
 
       // detect and serve vitepress @app / @theme files
-      const file = vitepressResolver.publicToFile(ctx.path, root)
+      const file = vitepressResolver.requestToFile(ctx.path, root)
       if (file) {
         await cachedRead(ctx, file)
         debug(ctx.url, ctx.status)
diff --git a/src/tsconfig.json b/src/tsconfig.json
index a045e381..f87a6b82 100644
--- a/src/tsconfig.json
+++ b/src/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "baseUrl": ".",
+    "baseUrl": "../",
     "outDir": "../dist",
     "module": "commonjs",
     "lib": ["ESNext"],
diff --git a/src/utils/pathResolver.ts b/src/utils/pathResolver.ts
index 81cf023d..7b4ef089 100644
--- a/src/utils/pathResolver.ts
+++ b/src/utils/pathResolver.ts
@@ -10,7 +10,7 @@ export const APP_PATH = path.join(__dirname, '../../lib/app')
 // vite HMR can send the correct update notifications to the client.
 export function createResolver(themePath: string): Resolver {
   return {
-    publicToFile(publicPath) {
+    requestToFile(publicPath) {
       if (publicPath.startsWith('/@app')) {
         return path.join(APP_PATH, publicPath.replace(/^\/@app\/?/, ''))
       }
@@ -18,13 +18,18 @@ export function createResolver(themePath: string): Resolver {
         return path.join(themePath, publicPath.replace(/^\/@theme\/?/, ''))
       }
     },
-    fileToPublic(filePath) {
+    fileToRequest(filePath) {
       if (filePath.startsWith(APP_PATH)) {
         return `/@app/${path.relative(APP_PATH, filePath)}`
       }
       if (filePath.startsWith(themePath)) {
         return `/@theme/${path.relative(themePath, filePath)}`
       }
+    },
+    idToRequest(id) {
+      if (id === 'vitepress') {
+        return '/@app/exports.js'
+      }
     }
   }
 }