diff --git a/fixtures/blocks/src/Router.js b/fixtures/blocks/src/Router.js
index 50f93d9d34..63e15aabfa 100644
--- a/fixtures/blocks/src/Router.js
+++ b/fixtures/blocks/src/Router.js
@@ -15,17 +15,16 @@ import React, {
 } from 'react';
 import {createCache, CacheProvider} from 'react/unstable-cache';
 import {RouterProvider} from './client/RouterContext';
-// TODO: entry point. This can't really done in the client code.
-import loadApp from './server/App.block';
+// TODO: can't really import a server component on the client.
+import App from './server/App';
 
 const initialUrl = window.location.pathname;
-
 const initialState = {
   // TODO: use this for invalidation.
   cache: createCache(),
   url: initialUrl,
   pendingUrl: initialUrl,
-  RootBlock: loadApp(initialUrl),
+  root: <App route={initialUrl} />,
 };
 
 function reducer(state, action) {
@@ -41,7 +40,7 @@ function reducer(state, action) {
         ...state,
         url: action.url,
         pendingUrl: action.url,
-        RootBlock: action.RootBlock,
+        root: action.root,
       };
     default:
       throw new Error();
@@ -65,7 +64,7 @@ function Router() {
         // TODO: Instant Transitions, somehow.
         dispatch({
           type: 'completeNavigation',
-          RootBlock: loadApp(url),
+          root: <App route={url} />,
           url,
         });
       });
@@ -97,9 +96,7 @@ function Router() {
   return (
     <Suspense fallback={<h2>Loading...</h2>}>
       <CacheProvider value={state.cache}>
-        <RouterProvider value={routeContext}>
-          <state.RootBlock />
-        </RouterProvider>
+        <RouterProvider value={routeContext}>{state.root}</RouterProvider>
       </CacheProvider>
     </Suspense>
   );
diff --git a/fixtures/blocks/src/client/ProfileNav.js b/fixtures/blocks/src/client/ProfileNav.js
new file mode 100644
index 0000000000..0eeb104afe
--- /dev/null
+++ b/fixtures/blocks/src/client/ProfileNav.js
@@ -0,0 +1,21 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+
+import {TabBar, TabLink} from '../client/TabNav';
+
+export default function ProfileNav({userId}) {
+  // TODO: Don't hardcode ID.
+  return (
+    <TabBar>
+      <TabLink to={`/profile/${userId}`}>Timeline</TabLink>
+      <TabLink to={`/profile/${userId}/bio`}>Bio</TabLink>
+    </TabBar>
+  );
+}
diff --git a/fixtures/blocks/src/server/App.block.js b/fixtures/blocks/src/server/App.block.js
deleted file mode 100644
index a02cedd3ce..0000000000
--- a/fixtures/blocks/src/server/App.block.js
+++ /dev/null
@@ -1,44 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-/* eslint-disable import/first */
-
-import * as React from 'react';
-import {unstable_block as block} from 'react';
-
-// Server
-
-import loadFeedPage from './FeedPage.block';
-import loadProfilePage from './ProfilePage.block';
-
-function load(url) {
-  let Page;
-  const segments = url.split('/').filter(Boolean);
-  if (segments.length === 0) {
-    Page = loadFeedPage();
-  } else if (segments[0] === 'profile') {
-    Page = loadProfilePage(Number(segments[1]), segments[2]);
-  } else {
-    throw Error('Not found');
-  }
-  return {Page};
-}
-
-// Client
-
-import Shell from '../client/Shell';
-
-// TODO: some notion of key.
-
-function App(props, data) {
-  return (
-    <Shell>
-      <data.Page />
-    </Shell>
-  );
-}
-
-export default block(App, load);
diff --git a/fixtures/blocks/src/server/App.js b/fixtures/blocks/src/server/App.js
new file mode 100644
index 0000000000..792e1f7c76
--- /dev/null
+++ b/fixtures/blocks/src/server/App.js
@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {matchRoute} from './ServerRouter';
+import FeedPage from './FeedPage';
+import ProfilePage from './ProfilePage';
+
+// TODO: Replace with asset reference.
+import loadShell from './Shell.block';
+
+// TODO: Router component?
+const AppRoutes = {
+  '/': props => <FeedPage {...props} key="home" />,
+  '/profile/:userId/*': props => (
+    <ProfilePage {...props} key={`profile-${props.userId}`} />
+  ),
+};
+
+export default function App(props) {
+  const Shell = loadShell();
+  const match = matchRoute(props, AppRoutes);
+  return <Shell>{match}</Shell>;
+}
diff --git a/fixtures/blocks/src/server/Comments.block.js b/fixtures/blocks/src/server/Comments.js
similarity index 62%
rename from fixtures/blocks/src/server/Comments.block.js
rename to fixtures/blocks/src/server/Comments.js
index 2bc4d518c8..14f37f6a99 100644
--- a/fixtures/blocks/src/server/Comments.block.js
+++ b/fixtures/blocks/src/server/Comments.js
@@ -7,28 +7,19 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {unstable_block as block} from 'react';
-
-// Server
-
 import {fetch} from 'react-data/fetch';
 
-function load(postId) {
-  return {
-    comments: fetch(`/comments?postId=${postId}&_expand=user`).json(),
-  };
-}
+// TODO: Replace with asset reference.
+import loadLink from './Link.block';
 
-// Client
-
-import Link from '../client/Link';
-
-function Comments(props, data) {
+export default function Comments({postId}) {
+  const Link = loadLink();
+  const comments = fetch(`/comments?postId=${postId}&_expand=user`).json();
   return (
     <>
       <h5>Comments</h5>
       <ul>
-        {data.comments.slice(0, 5).map(comment => (
+        {comments.slice(0, 5).map(comment => (
           <li key={comment.id}>
             {comment.body}
             {' • '}
@@ -39,5 +30,3 @@ function Comments(props, data) {
     </>
   );
 }
-
-export default block(Comments, load);
diff --git a/fixtures/blocks/src/server/FeedPage.block.js b/fixtures/blocks/src/server/Feed.js
similarity index 56%
rename from fixtures/blocks/src/server/FeedPage.block.js
rename to fixtures/blocks/src/server/Feed.js
index 82bfa57b4e..f00c5fff7e 100644
--- a/fixtures/blocks/src/server/FeedPage.block.js
+++ b/fixtures/blocks/src/server/Feed.js
@@ -7,29 +7,15 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {unstable_block as block} from 'react';
 import {fetch} from 'react-data/fetch';
-
-// Server
-
 import PostList from './PostList';
 
-function load(params) {
-  const allPosts = fetch('/posts?_expand=user').json();
-  return {
-    posts: <PostList posts={allPosts} />,
-  };
-}
-
-// Client
-
-function FeedPage(props, data) {
+export default function Feed() {
+  const posts = fetch('/posts?_expand=user').json();
   return (
     <>
       <h2>Feed</h2>
-      {data.posts}
+      <PostList posts={posts} />
     </>
   );
 }
-
-export default block(FeedPage, load);
diff --git a/fixtures/blocks/src/server/FeedPage.js b/fixtures/blocks/src/server/FeedPage.js
new file mode 100644
index 0000000000..2eb33bda76
--- /dev/null
+++ b/fixtures/blocks/src/server/FeedPage.js
@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {Suspense} from 'react';
+import PostGlimmer from './PostGlimmer';
+import Feed from './Feed';
+
+export default function FeedPage() {
+  return (
+    <Suspense fallback={<PostGlimmer />}>
+      <Feed />
+    </Suspense>
+  );
+}
diff --git a/fixtures/blocks/src/server/Link.block.js b/fixtures/blocks/src/server/Link.block.js
new file mode 100644
index 0000000000..da8f36bbbc
--- /dev/null
+++ b/fixtures/blocks/src/server/Link.block.js
@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {unstable_block as block} from 'react';
+
+// Client
+
+// TODO: delete this wrapper.
+
+import ClientLink from '../client/Link';
+
+function Link(props, _) {
+  return <ClientLink {...props} />;
+}
+
+export default block(Link);
diff --git a/fixtures/blocks/src/server/Post.block.js b/fixtures/blocks/src/server/Post.js
similarity index 56%
rename from fixtures/blocks/src/server/Post.block.js
rename to fixtures/blocks/src/server/Post.js
index 2d60cc874c..dc9fc10bc9 100644
--- a/fixtures/blocks/src/server/Post.block.js
+++ b/fixtures/blocks/src/server/Post.js
@@ -7,23 +7,14 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {unstable_block as block, Suspense} from 'react';
+import {Suspense} from 'react';
+import Comments from './Comments';
 
-// Server
+// TODO: Replace with asset reference.
+import loadLink from './Link.block';
 
-import loadComments from './Comments.block';
-
-function load(postId) {
-  return {
-    Comments: loadComments(postId),
-  };
-}
-
-// Client
-
-import Link from '../client/Link';
-
-function Post(props, data) {
+export default function Post({post}) {
+  const Link = loadLink();
   return (
     <div
       style={{
@@ -34,20 +25,16 @@ function Post(props, data) {
         maxWidth: 500,
       }}>
       <h4 style={{marginTop: 0}}>
-        {props.post.title}
+        {post.title}
         {' by '}
-        <Link to={`/profile/${props.post.user.id}`}>
-          {props.post.user.name}
-        </Link>
+        <Link to={`/profile/${post.user.id}`}>{post.user.name}</Link>
       </h4>
-      <p>{props.post.body}</p>
+      <p>{post.body}</p>
       <Suspense
         fallback={<h5>Loading comments...</h5>}
         unstable_avoidThisFallback={true}>
-        <data.Comments />
+        <Comments postId={post.id} />
       </Suspense>
     </div>
   );
 }
-
-export default block(Post, load);
diff --git a/fixtures/blocks/src/server/PostList.js b/fixtures/blocks/src/server/PostList.js
index 561771c9ce..0efe90cd86 100644
--- a/fixtures/blocks/src/server/PostList.js
+++ b/fixtures/blocks/src/server/PostList.js
@@ -9,16 +9,14 @@
 import * as React from 'react';
 import {Suspense, unstable_SuspenseList as SuspenseList} from 'react';
 import {preload} from 'react-data/fetch';
-
-import loadPost from './Post.block';
 import PostGlimmer from './PostGlimmer';
+import Post from './Post';
 
 export default function PostList({posts}) {
   return (
     <SuspenseList revealOrder="forwards" tail="collapsed">
       {posts.map(post => {
         preload(`/comments?postId=${post.id}&_expand=user`);
-        const Post = loadPost(post.id);
         return (
           <Suspense key={post.id} fallback={<PostGlimmer />}>
             <Post post={post} />
diff --git a/fixtures/blocks/src/server/ProfileBio.block.js b/fixtures/blocks/src/server/ProfileBio.js
similarity index 51%
rename from fixtures/blocks/src/server/ProfileBio.block.js
rename to fixtures/blocks/src/server/ProfileBio.js
index 52332ecf25..90797864d3 100644
--- a/fixtures/blocks/src/server/ProfileBio.block.js
+++ b/fixtures/blocks/src/server/ProfileBio.js
@@ -7,28 +7,15 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {unstable_block as block} from 'react';
-
-// Server
-
 import {fetch} from 'react-data/fetch';
 
-function load(user) {
-  return {
-    user,
-    bio: fetch(`/bios/${user.bioId}`).json(),
-  };
-}
-
-// Client
-
-function ProfileBio(props, data) {
+export default function ProfileBio({userId}) {
+  const user = fetch(`/users/${userId}`).json();
+  const bio = fetch(`/bios/${user.bioId}`).json().text;
   return (
     <>
-      <h3>{data.user.name}'s Bio</h3>
-      <p>{data.bio.text}</p>
+      <h3>{user.name}'s Bio</h3>
+      <p>{bio}</p>
     </>
   );
 }
-
-export default block(ProfileBio, load);
diff --git a/fixtures/blocks/src/server/ProfileNav.block.js b/fixtures/blocks/src/server/ProfileNav.block.js
new file mode 100644
index 0000000000..794a1d85fa
--- /dev/null
+++ b/fixtures/blocks/src/server/ProfileNav.block.js
@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {unstable_block as block} from 'react';
+
+// Client
+
+// TODO: delete this wrapper.
+
+import ClientProfileNav from '../client/ProfileNav';
+
+function ProfileNav(props, _) {
+  return <ClientProfileNav {...props} />;
+}
+
+export default block(ProfileNav);
diff --git a/fixtures/blocks/src/server/ProfilePage.block.js b/fixtures/blocks/src/server/ProfilePage.block.js
deleted file mode 100644
index 757cfd0389..0000000000
--- a/fixtures/blocks/src/server/ProfilePage.block.js
+++ /dev/null
@@ -1,61 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-/* eslint-disable import/first */
-
-import * as React from 'react';
-import {unstable_block as block, Suspense} from 'react';
-
-// Server
-
-import {fetch} from 'react-data/fetch';
-import loadProfileBio from './ProfileBio.block';
-import loadProfileTimeline from './ProfileTimeline.block';
-
-function load(userId, tab) {
-  const user = fetch(`/users/${userId}`).json();
-  let Tab;
-  switch (tab) {
-    case 'bio':
-      Tab = loadProfileBio(user);
-      break;
-    default:
-      Tab = loadProfileTimeline(userId);
-      break;
-  }
-  return {
-    Tab,
-    user,
-  };
-}
-
-// Client
-
-import {TabBar, TabLink} from '../client/TabNav';
-
-function ProfileTabNav({userId}) {
-  // TODO: Don't hardcode ID.
-  return (
-    <TabBar>
-      <TabLink to={`/profile/${userId}`}>Timeline</TabLink>
-      <TabLink to={`/profile/${userId}/bio`}>Bio</TabLink>
-    </TabBar>
-  );
-}
-
-function ProfilePage(props, data) {
-  return (
-    <>
-      <h2>{data.user.name}</h2>
-      <ProfileTabNav userId={data.user.id} />
-      <Suspense fallback={<h3>Loading...</h3>}>
-        <data.Tab />
-      </Suspense>
-    </>
-  );
-}
-
-export default block(ProfilePage, load);
diff --git a/fixtures/blocks/src/server/ProfilePage.js b/fixtures/blocks/src/server/ProfilePage.js
new file mode 100644
index 0000000000..8aaaa2e6a1
--- /dev/null
+++ b/fixtures/blocks/src/server/ProfilePage.js
@@ -0,0 +1,35 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import * as React from 'react';
+import {Suspense} from 'react';
+import {fetch} from 'react-data/fetch';
+import {matchRoute} from './ServerRouter';
+import ProfileTimeline from './ProfileTimeline';
+import ProfileBio from './ProfileBio';
+
+// TODO: Replace with asset reference.
+import loadProfileNav from './ProfileNav.block';
+
+// TODO: Router component?
+const ProfileRoutes = {
+  '/': props => <ProfileTimeline {...props} key="timeline" />,
+  '/bio': props => <ProfileBio {...props} key="bio" />,
+};
+
+export default function ProfilePage(props) {
+  const user = fetch(`/users/${props.userId}`).json();
+  const ProfileNav = loadProfileNav();
+  const match = matchRoute(props, ProfileRoutes);
+  return (
+    <>
+      <h2>{user.name}</h2>
+      <ProfileNav userId={user.id} />
+      <Suspense fallback={<h3>Loading...</h3>}>{match}</Suspense>
+    </>
+  );
+}
diff --git a/fixtures/blocks/src/server/ProfileTimeline.block.js b/fixtures/blocks/src/server/ProfileTimeline.block.js
deleted file mode 100644
index 1597d518b8..0000000000
--- a/fixtures/blocks/src/server/ProfileTimeline.block.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-/* eslint-disable import/first */
-
-import * as React from 'react';
-import {unstable_block as block} from 'react';
-
-// Server
-
-import {fetch} from 'react-data/fetch';
-import PostList from './PostList';
-
-function load(userId) {
-  const postsByUser = fetch(`/posts?userId=${userId}&_expand=user`).json();
-  return {
-    posts: <PostList posts={postsByUser} />,
-  };
-}
-
-// Client
-
-function ProfileTimeline(props, data) {
-  return <>{data.posts}</>;
-}
-
-export default block(ProfileTimeline, load);
diff --git a/fixtures/blocks/src/server/ProfileTimeline.js b/fixtures/blocks/src/server/ProfileTimeline.js
new file mode 100644
index 0000000000..96c0190f06
--- /dev/null
+++ b/fixtures/blocks/src/server/ProfileTimeline.js
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {fetch} from 'react-data/fetch';
+import PostList from './PostList';
+
+export default function ProfileTimeline({userId}) {
+  const posts = fetch(`/posts?userId=${userId}&_expand=user`).json();
+  return <PostList posts={posts} />;
+}
diff --git a/fixtures/blocks/src/server/ServerRouter.js b/fixtures/blocks/src/server/ServerRouter.js
new file mode 100644
index 0000000000..c15345e2aa
--- /dev/null
+++ b/fixtures/blocks/src/server/ServerRouter.js
@@ -0,0 +1,54 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+function tryMatch(props, def) {
+  const defSegments = def.split('/').filter(Boolean);
+  const routeSegments = props.route.split('/').filter(Boolean);
+  let innerProps = {...props};
+  while (routeSegments.length > 0) {
+    if (defSegments.length === 0) {
+      return null;
+    }
+    const urlSegment = routeSegments.shift();
+    const defSegment = defSegments.shift();
+    if (urlSegment === defSegment) {
+      continue;
+    }
+    if (defSegment[0] === ':') {
+      innerProps[defSegment.slice(1)] = urlSegment;
+      continue;
+    }
+    if (defSegment === '*') {
+      innerProps.route = '/' + urlSegment + routeSegments.join('/');
+      return innerProps;
+    }
+    return null;
+  }
+  if (defSegments.length === 0) {
+    return innerProps;
+  }
+  if (defSegments.length === 1 && defSegments[0] === '*') {
+    innerProps.route = '/';
+    return innerProps;
+  }
+  return null;
+}
+
+export function matchRoute(props, defs) {
+  for (let def in defs) {
+    if (!defs.hasOwnProperty(def)) {
+      continue;
+    }
+    const innerProps = tryMatch(props, def);
+    if (innerProps) {
+      const match = defs[def](innerProps);
+      return match;
+    }
+  }
+  throw Error('Not found.');
+}
diff --git a/fixtures/blocks/src/server/Shell.block.js b/fixtures/blocks/src/server/Shell.block.js
new file mode 100644
index 0000000000..053fd88468
--- /dev/null
+++ b/fixtures/blocks/src/server/Shell.block.js
@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+/* eslint-disable import/first */
+
+import * as React from 'react';
+import {unstable_block as block} from 'react';
+
+// Client
+
+// TODO: delete this wrapper.
+
+import ClientShell from '../client/Shell';
+
+function Shell(props, _) {
+  return <ClientShell {...props} />;
+}
+
+export default block(Shell);