Bun React Ssr

Name: Bun React Ssr
Author: secondsky

secondsky/claude-skills

76 installs
202 repo stars
Updated August 4, 2026
secondsky/claude-skills

Helps with frontend development tasks during AI-assisted development.

About

bun react ssr is a Claude Code skill for frontend development. It helps solo builders move faster with AI-assisted coding.

bun react ssr
Frontend Development
AI-coding skill

Bun React Ssr by the numbers

76 all-time installs (skills.sh)
Ranked #1,129 of 2,245 Frontend Development skills by installs in the Skillselion catalog
Data as of Aug 5, 2026 (Skillselion catalog sync)

npx skills add https://github.com/secondsky/claude-skills --skill bun-react-ssr

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Installs	76
repo stars	★ 202
Last updated	August 4, 2026
Repository	secondsky/claude-skills ↗

What it does

Helps with frontend development tasks during AI-assisted development.

Files

SKILL.mdMarkdownGitHub ↗

Bun React SSR

Build custom server-rendered React applications with Bun.

Quick Start

# Initialize project
mkdir my-ssr-app && cd my-ssr-app
bun init

# Install dependencies
bun add react react-dom
bun add -D @types/react @types/react-dom

Basic SSR Setup

Server Entry

// src/server.tsx
import { renderToString } from "react-dom/server";
import App from "./App";

Bun.serve({
  port: 3000,
  async fetch(req) {
    const url = new URL(req.url);

    // Serve static files
    if (url.pathname.startsWith("/static/")) {
      const file = Bun.file(`./public${url.pathname}`);
      if (await file.exists()) {
        return new Response(file);
      }
    }

    // Render React app
    const html = renderToString(<App url={url.pathname} />);

    return new Response(
      `<!DOCTYPE html>
      <html>
        <head>
          <meta charset="utf-8">
          <meta name="viewport" content="width=device-width, initial-scale=1">
          <title>React SSR</title>
        </head>
        <body>
          <div id="root">${html}</div>
          <script src="/static/client.js"></script>
        </body>
      </html>`,
      {
        headers: { "Content-Type": "text/html" },
      }
    );
  },
});

console.log("Server running on http://localhost:3000");

Client Entry

// src/client.tsx
import { hydrateRoot } from "react-dom/client";
import App from "./App";

hydrateRoot(
  document.getElementById("root")!,
  <App url={window.location.pathname} />
);

React App

// src/App.tsx
interface AppProps {
  url: string;
}

export default function App({ url }: AppProps) {
  return (
    <div>
      <h1>React SSR with Bun</h1>
      <p>Current path: {url}</p>
      <button onClick={() => alert("Hydrated!")}>Click me</button>
    </div>
  );
}

Build Client Bundle

// build.ts
await Bun.build({
  entrypoints: ["./src/client.tsx"],
  outdir: "./public/static",
  target: "browser",
  minify: true,
  splitting: true,
});

# Build client
bun run build.ts

# Start server
bun run src/server.tsx

Streaming SSR

// src/server-streaming.tsx
import { renderToReadableStream } from "react-dom/server";
import App from "./App";

Bun.serve({
  port: 3000,
  async fetch(req) {
    const url = new URL(req.url);

    const stream = await renderToReadableStream(
      <App url={url.pathname} />,
      {
        bootstrapScripts: ["/static/client.js"],
        onError(error) {
          console.error(error);
        },
      }
    );

    // Wait for shell to be ready (Suspense boundaries)
    await stream.allReady;

    return new Response(stream, {
      headers: { "Content-Type": "text/html" },
    });
  },
});

With Suspense

// src/App.tsx
import { Suspense } from "react";

function SlowComponent() {
  // This would be a data fetching component
  return <div>Loaded!</div>;
}

export default function App({ url }: { url: string }) {
  return (
    <html>
      <head>
        <title>Streaming SSR</title>
      </head>
      <body>
        <div id="root">
          <h1>Fast Shell</h1>
          <Suspense fallback={<div>Loading...</div>}>
            <SlowComponent />
          </Suspense>
        </div>
      </body>
    </html>
  );
}

Data Fetching

Server-Side Data

// src/server.tsx
import { renderToString } from "react-dom/server";
import { Database } from "bun:sqlite";
import App from "./App";

const db = new Database("data.sqlite");

Bun.serve({
  async fetch(req) {
    const url = new URL(req.url);

    // Fetch data server-side
    const users = db.query("SELECT * FROM users").all();

    const html = renderToString(
      <App url={url.pathname} initialData={{ users }} />
    );

    return new Response(
      `<!DOCTYPE html>
      <html>
        <head><title>SSR</title></head>
        <body>
          <div id="root">${html}</div>
          <script>
            window.__INITIAL_DATA__ = ${JSON.stringify({ users })};
          </script>
          <script src="/static/client.js"></script>
        </body>
      </html>`,
      { headers: { "Content-Type": "text/html" } }
    );
  },
});

Client Hydration

// src/client.tsx
import { hydrateRoot } from "react-dom/client";
import App from "./App";

const initialData = (window as any).__INITIAL_DATA__;

hydrateRoot(
  document.getElementById("root")!,
  <App url={window.location.pathname} initialData={initialData} />
);

Routing

Simple Router

// src/Router.tsx
import { useState, useEffect } from "react";

interface Route {
  path: string;
  component: React.ComponentType;
}

interface RouterProps {
  routes: Route[];
  initialPath: string;
}

export function Router({ routes, initialPath }: RouterProps) {
  const [path, setPath] = useState(initialPath);

  useEffect(() => {
    const handlePopState = () => setPath(window.location.pathname);
    window.addEventListener("popstate", handlePopState);
    return () => window.removeEventListener("popstate", handlePopState);
  }, []);

  const route = routes.find((r) => r.path === path);
  const Component = route?.component || NotFound;

  return <Component />;
}

export function Link({ href, children }: { href: string; children: React.ReactNode }) {
  const handleClick = (e: React.MouseEvent) => {
    e.preventDefault();
    window.history.pushState({}, "", href);
    window.dispatchEvent(new PopStateEvent("popstate"));
  };

  return <a href={href} onClick={handleClick}>{children}</a>;
}

function NotFound() {
  return <h1>404 - Not Found</h1>;
}

CSS Handling

Inline Styles

const html = renderToString(<App />);

return new Response(
  `<!DOCTYPE html>
  <html>
    <head>
      <style>${await Bun.file("./src/styles.css").text()}</style>
    </head>
    <body>
      <div id="root">${html}</div>
    </body>
  </html>`,
  { headers: { "Content-Type": "text/html" } }
);

External Stylesheet

// Build CSS
await Bun.build({
  entrypoints: ["./src/styles.css"],
  outdir: "./public/static",
});

// Link in HTML
`<link rel="stylesheet" href="/static/styles.css">`

Development Setup

Hot Reload Development

// dev.ts
import { watch } from "fs";

const srcDir = "./src";
let serverProcess: Subprocess | null = null;

async function startServer() {
  serverProcess?.kill();
  serverProcess = Bun.spawn(["bun", "run", "src/server.tsx"], {
    stdout: "inherit",
    stderr: "inherit",
  });
}

// Watch for changes
watch(srcDir, { recursive: true }, async (event, filename) => {
  console.log(`Change detected: ${filename}`);
  await startServer();
});

await startServer();
console.log("Dev server watching...");

Production Build

// build-prod.ts

// Build client
await Bun.build({
  entrypoints: ["./src/client.tsx"],
  outdir: "./dist/public/static",
  target: "browser",
  minify: true,
  splitting: true,
  sourcemap: "external",
});

// Build server
await Bun.build({
  entrypoints: ["./src/server.tsx"],
  outdir: "./dist",
  target: "bun",
  minify: true,
});

console.log("Build complete!");

Common Errors

Error	Cause	Fix
`Hydration mismatch`	Server/client HTML differs	Check initial state
`document is not defined`	SSR accessing DOM	Guard with typeof window
`Cannot use hooks`	Hooks outside component	Check component structure
`Flash of unstyled content`	CSS not loaded	Inline critical CSS

Performance Tips

1. Use streaming SSR for faster TTFB 2. Inline critical CSS above the fold 3. Code split client bundle 4. Cache rendered HTML for static pages 5. Use Suspense for progressive loading