Modern Alternative Runtimes: Deno and Bun.

In Simple Words:

• Bun: Built in Zig with JavaScriptCore engine. Blazingly fast startup, built-in package manager, bundled test runner, and native TypeScript support.
• Deno: Built in Rust with V8. Emphasizes secure-by-default sandbox permissions, Web standard APIs, built-in tooling, and native TypeScript compilation.

// Native TypeScript and built-in HTTP server in Bun:
Bun.serve({
  port: 3000,
  fetch(req) {
    return new Response("Hello from Bun's ultra-fast runtime!");
  },
});