bun.sh/docs/ecosystem/express.md

Projects that use Express and other major Node.js HTTP libraries should work out of the box.

{% callout %} If you run into bugs, please file an issue in Bun's repo, not the library. It is Bun's responsibility to address Node.js compatibility issues. {% /callout %}

import express from "express";

const app = express();
const port = 8080;

app.get("/", (req, res) => {
  res.send("Hello World!");
});

app.listen(port, () => {
  console.log(`Listening on port ${port}...`);
});

Bun implements the node:http and node:https modules that these libraries rely on. These modules can also be used directly, though Bun.serve is recommended for most use cases.

{% callout %} Note — Refer to the Runtime > Node.js APIs page for more detailed compatibility information. {% /callout %}

import * as http from "node:http";

http
  .createServer(function (req, res) {
    res.write("Hello World!");
    res.end();
  })
  .listen(8080);