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Every sandbox can be reached by a public URL, which lets you expose and connect to services running inside it. This page covers how to get that URL, connect to a server inside the sandbox, and customize the Host header services receive. To control the sandbox’s outbound internet access, see Internet access. To require authentication on the public URL, see Restricting public access.

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Sandbox public URL

Every sandbox has a public URL that can be used to access running services inside the sandbox. 
import { Sandbox } from 'e2b'

const sandbox = await Sandbox.create()

// You need to always pass a port number to get the host
const host = sandbox.getHost(3000)
console.log(`https://${host}`)
The code above will print something like this: 
https://3000-i62mff4ahtrdfdkyn2esc.e2b.app
The first leftmost part of the host is the port number we passed to the method.

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Connecting to a server running inside the sandbox

You can start a server inside the sandbox and connect to it using the approach above. In this example we will start a simple HTTP server that listens on port 3000 and responds with the content of the directory where the server is started. 
import { Sandbox } from 'e2b'

const sandbox = await Sandbox.create()

// Start a simple HTTP server inside the sandbox.
const process = await sandbox.commands.run('python -m http.server 3000', { background: true })
const host = sandbox.getHost(3000)
const url = `https://${host}`
console.log('Server started at:', url)

// Fetch data from the server inside the sandbox.
const response = await fetch(url);
const data = await response.text();
console.log('Response from server inside sandbox:', data);

// Kill the server process inside the sandbox.
await process.kill()
This output will look like this: 
Server started at: https://3000-ip3nfrvajtqu5ktoxugc7.e2b.app
Response from server inside sandbox: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Directory listing for /</title>
</head>
<body>
<h1>Directory listing for /</h1>
<hr>
<ul>
<li><a href=".bash_logout">.bash_logout</a></li>
<li><a href=".bashrc">.bashrc</a></li>
<li><a href=".profile">.profile</a></li>
</ul>
<hr>
</body>
</html>

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Masking request host headers

You can customize the Host header that gets sent to services running inside the sandbox using the maskRequestHost / mask_request_host option. This is useful when your application expects a specific host format. 
import { Sandbox } from 'e2b'

// Create sandbox with custom host masking
const sandbox = await Sandbox.create({
  network: {
    maskRequestHost: 'localhost:${PORT}'
  }
})

// The ${PORT} variable will be replaced with the actual port number
// Requests to the sandbox will have Host header set to for example: localhost:8080
The ${PORT} variable in the mask will be automatically replaced with the actual port number of the requested service.