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Container web server

Learn about how to run a web server inside your Actor, which enables you to communicate with the outer world via both UI and API.

Each Actor run is assigned a unique hard-to-guess URL (e.g., which enables HTTP access to an optional web server running inside the Actor run's Docker container. The URL is available in the following places:

  • In the web application, on the Actor run details page as the Container URL field.
  • In the API as the containerUrl property of the Run object.
  • In the Actor run's container as the ACTOR_WEB_SERVER_URL environment variable.

The web server running inside the container must listen at the port defined by the ACTOR_WEB_SERVER_PORT environment variable (typically 4321). If you want to use another port, simply define the ACTOR_WEB_SERVER_PORT environment variable with the desired port number in your Actor version configuration - see Custom environment variables for details.

The following example demonstrates how to start a simple web server in your Actor:

// npm install express
import { Actor } from 'apify';
import express from 'express';

await Actor.init();

const app = express();
const port = process.env.ACTOR_WEB_SERVER_PORT;

app.get('/', (req, res) => {
res.send('Hello world from Express app!');

app.listen(port, () => console.log(`Web server is listening
and can be accessed at

// Let the Actor run for an hour
await new Promise((r) => setTimeout(r, 60 * 60 * 1000));

await Actor.exit();