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Your sandbox, just like any virtual machine, can expose ports. These ports let you connect to a process or app running in the sandbox.

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Reserved ports

The following ports are reserved by Blaxel’s system:
  • 443: This port hosts the main sandbox API and is exposed via HTTPS
  • 80: Reserved for system operations
  • 8080: Reserved for sandbox API functionality
You can expose and use any other port on your sandbox.

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Expose a port

You can expose specific non-reserved ports when creating a new sandbox by using the ports parameter. This allows you to access these ports from outside the sandbox, typically to create a preview URL on them. 
import { SandboxInstance } from "@blaxel/core";

// Create a new sandbox
const sandbox = await SandboxInstance.create({
  name: "my-sandbox",
  image: "blaxel/prod-base:latest",
  memory: 4096,
  ports: [{ target: 3000 }]
});

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Access the sandbox on a specific port

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Via the sandbox API

This option requires your request to be authenticated. You can access your sandbox on a specific port through the sandbox API using the following URL format: 
https://run.blaxel.ai/{workspace_id}/sandboxes/{sandbox_id}/port/{port_number}
For example to connect to port 3000 on my-sandbox: https://run.blaxel.ai/my-workspace/sandboxes/my-sandbox/port/3000

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Via a preview URL

Preview URLs provide a simple URL that maps to an internal port of your sandbox. You can either make this URL fully public or secure it with token-based authentication. Generally speaking:
  • for file and process management in your sandbox, use the sandbox API or SDK.
  • to access running applications within the sandbox (such as a NextJS preview server on port 3000), use a preview URL instead.

Create preview URLs

Expose applications running within the sandbox via a direct preview URL.
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