Dev Containers

CodeSandbox natively supports the Dev Containers specification (opens in a new tab), allowing you to customize your sandbox, install system-level dependencies, and run additional services.

Configuration

To configure your sandbox environment, create a .devcontainer/devcontainer.json file inside the root of the sandbox:

{
  "name": "Node.js",
  "image": "mcr.microsoft.com/devcontainers/javascript-node:18",
  "features": {
    "ghcr.io/devcontainers/features/python:1": {}
  }
}

In this example, we're installing Node v18 as base, with Python on top using Dev Container Features.

Alternatively, you can use a Dockerfile to build the Docker image when the sandbox boots:

{
  "name": "Node.js",
  "build": {
    "dockerfile": "./Dockerfile"
  }
}

Using Dev Containers in the SDK

When creating a sandbox, all shells will automatically run inside the Docker container specified in the Dev Container configuration.

const sandbox = await sdk.sandboxes.create({
  template: "node" // Template with Dev Container configuration
});
 
await sandbox.commands.run("node --version");

Since we use memory snapshots, the Docker container will already be running when you run your shell.

Docker Compose

You can run additional services using Docker Compose by adding a docker-compose.yml configuration to your Dev Container:

{
  "name": "Full Stack App",
  "dockerComposeFile": "docker-compose.yml",
  "service": "app",
  "workspaceFolder": "/workspace"
}

With a corresponding docker-compose.yml:

services:
  app:
    image: mcr.microsoft.com/devcontainers/javascript-node:18
    command: sleep infinity
 
  db:
    image: postgres:14
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: password