Quickstart

Start with custom sandbox templates

E2B templates allow you to define custom sandboxes. You can define the base image, environment variables, files to copy, commands to run, and a start command that runs during the template build and is captured in a snapshot — so the process is already running when you create a sandbox from that template. This gives you fully configured sandboxes with running processes ready to use with zero wait time for your users.

There are two ways how you can start creating a new template:

• using the CLI
• manually using the SDK

CLI

You can use the E2B CLI to create a new template.

1. Install the E2B CLI

   Install the latest version of the E2B CLI

2. Initialize a new template

   e2b template init
   
3. Follow the prompts

   Follow the prompts to create a new template.

4. Done

   Check the generated README.md file to see how to build and use your new template.

Manual

Install the packages

Requires the E2B SDK version at least 2.3.0

JavaScript & TypeScript

npm install e2b dotenv

Create the .env file

E2B_API_KEY=e2b_***

Create a new template file

Create a template file with the following name and content

JavaScript & TypeScript

// template.ts
import { Template, waitForTimeout } from 'e2b';

export const template = Template()
  .fromBaseImage()
  .setEnvs({
    HELLO: "Hello, World!",
  })
  .setStartCmd("echo $HELLO", waitForTimeout(5_000));

Create a development build script

JavaScript & TypeScript

// build.dev.ts
import 'dotenv/config';
import { Template, defaultBuildLogger } from 'e2b';
import { template } from './template';

async function main() {
  await Template.build(template, 'template-tag-dev', {
    cpuCount: 1,
    memoryMB: 1024,
    onBuildLogs: defaultBuildLogger(),
  });
}

main().catch(console.error);

Create a production build script

JavaScript & TypeScript

// build.prod.ts
import 'dotenv/config';
import { Template, defaultBuildLogger } from 'e2b';
import { template } from './template';

async function main() {
  await Template.build(template, 'template-tag', {
    cpuCount: 1,
    memoryMB: 1024,
    onBuildLogs: defaultBuildLogger(),
  });
}

main().catch(console.error);

Build the template

Build the development template

JavaScript & TypeScript

npx tsx build.dev.ts

Build the production template

JavaScript & TypeScript

npx tsx build.prod.ts

Create a new Sandbox from the Template

JavaScript & TypeScript

import 'dotenv/config';
import { Sandbox } from 'e2b';

// Create a Sandbox from development template
const sandbox = await Sandbox.create("template-tag-dev");

// Create a Sandbox from production template
const sandbox = await Sandbox.create("template-tag");

The template name is the identifier that can be used to create a new Sandbox.

Creating many templates

There is no practical limit on how many templates you can have. It’s perfectly fine to create tens or hundreds of thousands of templates — for example, one template per customer, per project, or per agent run.

The template build environment is a full sandbox environment, so you can do anything during the build that you can do inside a running sandbox, including running Docker containers as part of the setup.

Compared to snapshots, templates start faster and use fewer resources because the guest OS is restarted before the long-running process is captured and prefetching is significantly more effective. If your workload involves spinning up many per-customer or per-project environments, prefer templates over snapshots.

Layering templates with fromTemplate

When you build many similar templates (e.g. a customer-specific template per customer that all share the same base setup), use fromTemplate to start from an existing template instead of rebuilding the shared layers from scratch each time. This keeps per-customer builds fast and reuses the cached base.

JavaScript & TypeScript

import { Template } from 'e2b'

// Per-customer template built on top of a shared base template
export const template = Template()
  .fromTemplate('my-base-template')
  .copyDirectory('./customers/acme', '/app/config')
  .setEnvs({ CUSTOMER_ID: 'acme' })

Build limits

Template builds are subject to the following limits:

• Max build duration: Builds can run for up to 1 hour. If a build exceeds this, it will be terminated.
• Max vCPUs per build: 8 on Hobby, 8+ on Pro, custom on Enterprise.
• Max memory per build: 8 GB on Hobby, 8+ GB on Pro, custom on Enterprise.
• Max disk size per build: 10 GB on Hobby, 20+ GB on Pro, custom on Enterprise.
• Concurrent builds: 20 on Hobby and Pro, custom on Enterprise.

See Billing & limits for the full list of plan limits. Need higher limits? Contact [e-mail].